The Behavior of Two Different Particles Linked by Quantum Entanglement
Science Photo Library / Alamy
We have a groundbreaking method to measure quantum entanglement in solids, paving the way for significant advancements in quantum technology and fundamental physics.
Researchers face limitations in quantifying quantum entanglement—the phenomenon that correlates the behavior of distant quantum particles. The Bell test is one technique that assesses whether two particles are entangled or facilitates the intentional creation of entanglements in quantum computing setups.
However, detecting entangled particles within a material is far more complex. This capability is critical in developing advanced quantum computing and communication devices that rely on entanglement.
Allen Scheie from Los Alamos National Laboratory, along with his team, has dedicated over 50 years to refining this technology, and they have now confirmed its effectiveness.
“We have verified that it works flawlessly, and we’re taking steps to extend its application across various materials,” Scheie stated.
The innovative technique involves bombarding a sample material with neutrons and capturing them with a detector. Since the 1950s, studying the properties of these neutrons has allowed researchers to unveil the arrangement and behavior of quantum particles within substances. Scheie and his colleagues utilized this approach to calculate quantum Fisher information (QFI), a metric that indicates the minimum number of entangled quantum particles necessary to influence a neutron in a detected manner.
The research team applied their method to various magnetic materials, including well-documented crystals of potassium, copper, and fluorine. Team member Pontus Laurel emphasized that their findings closely aligned with computer simulations of the quantum architectures of these crystals, affirming the reliability of their new approach. “The experimental and theoretical predictions matched surprisingly well,” he stated.
Laurel added that while previous studies explored QFI and similar metrics as potential “witnesses to entanglement,” their group has established a clear, dependable, and broadly applicable measurement technique. Much of their effort focused on perfecting the nuances, enabling experiments with diverse materials, including those suitable for future device development.
Notably, their method remains effective irrespective of whether a robust mathematical model exists for the material, even when the samples are incomplete. “That’s the remarkable aspect: you can measure quantum Fisher information under any circumstances,” Scheie remarked. The research was presented at the American Physical Society Global Physics Summit on March 17th in Denver.
Within the next month, the researchers aim to enhance their methodology by measuring QFI (quantum equivalent at the transition point from water to ice) in materials approaching a phase transition. At this juncture, theoretical models often falter or predict skyrocketing entanglement, creating a prime opportunity for groundbreaking quantum discoveries, according to Scheie.
Quantum computers capable of breaking internet security codes are rapidly approaching reality. Discoveries from two research teams highlight the strides being made, indicating that current quantum machines are already over halfway to the necessary scale.
Both studies focus on cryptographic methods centered around the Elliptic Curve Discrete Logarithm Problem (ECDLP)—a mathematical challenge ideally suited for data encryption. ECDLP has been widely adopted for securing internet communications, including banking transactions and major cryptocurrencies like Bitcoin.
While classical computers struggle to breach elliptical curve-based codes, it has been understood since the 1990s that quantum computers possess the ability to do so. However, building a sufficiently powerful quantum computer seemed a far-off challenge due to engineering limits.
Recent advancements in both theory and engineering have drastically accelerated this timeline. Theoretical research has led to optimized quantum hacking algorithms, significantly lowering the required quantum computing power. For instance, in 2019, estimates indicated a need for 20 million qubits to crack a related encryption system called RSA-2048; by February, that figure plummeted to just 100,000 qubits.
Furthermore, while the most sophisticated quantum computers in 2019 barely exceeded 50 qubits, today’s leading machines have surpassed 1,000 qubits, with the largest unused qubit array containing 6,100 qubits.
Currently, Dorev Bruchstein and his team suggest that ECDLP could require machines with only 10,000 qubits. Though this decoding would still take years, Ryan Babush and his colleagues from Google’s Quantum Research division have shown that just 500,000 qubits could perform the task in as little as nine minutes.
“Today marks a significant moment for quantum computing and cryptography,” says Justin Drake of the Ethereum Foundation, which collaborates with researchers at Google. He shared this insight via social media.
Bruchstein’s estimates are based on qubits formed from ultracold atoms manipulated by lasers, providing increased connectivity that likely reduces the number of required qubits.
Bruchstein envisions a potential array of 10,000 ultracold qubits being realized within a year, yet controlling and operating them with precision will be a significant challenge. Proper interaction between qubits is critical, eliminating the possibility of merely linking multiple existing machines together.
Bruchstein anticipates that a fully operational quantum computer may not be available until the decade’s end. “We’re making substantial progress, but it’s beginning to feel feasible to build,” he explains.
Concerns Over Cryptocurrency Security
The Google team derived their conclusions based on a different type of quantum computer using superconducting circuits. These quantum systems are often viewed as more advanced, and Google prioritizes their development.
The researchers have refrained from commenting publicly about the study. However, the paper indicates that “resource estimations could be dramatically lowered with more aggressive hardware capabilities,” implying that the 500,000 qubit target might be conservative. Notably, they refrain from providing details about the decryption algorithm for security reasons.
They also indicate that such quantum computers could potentially intercept cryptocurrency transactions and reroute funds for a brief period before recording, effectively enabling theft.
Given the findings from both studies, it’s clear that Bitcoin may be more susceptible to quantum attacks sooner than previously understood, according to Scott Aaronson from the University of Texas at Austin.
Stefano Gozioso from the University of Oxford notes that both configurations of quantum computers encounter substantial engineering hurdles before practical application is achievable, particularly the ultracold atom method, which is still largely experimental. He emphasizes the growing urgency for security in the digital realm.
Some internet browsers already implement encryption impervious to quantum attacks, termed post-quantum cryptography (PQC). While traditional banking systems may adapt post-attack, a decentralized cryptocurrency framework might be far more vulnerable, according to Gozioso. Google suggests that organizations transition to PQC by 2029 as the need intensifies.
“This is precisely why we initiated the PQC standardization project over a decade ago,” states Dustin Moody from the National Institute of Standards and Technology (NIST). “We anticipated that advancements in quantum hardware would coincide with algorithmic progress.”
NIST has identified several PQC algorithms with the potential to become future security standards as practical quantum computers emerge, with the U.S. federal government targeting a transition by 2035. However, Moody warns that organizations should act promptly. “These studies reinforce that the window for migration is limited, making immediate action imperative,” he concludes.
Credit: University of Illinois at Urbana-Champaign/L. Brian Stauffer
During my first year of graduate studies, I shared an office with an older graduate student who was quietly conducting pivotal research. Upon conversing with him, I discovered he was “working with Tony on the theory of glasses.” It soon became evident to me that the physics behind glasses posed significant complexities and that I should have recognized Tony’s name sooner. My initial meeting with Anthony James Leggett was enlightening—a courteous British gentleman in his 70s, with the wisdom of a seasoned educator and an undeniable sparkle in his eye. He was a Nobel laureate, knighted by the British Empire, recipient of numerous accolades, and a pioneer in quantum theory, notably examining the enigmas of cold quantum realms. He passed away on March 8, leaving behind a legacy fueled by his integrity, curiosity, and numerous aspiring scientists, yet to many, he simply remained Tony.
Born in 1938 in South London, Leggett attended a Jesuit school where his father instructed in physics and chemistry. Originally earning a degree in classical literature, philosophy, and ancient history from Oxford University, he ultimately succumbed to the allure of physics, pursuing it further at the University of Illinois at Urbana-Champaign (UIUC) for his doctorate.
At that time, UIUC served as a hub for physicists delving into novel quantum materials. Many of these materials exhibited extraordinary characteristics only at ultra-low temperatures. Leveraging his prior expertise in cryogenics, Tony redirected his focus towards the peculiarities of helium-3. He recounted a memorable encounter with physicists John Bardeen and Leo Kadanoff, who introduced him to their groundbreaking experiments with ultracold helium. Although he attempted to encapsulate these discoveries mathematically, initial distractions led him to maintain an intricate relationship with helium-3 over the next decade.
In a serendipitous twist during a rain-soaked 1972 vacation, he met experimentalist Robert Richardson, whose discussion of helium-3 experiments significantly impacted Leggett’s research career. Following their conversation, Leggett aimed to develop a formal proof demonstrating the impossibility of observed phenomena aligning with established quantum mechanics. This moment hinted at potential discrepancies within the framework of quantum physics itself.
Leggett’s subsequent investigations revealed that while quantum principles held, helium-3 exhibited unprecedented traits rarely seen in other cryogenic systems. As researchers explored the unusual behavior of materials under extreme cold, they uncovered effects like superconductivity, where electrons cohesively pair in a unique quantum state—enabling perfect electrical conductivity. Intrigued by whether helium-3 could exhibit comparable superfluid qualities, Leggett meticulously delved into its properties.
Ultimately, Leggett crafted a comprehensive theory around ultracold helium-3, establishing that its atoms can form multiple types of superfluids and introducing a novel form of symmetry breaking, elucidating previously obscure experimental results.
Richardson had won the Nobel Prize for his 1966 helium-3 research, while Leggett received his Nobel Prize for groundbreaking theoretical contributions in 2003.
Anthony Leggett: Nobel Prize in Physics 2003
Credit: Jonas Ekströmmer/AFP via Getty Images
Reflecting on the announcement of his Nobel Prize in 2003, Leggett expressed the elation felt by many during that early morning news. His former graduate advisor, Smitha Vishveshwara, attested to his profound kindness and wisdom, which inspired countless individuals at UIUC. Tony joined the university in 1983, and I had the privilege of working with him as a postdoctoral fellow starting in 2002. He was often deep in thought, too busy at his roundtable in the Institute for Condensed Matter Physics, now bearing his name, to engage with anyone.
Beyond his groundbreaking work on superfluid helium-3, Leggett was passionate about broader questions that questioned the foundations of quantum physics. He delved into intriguing theories regarding whether the quantum realm might apply to large-scale objects—a notion he explored in an interview post-Nobel Prize celebration. Leggett noted, “If we genuinely adhere to quantum theories, I believe the perceptions we hold about the physical world will differ significantly by AD 3000.” He intriguingly speculated about a potential evolution in physical understanding, pondering new paradigms that may emerge.
Exploring Quantum Physics Frontiers
To probe the fascinating boundaries of quantum mechanics, Leggett, alongside Anupam Garg, developed a mathematical test in 1985 for assessing the quantum characteristics of large objects. This experiment, now known as the Leggett-Garg inequality, evaluates object behavior over time—offering insights into whether quantum laws govern these entities. Researchers worldwide have since executed the Leggett-Garg experiment on various systems, including photons and minuscule crystals—sparking advancements in quantum physics.
His inquiries regarding the intersection of macroscopic occurrences and quantum phenomena laid the groundwork for another Nobel Prize-winning experiment last year. John Martinis, from the quantum computing company QoLab, highlighted that collaboration on a large-scale circuit experiment stemmed from ideas Leggett initially discussed in the early ’80s. The work confirmed the manifestation of quantum effects in systems of superconducting circuits, echoing Leggett’s extensive knowledge that inspired Martinis and his team as they approached lab construction.
Underlining Leggett’s keen observational talents, David Waxman, a former student, noted, “Tony had an exceptional ability to perceive what others might overlook—he saw potential where many dismissed a mere fluctuation on a graph as trivial.”
Leggett consistently advised young physicists to advocate for their inquiries. He remarked, “If conventional wisdom mystifies you, take time to unravel it, and don’t succumb to peer pressure asserting that it is well understood.” He emphasized that “research conducted with integrity is never fruitless,” allowing for new perspectives to emerge from long-abandoned ideas.
Although I departed UIUC in spring 2020, I can still envision him—an intellectual giant—engaged in profound contemplation at his desk. I firmly believe he never ceased his quest for knowledge, perpetually inclined to uncover nature’s hidden secrets. I wish I had explored the unexplored research awaiting revelation within his desk drawers.
Key Components of a New Rubidium Atom Cooling Setup
Tomasz Kawalec CC BY-SA 4.0
A groundbreaking quantum device utilizing giant rubidium atoms may redefine temperature measurement.
While some nations utilize Celsius or Fahrenheit to measure temperature, physicists universally rely on Kelvin. This unit signifies “absolute temperature,” where 0 Kelvin represents the lowest temperature permitted by physical laws. However, confirming the accuracy of a 1 Kelvin measurement is a meticulous endeavor.
“When making absolute temperature measurements, one typically purchases a temperature sensor calibrated against another sensor, and the chain continues. Ultimately, one of those sensors was previously sent to the American Standards Institute,” explains Noah Schlossberger from NIST in Colorado.
Schlossberger and his team have developed an innovative device leveraging quantum mechanics to directly measure Kelvin, eliminating the need for extensive sensor calibrations.
This device, a compact metal and glass structure housing trapped rubidium atoms, employs lasers to displace outer electrons far from the atomic nucleus, resulting in significantly enlarged atoms. Subsequently, the researchers cool these atoms to roughly 0.5 milliKelvin—about 600,000 times cooler than room temperature—using lasers and electromagnetic fields.
Consequently, the outer electrons of rubidium atoms exhibit heightened sensitivity to minute temperature fluctuations. When exposed to certain quantum states, these electrons “jump,” allowing the device to function effectively as a temperature sensor. Established mathematical models can accurately relate the temperature difference necessary for such jumps, facilitating a new Kelvin definition.
The International Bureau of Weights and Measures similarly defines Kelvin via various quantum constants. Yet, institutions like NIST often resort to non-quantum devices for calibration. The new quantum device aims to deliver a calibration-free definition of Kelvin.
According to Schlossberger, “Every rubidium atom behaves identically in the same conditions. You can replicate a device anywhere in the world, and it will perform the same way.” This uniformity is crucial for maintaining high-precision instruments, such as atomic clocks, which require operation at very low Kelvin temperatures.
However, the prototype still faces challenges: it struggles with accurately detecting quantum states and is currently too cumbersome for practical use. Researchers are actively refining the design for enhanced practicality and precision.
A groundbreaking team of scientists at New York University has successfully developed a unique version of an exotic phase of matter where particles are acoustically suspended and interact through sound wave exchanges.
Morel et al. observed a revolutionary type of time crystal with particles suspended on a cushion of sound while interacting through sound waves. Image credit: David Song / New York University.
Time crystals—collections of particles that “keep time”—are poised to transform fields like quantum computing and data storage.
The particles present in this innovative time crystal defy Newton’s third law of motion, which posits that every action has an equal and opposite reaction, emphasizing a balance in forces.
Unlike traditional particles, these new particles interact independently, are not strictly bound by equilibrium forces, and exhibit non-reciprocal movement.
Remarkably, these time crystals are visible to the naked eye and are housed in a compact, one-foot-tall device that can easily be held in hand.
“The speaker emits sound waves, allowing us to place small particles at the pressure nodes, effectively suspending them against gravity,” stated Leela Elliott, an undergraduate at New York University.
The time crystal is constructed using Styrofoam beads that are suspended by these sound waves, initially employed as an acoustic levitation device to maintain the beads in the air.
“We discovered that a simple system of two particles suspended within an acoustic standing wave can spontaneously oscillate and generate time crystal effects due to their unbalanced interactions,” explained Mia Morell, a graduate student at NYU.
“When these airborne particles interact, they do so by exchanging scattered sound waves.”
“Specifically, larger particles scatter more sound than smaller ones,” she added.
“Consequently, the influence of large particles on small particles is greater than the reverse.”
“This results in an asymmetry in interactions between small and large particles.”
“Imagine two ferries of different sizes approaching a pier,” she said.
“Each ferry creates waves that displace the other, but the impact varies based on size.”
This discovery broadens the scope of potential applications for these crystals, promising advancements in technology and industry.
“Time crystals exhibit a high degree of autonomy, making independent decisions and persisting on their path,” stated Professor David Greer of New York University.
“They are intriguing not only for their potential applications but also due to their visually exotic and complex structure.”
“In contrast, our system stands out because it’s surprisingly straightforward.”
The team’s key findings were published in the Physical Review Letters.
_____
Mia C. Morell et al. 2026. Non-reciprocal wave-mediated interactions power the classical time crystal. Physics Review Letters, 136, 057201; doi: 10.1103/zjzk-t81n
Two Engineers Working on Kilimanjaro’s Quantum Computers
Credit: Qilimanjaro
Quantum computers, once viewed as futuristic devices, are now becoming more accessible. With DIY kits, individuals with sufficient resources and engineering expertise can assemble their own quantum systems.
The Barcelona-based quantum computing firm, Kilimanjaro, is revolutionizing access to this technology through their EduQit initiative. Inspired by the concept of “flat-pack furniture,” Kilimanjaro supplies all necessary components, allowing users to assemble their own quantum computing kits.
Each EduQit kit features a chip crafted from tiny superconducting circuits, which is essential for quantum computation. It includes a specialized refrigerator to install the chip, alongside electronics that utilize radio and microwave signals to govern the chip and interpret its calculations—all bundled with racks, power cables, and supplementary devices to construct the entire quantum computer.
While assembling the kit may seem challenging, comprehensive instructions are provided. As Marta Estarellas from Kilimanjaro states, their team offers training and support throughout the construction process. Training may take up to three months, with the complete system ready for operation in approximately ten months.
The EduQit quantum computer boasts five qubits and occupies less than one-tenth the space of cutting-edge models, yet is available for the relatively modest price of about 1 million euros. In contrast, most existing quantum computers are produced by major tech corporations or well-funded startups and research facilities. To illustrate, Google aims to reduce component expenses by a factor of ten, as current systems can cost less than $1 billion. See more about quantum computing costs in a recent study.
Kilimanjaro Quantum Chip
Credit: Qilimanjaro
While compact commercial machines are available, they usually don’t include complete kits. For instance, Rigetti, a California company, offers small superconducting quantum computers for research starting at around $900,000, which only encompass the main chip and a few components—akin to obtaining just a motherboard without peripherals.
Kilimanjaro aspires to furnish comprehensive kits to numerous research institutions, where access to quantum computing technology remains limited due to funding constraints. Their goal is to equip the next generation of researchers with hands-on experience in building and operating quantum systems.
Currently, students engage with quantum computers via cloud platforms or simulated models. However, EduQit aims to provide practical skills in quantum computing, potentially becoming the educational equivalent of the Raspberry Pi—small, easily customizable computers that evolved from learning tools into essential resources for hobbyists and scientists alike.
Quantum computing holds promise for performing complex calculations unattainable even by today’s top supercomputers. From breaking secure internet codes to simulating molecular behavior for drug discovery, the potential is vast. Yet, the fragility and susceptibility to errors of quantum chips pose significant challenges in realizing this technology’s full potential.
A quantum computer like EduQit would have competed with the most advanced lab systems a decade ago. Its availability as a DIY kit showcases the rapid advancements in quantum computing technology in recent years.
As Katia Moskovich notes, companies like Quantum Machines highlight the multitude of unanswered questions regarding the future of quantum computing, emphasizing that broader experimentation will enhance understanding and innovation in this field.
Quantum computing is advancing, but error correction remains a significant challenge. The current limitations of this technology are its inability to operate effectively due to persistent errors, which researchers are actively working to address.
In traditional computers, errors are managed using established redundancy techniques, leveraging extra bits to recognize when data is inaccurately switched. However, in the realm of quantum computing, the principles of quantum mechanics complicate this process, as information cannot be duplicated. Instead, error correction must utilize the unique attributes of qubits, including quantum entanglement.
Logical qubits, essential for processing in quantum systems, distribute information across multiple qubits to mitigate errors. Innovative approaches to creating and managing these logical qubits are vital for overcoming existing limitations.
Experts like Robert Schoelkopf from Yale University highlight the exciting developments in this field, indicating that both theory and application are finally converging.
However, one major challenge is the substantial number of qubits required to construct a reliable logical qubit, which raises the cost and complexity of quantum machines. Research by Summer Rain Forest Peng at the International Quantum Academy in China reveals that this requirement can be minimized.
Through innovative techniques, researchers have demonstrated that merging merely two superconducting qubits with a small resonator can yield a larger qubit with a reduced error rate and enhanced error detection capabilities. Additionally, utilizing quantum entanglement allows for increased computational efficiency without introducing additional errors.
Further advancements have been made by Schorkopf’s team, showcasing operations implemented with low-error qubits occurring only once in a million operations, significantly improving reliability in tasks essential to quantum programming.
In the quest for a functional quantum computer, it’s clear that achieving thousands of logical qubits is necessary, and some errors will inevitably occur. Companies like Quantum Elements, led by Ariane Vezvai, investigate ways to bolster error protection methods, drawing parallels to using an umbrella in the rain.
Strategically, keeping qubits active is crucial in preserving their unique quantum properties. Recent findings indicate that administering an additional ‘kick’ of electromagnetic radiation to idle qubits can enhance their entanglement reliability.
The precise methodology for engineering physical qubits into effective logical qubits is imperative, especially for high-stakes calculations, as delineated by David Muñoz Ramo from Quantinuum, who identifies a pivotal experiment involving hydrogen’s lowest energy state.
Such advancements in quantum error correction are absolutely critical for the viability of future quantum computing solutions. James Wootton at Moth Quantum emphasizes that while quantum computers are not yet free from errors, the foundational engineering is beginning to take shape.
Quantum computers may revolutionize chemical property calculations
Credit: ETH Zurich
Recent analyses suggest quantum chemical calculations, which could enhance drug development and agricultural innovation, may not be the game-changer for quantum computers that many hoped.
As advancements in quantum computer technology progress rapidly, the most compelling applications for continued investment remain uncertain. One widely considered option is solving complex quantum chemistry problems, including energy level calculations for molecules critical to biomedicine and industry. This requires managing the behavior of numerous quantum particles (electrons in a molecule) simultaneously, aligning well with quantum computing’s strengths.
However, Xavier Weintal and his team at CEA Grenoble in France have demonstrated that the leading quantum algorithms for this purpose may be of limited utility.
“In my view, it’s likely doomed; it’s not definitively doomed, but it’s probably facing insurmountable challenges,” remarks Weintal on the feasibility of using quantum computers for molecular energy calculations.
The team categorized their analysis into two segments: one focused on current noisy quantum computers, and another on future fault-tolerant quantum systems.
Using error-prone quantum computers, energy levels can be computed via variational quantum eigensolver (VQE) algorithms, yet the outcome’s accuracy is heavily influenced by noise levels.
According to their findings, for VQE to match the accuracy of chemical algorithms running on classical systems, noise levels in quantum computers would need significant reduction, essentially qualifying them as fault-tolerant. Notably, no practical fault-tolerant quantum computer yet exists.
Several firms are racing to develop fault-tolerant quantum systems within the next five years. These advanced devices aim to utilize quantum phase estimation (QPE) for calculating molecular energy levels. While the error issue may be largely addressed here, the study uncovers a daunting challenge dubbed the “orthogonality catastrophe.”
Simply stated, as molecular size increases, the likelihood of QPE accurately determining the lowest energy level diminishes exponentially. Consequently, Thibault Louve, from French quantum computing enterprise Quobly, states that even with superior quantum computers, instances where QPE is practically viable are extremely limited. He argues that the ability to execute this algorithm should be viewed as a benchmark for quantum computer maturity rather than a primary tool for chemists.
“There’s a tendency to overstate quantum computers’ potential in this area; many assume the arrival of quantum capabilities will render classical methods for quantum chemistry obsolete,” asserts George Booth, a professor at King’s College London, who wasn’t involved in this research. “This study calls attention to considerable challenges in achieving accurate molecular simulations that will persist even in the fault-tolerant era, raising doubts about the immediate success of quantum chemistry within quantum computing.”
Nevertheless, quantum computers hold promise for various chemistry applications. For instance, they can simulate the alterations in a chemical system when subjected to disruptions, such as exposure to laser beams.
Discover the QuEra Quantum Computer Based on Cryogenic Atoms
Credit: Cuella
An innovative algorithm called phantom code has the potential to enable quantum computers to execute complex programs error-free, addressing a critical barrier to the broader adoption of quantum technology.
Initially, many physicists were skeptical about the viability of quantum computers due to their susceptibility to errors that are challenging to rectify. Various types of quantum computers are already operational and have shown promise in facilitating scientific research and exploration. Nevertheless, the industry is still grappling with the challenge of minimizing computational mistakes.
Traditional error correction techniques permit quantum computers to store information accurately, but their computational demands can be substantial. According to Shayan Majidi of Harvard University, this creates inefficiencies.
To tackle this issue, Majidi and his research team concentrated on complex calculations that require numerous steps, often resulting in prolonged execution times and heightened error risks.
Quantum computers utilize basic units known as qubits. These computations frequently involve logical qubits: clusters of qubits cooperating to lower error rates. In order to avoid computational inaccuracies, devices manipulate these logical qubits. For instance, physical qubits are usually subjected to lasers or microwaves to connect multiple logical qubits or alter their quantum states.
The phantom code innovation allows the entanglement of multiple logical qubits without necessitating any physical manipulations, hence its moniker “phantom.” This efficiency translates to fewer actions required for calculations, thereby diminishing the likelihood of errors.
In their experiments, Majidi and his colleagues ran computer simulations to evaluate the phantom code on two distinct tasks: preparing specialized qubit states that are essential for computations, and simulating simplified models of quantum materials. Their findings indicated that this method yielded results that were up to 100 times more accurate than conventional error correction methods by minimizing the need for physical operations.
While phantom codes may not be applicable to every quantum computing task, according to Majidi, they are particularly useful in scenarios that demand extensive entanglement. This method doesn’t generate new entanglements; instead, it optimally utilizes existing ones. As Majidi puts it, “It’s not a free lunch; it’s just a lunch that was already there, and we weren’t consuming it.”
Mark Howard, researchers at the University of Galway in Ireland, liken the selection of error-correcting codes for quantum computing to choosing protective armor. While plate armor may provide superior protection at the expense of weight and versatility, phantom code offers flexibility but requires more qubits compared to traditional strategies, making it a partial solution to quantum error challenges.
Dominic Williamson and his team at the University of Sydney in Australia point out that the competitive viability of phantom codes versus other error correction methods remains uncertain and may hinge on future advancements in quantum hardware.
Majidi’s team is collaborating closely with colleagues developing quantum computers based on extremely cold atoms. He envisions that insights gained from phantom code, along with an understanding of qubit capabilities, will pave the way for new strategies tailored specifically to both tasks and hardware implementations in quantum computing.
Mehdi Namazi aims to revolutionize communication through quantum entanglement.
Along with his team at Qunnect, he has dedicated nearly a decade to developing a device that enables the sharing of quantum-entangled light particles (photons), making secure communication a reality.
Located at Qunnect’s headquarters in Brooklyn, New York, a state-of-the-art table is filled with lasers, lenses, special crystals, and other components essential for manipulating light. All of this technology will be elegantly packaged in striking magenta boxes and dispatched to those advancing future communication technology.
Against the backdrop of the iconic New York skyline, Namazi unveils an electronic device that may seem unremarkable at first. However, when stacked, these boxes form what the company refers to as the Carina rack, capable of performing extraordinary quantum functions.
In February, the Qunnect team used these racks for “entanglement swapping” over a 17.6-kilometre fiber-optic connection between Brooklyn and Manhattan through commercial data centers.
Entanglement exchange involves transferring entangled properties from one photon pair to another. Once photons are entangled, they demonstrate extreme sensitivity to tampering, making it exceedingly difficult to steal information without detection. This swapping technique extends the essence of unhackable communication to long-distance quantum internet applications.
Qunnect successfully exchanged quantum entanglements among 5,400 photon pairs every hour while the network operated autonomously for several days. Previously established experiments recorded significantly lower rates of entanglement exchange.
Before the Carina Rack can perform its magic, entangled photons must be generated using another device. At the heart of this “entanglement source” lies a glass and metal box containing rubidium atoms vapor, illuminated by laser light to produce photon pairs. Namazi recounts how precise adjustments to the laser beam’s angle increased the number of entangled photons produced.
Once generated, the Carina Rack transmits these photons through a fiber network to laboratories across New York City, including prestigious institutions like New York University and Columbia University.
Namazi illustrates how one might set up a personal entanglement sharing system to send super-secure messages. “With two Carina racks, we can distribute entanglements within hours,” he states.
Qunnect maintains one such rack in a Manhattan-based commercial data center managed by QTD Systems. When asked, QTD’s Peter Feldman echoed Namazi’s assurance: “You don’t need to know anything about quantum physics.” The systems that sustain photon entanglement in Qunnect’s network can be operated remotely, allowing autonomous function for weeks.
Qunnect’s Advanced Quantum Network
Knecht
The quest for an unhackable quantum internet is not confined to New York City. Numerous metropolitan quantum networks are emerging globally, including those in Hefei, China, and Chicago, Illinois. However, challenges remain, particularly in addressing the loss of photons over extensive distances.
Namazi emphasizes that quantum entanglement could have immediate applications. By integrating entangled photons into classical light streams, malicious interception attempts can be detected, serving as a quantum tripwire.
Another practical use is authenticating the identity of individuals exchanging sensitive information based on their location. Collaborating with Alexander Gaeta at Columbia University, Qunnect is actively exploring these capabilities. In a single New York borough, numerous financial institutions could significantly benefit from such advancements, as indicated by Javad Shabani at New York University. “Once the infrastructure is established, the demand will follow, probably from just across the street.”
While the quantum internet is still in its infancy, I was impressed by the extent of operational technology during my drive from Qunnect’s headquarters to QTD’s data center. As I crossed one of New York’s bridges, I pondered the multitude of entangled photons traversing the city—a bustling metropolis with endless potential.
A century ago, the advent of quantum mechanics left physicists gazing into the unknown. Long-held beliefs about reality were called into question. Today, we delve into the enigmatic realm of quantum probability clouds and their peculiar behaviors, even at a distance.
Liminal is a profound installation by artist Pierre Huyghe (featured above) that captures many poignant concepts. Set in Halle am Berghain—formerly an East Berlin power station and now a renowned techno club—this exhibition features immersive video projections and soundscapes that resonate deeply within the gritty remnants of the concrete structure.
Huyghe’s art emerges from the collapse of atoms transitioning between quantum states, creating soundscapes that reflect the universe’s fundamental language. Some interpretations suggest that reality is not constructed from quantum fields; instead, the quantum state only represents our knowledge, implying that the external world may not truly exist. Huyghe’s depiction of faceless figures intertwined with the landscape powerfully encapsulates this concept, transcending simplistic explanations.
Sure! Here’s a rewritten version of the content, optimized for SEO while retaining the HTML tags:
Adam Weiss of SEEQC, the pioneering quantum chip manufacturing company.
SEEQC
<p>Explore the remarkable innovations of the 1980s, from British heavy metal to vibrant purple blush favored by makeup artists. Yet, amid the glam and flair, a neglected technological gem emerged: superconducting circuits. In 1980, IBM invested in this revolutionary technology to create highly efficient computers, showcasing a superconducting circuit on the cover of <em>Scientific American</em> during the same year.</p>
<p>However, the anticipated revolution never materialized, and superconducting chips faded into obscurity, much like perms and pegged pants. Yet, one company persevered in its research efforts—SEEQC. I recently toured SEEQC's cutting-edge quantum chip manufacturing facility in upstate New York, born from IBM's discontinued superconducting computing program. Here, I discovered SEEQC's aspirations for superconducting chips in ushering a new era in quantum computing.</p>
<p>Inside the SEEQC facility, you’re greeted by extensive machinery and technicians donned in protective gear. In cleanrooms, ultra-thin layers of niobium, a superconducting metal, are meticulously deposited onto dielectric materials, forming intricate, sandwich-like structures. Lithographic devices further refine these structures, carving out tiny trenches essential for quantum processes. The atmosphere buzzes with activity, illuminated in yellow light to minimize disruption during chip production. In a conference room, SEEQC's CEO <a href="https://seeqc.com/about/leadership/john-levy">John Levy</a> presented a superconducting chip that is surprisingly compact yet poised to transform this futuristic industry.</p>
<h2>The Challenge Ahead</h2>
<p>Superconductors excel at delivering electricity with flawless efficiency, distinguishing them from conventional electronic materials. For instance, when charging a phone, heat loss in cords and chargers often reduces effectiveness. In a 2017 study by computer scientists, they noted traditional computers often function as costly electric heaters, performing minimal calculations alongside unnecessary energy loss.</p>
<p>Comparatively, superconducting computers eliminate this efficiency problem. However, a significant limitation exists: all known superconductors require extremely low temperatures or immense pressure to function. This necessity has historically rendered superconducting computing prohibitively expensive and impractical. IBM abandoned its superconducting computing research in 1983, leading to a preference for traditional overheating computers. Ironically, energy costs have surged recently, especially due to the growing demand from AI technologies.</p>
<p>A shift occurred in the late 1990s when a team of Japanese researchers <a href="https://arxiv.org/pdf/cond-mat/9904003">created</a> the first superconducting qubit, a foundational element of quantum computing. This innovative approach diverged from prior attempts, paving the way for a new computing paradigm leveraging processes unique to quantum mechanics.</p>
<p>Since then, superconducting qubits have powered significant advancements in quantum computing. Tech giants like Google and IBM utilize this technology to tackle complex scientific challenges, achieving remarkable demonstrations of "quantum supremacy" that underline the distinct capabilities of quantum computers compared to classical counterparts.</p>
<p>However, true disruptive technologies in quantum computing remain elusive. Quantum computers have yet to realize their potential to revolutionize areas such as cryptography or industrial chemistry, with numerous technical and engineering challenges lying ahead.</p>
<p>SEEQC's Levy believes some solutions could trace back to the 1980s. His team is developing digital superconducting chips designed to enhance the power, size, and error resilience of quantum computers simultaneously. Nearby, researchers are busy testing chips in various refrigerator configurations, aiming to streamline quantum computing components, ultimately enhancing efficiency.</p>
<p>The working core of a superconducting quantum computer comprises a chip packed with qubits and a refrigerator essential for their operation. Externally, it appears as a single, elongated box comparable in height to a person. However, the components extend beyond this simple design. Control mechanisms, traditional computational inputs, and output readings from quantum calculations require elaborate setups. Moreover, qubits are delicate and susceptible to errors, necessitating sophisticated control systems for real-time monitoring and adjustments. This means non-quantum components, which consume substantial space and energy, play a crucial role in the overall functionality of quantum computers.</p>
<p>Expanding qubit numbers to enhance computational power necessitates additional cables. “Physically, you can't keep adding cables forever,” asserts <a href="https://seeqc.com/about/leadership/shu-jen-han-phd">Shu Zhen Han</a>, SEEQC's Chief Technology Officer. Each new cable introduces heat that disrupts qubits and affects their performance. While this might seem purely technical, the complexities of connecting and controlling qubits represent significant hurdles for quantum computing advancement.</p>
<p>The SEEQC chip I examined addresses many of these challenges.</p>
<p>
<figure class="ArticleImage">
<div class="Image__Wrapper">
<img class="Image" alt="SEEQC quantum chip"
width="1350" height="899"
src="https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg"
srcset="https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=300 300w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=400 400w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=500 500w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=600 600w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=700 700w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=800 800w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=837 837w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=900 900w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1003 1003w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1100 1100w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1200 1200w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1300 1300w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1400 1400w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1500 1500w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1600 1600w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1674 1674w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1700 1700w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1800 1800w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=1900 1900w, https://images.newscientist.com/wp-content/uploads/2026/02/24002912/SEI_283782774.jpg?width=2006 2006w"
sizes="(min-width: 1288px) 837px, (min-width: 1024px) calc(57.5vw + 55px), (min-width: 415px) calc(100vw - 40px), calc(70vw + 74px)"
loading="lazy" data-image-context="Article"
data-image-id="2516803"
data-caption="SEEQC's quantum chip"
data-credit="Karmela Padavic-Callaghan"/>
</div>
<figcaption class="ArticleImageCaption">
<div class="ArticleImageCaption__CaptionWrapper">
<p class="ArticleImageCaption__Title">SEEQC Quantum Chip</p>
<p class="ArticleImageCaption__Credit">Carmela Padavic-Callaghan</p>
</div>
</figcaption>
</figure>
</p>
<p>The SEEQC chip embodies the typical design of a computer chip: small, flat, with a metal rectangle atop a larger one. Levy explained that the smaller rectangle holds superconducting qubits, while the larger one is a conventional chip of superconducting material, facilitating digital control of the qubits. Since both components are superconducting, they can occupy the same refrigerator, reducing the reliance on many energy-consuming room-temperature devices.</p>
<p>This innovation not only prevents excess heat from impacting the refrigerator's performance but also significantly lowers power consumption of the control chip. SEEQC predicts that their quantum computers could achieve an energy efficiency increase by a factor of one billion. The Quantum Energy Initiative says certain designs of ultra-reliable quantum computers could, paradoxically, consume more energy than current large-scale supercomputers, much of which stems from traditional computing components.</p>
<p>Additionally, by integrating the quantum and classical chips, instruction delays to the qubits and result readings are minimized. Levy mentioned that the digital signals from the chip reduce "crosstalk" and unintended interactions, making the qubits less prone to errors.</p>
<p>In discussions I had in 2025 with David DiVincenzo, who proposed seven essential conditions for viable quantum computer creation two decades ago, it remains a blueprint guiding researchers today. He envisioned a future where powerful quantum computers, potentially comprising a million qubits, would occupy expansive spaces resembling particle colliders rather than traditional computing setups. SEEQC’s mission aims to mitigate this expansive future, striving for a compact design reminiscent of a modern Mac rather than the bulky ENIAC.</p>
<p>Currently, SEEQC is testing its chip across varied configurations, employing qubits sourced both in-house and from other quantum manufacturers. Early performance assessments are promising, indicating the chip's versatility, though initial tests have been limited to fewer than 10 qubits, considerably smaller than the envisaged powerful quantum computers.</p>
<p>Physics challenges also emerge, as superconductors can experience tiny quantum vortices when exposed to nearby magnetic fields used for tuning qubits. <a href="https://seeqc.com/about">Oleg Mukhanov</a>, SEEQC’s Chief Scientific Officer, shared insights on a novel method developed by the company to eliminate these vortices using an opposing electromagnetic field. It reminded me of my graduate studies in superconductivity physics: even pioneering technology cannot evade the fundamental quirks of quantum mechanics.</p>
<p>Will superconducting circuits make a triumphant return and push us into a quantum renaissance? It seems the '80s might be making a comeback in the quantum realm—though I hope the oversized shoulder pads don't follow suit.</p>
<section class="ArticleTopics" data-component-name="article-topics">
<p class="ArticleTopics__Heading">Topics:</p>
</section>
SEO Optimization Notes:
Heading Tags: Kept a clear hierarchy with an H2 tag for major sections.
Image Alt Text: Provided descriptive alt text for images to enhance accessibility and searchability.
Internal Links: Maintained existing links to relevant sources for authority and trustworthiness.
Keyword Use: Enhanced usage of relevant keywords like “superconducting circuits,” “quantum computing,” and “energy efficiency” for better search engine ranking.
Engagement: Encouraged engagement with informative and captivating language throughout the text.
Recent advancements in quantum computing have decreased the power required to breach standard encryption techniques by tenfold. With this remarkable reduction, common encryption methods face heightened vulnerability, prompting concerns about future security.
The RSA algorithm, a staple in online banking and secure communications, relies on the intricate task of factoring two large prime numbers. While the possibility of using quantum computers to bypass this challenge was theorized since the 1990s, the physical size requirements of such quantum systems previously rendered them impractical.
However, this landscape is shifting. In a groundbreaking 2019 study, Craig Gidney, from Google’s Quantum AI, outlined a method that significantly lowered this requirement from 170 million qubits to just 20 million. Furthermore, by 2025, Gidney plans to bring it down to below one million qubits. Most recently, Paul Webster and his Australian team at Iceberg Quantum cut this estimate to approximately 100,000 qubits.
Their research expands on Gidney’s algorithm improvements while incorporating a new methodology called qLDPC coding, which enhances qubit connectivity beyond immediate neighbors. This modification increases the overall information density possible in quantum systems.
Based on their findings, the team predicts that cracking a prevalent RSA encryption could become feasible within about a month using 98,000 superconducting qubits—those presently manufactured by tech giants like IBM and Google. To achieve this in just one day, a staggering 471,000 qubits would be necessary.
Some quantum computing firms aspire to develop machines with hundreds of thousands of qubits within the next decade. However, these optimistic calculations overlook material considerations and focus primarily on error rates and computational speed. What happens if the Iceberg Quantum approach is feasible? An entity controlling such a quantum computer could potentially access private emails, bank accounts, and governmental data secured via RSA encryption.
“The stringent requirements pose a significant challenge in hardware manufacturing—the toughest hurdle,” Gidney comments. Similarly, Scott Aaronson from the University of Texas at Austin expressed concerns about the practicalities of configuring connections between distant qubits on his blog here.
IBM has been an advocate for qLDPC coding recently, making strides in making its quantum hardware compatible. However, the extent of success with this methodology remains uncertain. An IBM spokesperson noted that qLDPC codes form the “foundation” of their quantum computing technology but did not elaborate on the feasibility of Iceberg’s innovations.
Facilitating connections between distant qubits is simpler when using extremely cold atoms or ions—two emerging strategies in the quantum computing arena. Yet these systems are often slower, and recent research indicates that unlocking RSA encryption may still require millions of qubits.
“It’s crucial to maintain a flexible perspective on the timeline for such breakthroughs,” states Lawrence Cohen from Iceberg Quantum. “Should RSA be compromised, the fallout could be immense. It’s better to be proactive than reactive.”
Although breaking RSA encryption is a well-researched issue, it serves as an excellent benchmark for those pursuing powerful quantum systems. Moreover, the team’s techniques might also enhance simulations of quantum materials and quantum chemistry.
In the realm of quantum mechanics, the principle of no duplication for quantum information is considered an unbreakable rule. However, a novel technique for backing up qubits—the fundamental units of quantum computers—may potentially challenge this foundational aspect of physics.
Initially identified in the 1980s, the no-cloning theorem asserts that a quantum state, which encapsulates all information about a quantum system, cannot be duplicated. Attempts to copy this information typically compromise the fragility of the quantum properties being assessed. This principle is crucial for advancements in quantum technologies, including cryptography, enabling secure communication protocols that effectively prevent information duplication and interception.
Researchers from the University of Waterloo in Canada have introduced an unexpected breakthrough: the ability to clone a quantum system, provided the information is encrypted and accompanied by a unique one-time decryption key.
Achim Kemp states, “This method allows for the creation of numerous copies to enhance redundancy, yet all copies must remain encrypted, and each decryption key may only be utilized once.” This compliance with the no-cloning theorem assures that only a singular, unambiguous, readable copy of a qubit exists at any point.
Through an exploration of how quantum Wi-Fi and radio stations could function, Kemp and his team stumbled upon this astonishing revelation. Traditional no-cloning principles would inhibit multiple receivers from accessing identical quantum information.
While delving into the impact of random fluctuations and noise on information copying, the team discerned that these disturbances might inadvertently undermine the no-cloning theorem, prompting the question, “Why does quantum noise seem to confuse the no-cloning theorem?”
Upon thorough investigation, they concluded that noise could inadvertently serve as an encryption mechanism, disrupting the original signal, yet remaining reversible. When utilized intentionally, this phenomenon can act as a tool for secure information dissemination.
After validating this concept theoretically, the team successfully implemented the protocol on an actual IBM Heron 156-qubit quantum computing processor.
This innovative approach exhibits a level of resilience against the errors and noise characteristic of contemporary quantum computers, enabling the production of hundreds of encrypted clones of a single qubit. “In fact, we maximized our capacity on the IBM processor. Despite housing only 156 qubits, we estimated we could produce over 1,000 clones before triggering error messages,” Kemp explains.
This advancement to the no-cloning theorem holds promise for the future of quantum cloud storage and computing services. “Similar to how Dropbox ensures a file’s safety by storing it across three distinct geographical servers, this method offers a viable solution for duplicating quantum data,” Kemp adds.
Alex Kissinger from the University of Oxford remarks, “It’s a fascinating quantum cryptographic protocol with ample potential in quantum communications, where redundancy in transmitted information can be invaluable.” However, he emphasizes that this technique should not be misconstrued as cloning. “It signifies a method of dissemination rather than replication,” Kissinger clarifies. “It’s about distributing information so that one recipient can later retrieve it.”
Kemp concurs, asserting, “This isn’t cloning; it’s encrypted cloning—merely a refinement of the no-duplication theorem.”
Time crystals present a remarkable concept in quantum physics. New research indicates that these intriguing materials could play a pivotal role in the development of ultra-accurate clocks.
All crystals are characterized by a repeating structure. Traditional crystals consist of atoms organized in a repeated pattern, while time crystals exhibit structures that repeat over time. Observing a time crystal reveals a consistent repetition of configurations. This cyclical behavior occurs naturally, not because the material is forced, but because it represents its lowest energy state, much like ice is the stable phase of cold water.
Ludmila Viotti and a team from Italy’s Abdus Salam International Center for Theoretical Physics have demonstrated that time crystals could serve as excellent components for precise quantum timekeeping devices.
The researchers performed a mathematical analysis of systems with up to 100 quantum mechanical particles. Each particle displayed two states defined by its quantum spin properties, akin to how a coin has two sides. The specific spin system they investigated can exist as either a time crystal or a conventional phase that lacks spontaneous time oscillation, providing potential for clock functions in either form. The study compared the accuracy of timekeeping using spins in both the time crystal and normal phases.
As Viotti explains, “In the normal phase, seeking finer temporal resolutions results in exponentially decreased accuracy. However, the time crystal phase offers significantly improved precision at the same resolution.” For instance, standard spin-based clocks tend to lose accuracy when measuring seconds over minutes, a challenge that could be mitigated with time crystal configurations.
Mark Mitchison, a researcher at King’s College London, acknowledges the promising applications of time crystals in horology but notes that rigorous evaluations of their advantages have been scarce. His research group has previously established that random sequences can function as clocks. However, systems that maintain self-sustaining oscillations inherently possess a more clock-like nature.
“While time crystals have been theorized for nearly a decade, the methods to utilize them remain unclear,” remarks Krzysztof Sasha from Jagiellonian University in Poland. “Just as regular crystals find diverse applications in both jewelry and computing, we anticipate that time crystals will pave the way for similarly innovative technologies.”
While time crystals may not surpass the accuracy of today’s leading atomic clocks, they could offer viable alternatives to satellite-based timekeeping systems like GPS, which are vulnerable to interference. Additionally, clocks based on time crystals may lay the foundation for sensitive magnetic field sensors, as minor magnetic disruptions can affect clock performance, according to Mitchison.
Despite the potential, Viotti emphasizes that extensive research is needed before practical implementation. She indicates that their spin system should undergo comparisons with other accurate clock systems and require experimental validation involving real spins.
Have you ever noticed how a forgotten cup of coffee cools down as it releases heat to the surrounding air? In the fascinating world of quantum mechanics, this process can actually be reversed. This surprising finding suggests that the second law of thermodynamics—which posits that heat flows from hot to cold—might require reevaluation.
Dawei Lu, a part of a research team from Southern University of Science and Technology in China, challenges conventional physics by exploring this thermodynamic phenomenon using crotonic acid molecules, which are made of carbon, hydrogen, and oxygen. The team utilized the nuclei of four carbon atoms as qubits, the fundamental units of quantum computers that store quantum information. Unlike traditional computations that use electromagnetic radiation to control qubit states, the researchers directed heat from cooler qubits to hotter ones.
Such a reversal would be impossible in our everyday experiences, like the cooling of coffee, which needs additional energy to achieve what is termed heat regurgitation. However, in the quantum realm, fuel in the form of quantum information—specifically “coherence”—is available. As Lu explains, “By injecting and manipulating this quantum information, we can reverse the normal direction of heat flow. Exciting times indeed.”
Interestingly, the breakdown of thermodynamic laws in quantum mechanics isn’t entirely unexpected. The second law was formulated in the 19th century, long before quantum physics took its place in scientific discourse. To address this inconsistency, Lu and his colleagues derived an “apparent temperature” for each qubit, a reinterpretation of classical temperature that accommodates quantum properties like coherence. This leads to the reaffirmation that thermal energy indeed flows from a higher apparent temperature to a lower one, aligning with established thermodynamic principles.
In a related system, Roberto Serra from Brazil’s ABC Federal University emphasizes that quantum properties such as coherence act as a thermodynamic resource—akin to how heat powers a steam engine. By manipulating these quantum resources, researchers can intentionally breach the classical laws of thermodynamics. “Traditional thermodynamic laws were conceived without considering our access to such microscopic states, revealing a need for new theoretical frameworks,” Serra points out.
The team aspires to adapt their thermal inversion experiments into practical techniques for regulating heat between qubits. Lu envisions that mastering the relationship between quantum information and thermal management could significantly enhance quantum computing capabilities. This advancement holds pivotal implications for the expanding field of quantum technologies, especially since conventional computers face severe limitations due to overheating issues.
Sure! Here’s the SEO-optimized version of the content while retaining the original HTML structure:
Quantum batteries are making their debut in quantum computers, paving the way for future quantum technologies. These innovative batteries utilize quantum bits, or qubits, that change states, differing from traditional batteries that rely on electrochemical reactions.
Research indicates that harnessing quantum characteristics may enable faster charging times, yet questions about the practicality of quantum batteries remain. “Many upcoming quantum technologies will necessitate quantum versions of batteries,” states Dian Tan from Hefei National Research Institute, China. “While significant strides have been made in quantum computing and communication, the energy storage mechanisms in these quantum systems require further investigation.”
Tan and his team constructed the battery using 12 qubits formed from tiny superconducting circuits, controlled by microwaves. Each qubit functioned as a battery cell and interacted with neighboring qubits.
The researchers tested two distinct charging protocols, one mirroring conventional battery charging without quantum interactions, while the other leveraged quantum interactions. They discovered that exploiting these interactions led to an increase in power and a quicker charging capacity.
“Quantum batteries can achieve power output up to twice that of conventional charging methods,” asserts Alan Santos from the Spanish National Research Council. This compatibility with the nearest neighbor interaction of qubits is notable, as this is typical for superconducting quantum computers, making further engineering of beneficial interactions a practical challenge.
James Quach from Australia’s Commonwealth Scientific and Industrial Research Organisation adds that previous quantum battery experiments have utilized molecules rather than components in current quantum devices. Quach and his team have theorized that quantum batteries may enhance the efficiency and scalability of quantum computers, potentially becoming the power source for future quantum systems.
However, comparing conventional and quantum batteries remains a complex task, notes Dominik Shafranek from Charles University in the Czech Republic. In his opinion, translating the advantages of quantum batteries into practical applications is currently ambiguous.
Kaban Modi from the Singapore University of Technology and Design asserts that while benefits exist for qubits interfacing exclusively with their nearest neighbors, their research indicates these advantages can be negated by real-world factors like noise and sluggish qubit control.
Additionally, the burgeoning requirements of extensive quantum computers may necessitate researching energy transfer within quantum systems, as they might incur significantly higher energy costs compared to traditional computers, Modi emphasizes.
Tan believes that energy storage for quantum technologies, particularly in quantum computers, is a prime candidate for their innovative quantum batteries. Their next goal involves integrating these batteries with qubit-based quantum thermal engines to produce energy for storage within quantum systems.
Artist Representation of Qubits in the Quantum Twins Simulator
Silicon Quantum Computing
A groundbreaking large-scale quantum simulator has the potential to unveil the mechanisms of exotic quantum materials and pave the way for their optimization in future applications.
Quantum computers are set to leverage unique quantum phenomena to perform calculations that are currently unmanageable for even the most advanced classical computers. Similarly, quantum simulators can aid researchers in accurately modeling materials and molecules that remain poorly understood.
This holds particularly true for superconductors, which conduct electricity with remarkable efficiency. The efficiency of superconductors arises from quantum effects, making it feasible to implement their properties directly in quantum simulators, unlike classical devices that necessitate extensive mathematical transformations.
Michelle Simmons and her team at Australia’s Silicon Quantum Computing have successfully developed the largest quantum simulator to date, known as Quantum Twin. “The scale and precision we’ve achieved with these simulators empower us to address intriguing challenges,” Simmons states. “We are pioneering new materials by crafting them atom by atom.”
The researchers designed multiple simulators by embedding phosphorus atoms into silicon chips. Each atom acts as a quantum bit (qubit), the fundamental component of quantum computers and simulators. The team meticulously configured the qubits into grids that replicate the atomic arrangement found in real materials. Each iteration of the Quantum Twin consisted of a square grid containing 15,000 qubits, surpassing any previous quantum simulator in scale. While similar configurations have been built using thousands of cryogenic atoms in the past, Quantum Twin breaks new ground.
By integrating electronic components into each chip via a precise patterning process, the researchers managed to control the electron properties within the chips. This emulates the electron behavior within simulated materials, crucial for understanding electrical flow. Researchers can manipulate the ease of adding an electron at specific grid points or the “hop” between two points.
Simmons noted that while conventional computers struggle with large two-dimensional simulations and complex electron property combinations, the Quantum Twin simulator shows significant potential for these scenarios. The team tested the chip by simulating the transition between conductive and insulating states—a critical mathematical model explaining how impurities in materials influence electrical conductivity. Additionally, they recorded the material’s “Hall coefficient” across different temperatures to assess its behavior in magnetic fields.
With its impressive size and variable control, the Quantum Twins simulator is poised to tackle unconventional superconductors. While conventional superconductors function well at low temperatures or under extreme pressure, some can operate under milder conditions. Achieving a deeper understanding of superconductors at ambient temperature and pressure is essential—knowledge that quantum simulators are expected to furnish in the future.
Moreover, Quantum Twins can also facilitate the investigation of interfaces between various metals and polyacetylene-like molecules, holding promise for advancements in drug development and artificial photosynthesis technologies, Simmons highlights.
One of the most paradoxical aspects of science is how we can delve into the universe’s deepest enigmas, like dark matter and quantum gravity, yet trip over basic concepts. Nobel laureate Richard Feynman once candidly admitted his struggle to grasp why mirrors flip images horizontally instead of vertically. While I don’t have Feynman’s challenges, I’ve been pondering the fundamental concept of temperature.
Since time immemorial, from the earliest humans poking fires to modern scientists, our understanding of temperature has dramatically evolved. The definition continues to change as physicists explore temperature at the quantum level.
My partner once posed a thought-provoking question: “Can a single particle possess a temperature?” While paraphrased, this inquiry challenges conventional wisdom.
His instinct was astute. A single particle cannot possess a temperature. Most science enthusiasts recognize that temperature applies to systems comprising numerous particles—think gas-filled pistons, coffee pots, or stars. Temperature is essentially an average energy distribution across a system reaching equilibrium.
Visualize temperature as a ladder, each rung representing energy levels. The more rungs, the greater the energy. For a substantial number of particles, we expect them to occupy various rungs, with most clustering at lower levels and some scaling higher ones. The distribution gradually tapers off as energy increases.
But why use this definition? While averages are helpful, one could argue the average height in a room with one tall person could misleadingly imply everyone else is six feet tall. Why not apply the same logic to temperature?
Temperature serves a predictive role, not merely a descriptive one. In the 17th and 18th centuries, as researchers strove to harness the potential of fire and steam, temperature became pivotal in understanding how different systems interacted.
This insight led to the establishment of the 0th law of thermodynamics—the last yet most fundamental principle. It states that if a thermometer registers 80°C for warm water and the same for warm milk, there should be no net heat exchange when these two are mixed. Though seemingly simple, this principle forms the basis for classical temperature measurements.
This holds true due to the predictable behavior of larger systems. Minute energy variances among individual particles become negligible, allowing statistical laws to offer broad insights.
Thermodynamics operates differently than Isaac Newton’s laws of motion, which apply universally regardless of how many objects are involved. Thermodynamic laws arise only in larger systems where averages and statistical regularities emerge.
Thus, a single particle lacks temperature—case closed.
Or so I believed until physics threw another curveball my way. In many quantum systems, composed of a few particles, stable properties often evade observation.
In small systems like individual atoms, states can become trapped and resist reaching equilibrium. If temperature describes behavior after equilibrium, does this not challenge its very definition?
What exactly is temperature?
fhm/Getty Images
Researchers are actively redefining temperature from the ground up, focusing on its implications in the quantum realm.
In a manner akin to early thermodynamics pioneers, contemporary scientists are probing not just what temperature is, but rather what it does. When a quantum system interacts with another, how does heat transfer? Can it warm or cool its neighbor?
In quantum systems, both scenarios are possible. Consider the temperature ladder for particles. In classical physics, heat always moves from a system with more particles to one with fewer, following predictable rules.
Quantum systems defy these conventions. It’s common for no particles to occupy the lowest rung, with all clustered around higher energy levels. Superposition allows particles to exist in between. This shift means quantum systems often do not exhibit traditional thermal order, complicating heat flow predictions.
To tackle this, physicists propose assigning two temperatures to quantum systems. Imagine a reference ladder representing a thermal system. One temperature indicates the highest rung from which the system can absorb heat, while the other represents the lowest rung to which it can release heat. This new framework enables predictable heat flow patterns outside this range, while outcomes within depend on the quantum system’s characteristics. This new “Zero Law of thermodynamics” helps clarify how heat moves in quantum domains.
These dual temperatures reflect a system’s capacity to exchange energy, regardless of its equilibrium state. Crucially, they’re influenced by both energy levels and their structural arrangement—how quantum particles distribute across energy levels and the transitions the overall system can facilitate.
Just as early thermodynamicists sought functionality, quantum physicists are likewise focused on applicability. Picture two entangled atoms. Changes in one atom will affect the other due to their quantum link. When exposed to external conditions, as they gain or lose energy, the invisible ties connecting them create a novel flow of heat—one that can be harnessed to perform work, like driving quantum “pistons” until the entanglement ceases. By effectively assigning hot and cold temperatures to any quantum state, researchers can determine ideal conditions for heat transfer, powering tasks such as refrigeration and computation.
If you’ve followed along up to this point, here’s my confession: I initially argued that a single particle could have temperature, though my partner’s intuition was spot on. In the end, we realized both perspectives hold some truth—while a single particle can’t be assigned a traditional temperature, the concept of dual temperatures in quantum systems offers intriguing insights.
John Martinis is a leading expert in quantum hardware, who emphasizes hands-on physics rather than abstract theories. His pivotal role in quantum computing history makes him indispensable to my book on the subject. As a visionary, he is focused on the next groundbreaking advancements in the field.
Martinis’s journey began in the 1980s with experiments that pushed the limits of quantum effects, earning him a Nobel Prize last year. During his graduate studies at the University of California, Berkeley, he tackled the question of whether quantum mechanics could apply to larger scales, beyond elementary particles.
Collaborating with colleagues, Martinis developed circuits combining superconductors and insulators, demonstrating that multiple charged particles could behave like a single quantum entity. This discovery initiated the macroscopic quantum regime, forming the backbone of modern quantum computers developed by giants like IBM and Google. His work led to the adoption of superconducting qubits, the most common quantum bits in use today.
Martinis made headlines again when he spearheaded a team at Google that built the first quantum computer to achieve quantum supremacy. For nearly five years, this machine could independently verify the outputs of random quantum circuits, though it was eventually surpassed by classical computers in performance.
Approaching seven decades of age, Martinis still believes in the potential of superconducting qubits. In 2024, he co-founded QoLab, a quantum computing startup proposing revolutionary methodologies aimed at developing a genuinely practical quantum computer.
Carmela Padavich Callahan: Early in your career, you fundamentally impacted the field. When did you realize your experiments could lead to technological advancements?
John Martinis: I questioned whether macroscopic variables could bypass quantum mechanics, and as a novice in the field, I felt it was essential to test this assumption. A fundamental quantum mechanics experiment intrigued me, even though it initially seemed daunting.
Our first attempt was a simple and rapid experiment using contemporary technology. The outcome was a failure, but I quickly pivoted. Learning about microwave engineering, we tackled numerous technical challenges before achieving subsequent successes.
Over the next decade, our work on quantum devices laid a solid foundation for quantum computing theory, including the breakthrough Scholl algorithm for factorizing large numbers, essential for cryptography.
How has funding influenced research and the evolution of technology?
Since the 1980s, the landscape has transformed dramatically. Initially, there was uncertainty about manipulating single quantum systems, but quantum computing has since blossomed into a vast field. It’s gratifying to see so many physicists employed to unravel the complexities of superconducting quantum systems.
Your involvement during quantum computing’s infancy gives you a unique perspective on its trajectory. How does that inform your current work?
Having long experience in the field, I possess a deep understanding of the fundamentals. My team at UC Santa Barbara developed early microwave electronics, and I later contributed to foundational cooling technology at Google for superconducting quantum computers. I appreciate both the challenges and opportunities in scaling these complex systems.
Cryostat for Quantum Computers
Mattia Balsamini/Contrasto/Eyeline
What changes do you believe are necessary for quantum computers to become practical? What breakthroughs do you foresee on the horizon?
After my tenure at Google, I reevaluated the core principles behind quantum computing systems, leading to the founding of QoLab, which introduces significant changes in qubit design and assembly, particularly regarding wiring.
We recognized that making quantum technology more reliable and cost-effective requires a fresh perspective on the construction of quantum computers. Despite facing skepticism, my extensive experience in physics affirms that our approach is on the right track.
It’s often stated that achieving a truly functional, error-free quantum computer requires millions of qubits. How do you envision reaching that goal?
The most significant advancements will arise from innovations in manufacturing, particularly in quantum chip fabrication, which is currently outdated. Many leading companies still use techniques reminiscent of the mid-20th century, which is puzzling.
Our mission is to revolutionize the construction of these devices. We aim to minimize the chaotic interconnections typically associated with superconducting quantum computers, focusing on integrating everything into a single chip architecture.
Do you foresee a clear leader in the quest for practical quantum computing in the next five years?
Given the diverse approaches to building quantum computers, each with its engineering hurdles, fostering various strategies is valuable for promoting innovation. However, many projects do not fully contemplate the practical challenges of scaling and cost control.
At QoLab, we adopt a collaborative business model, leveraging partnerships with hardware companies to enhance our manufacturing capabilities.
If a large-scale, error-free quantum computer were available tomorrow, what would your first experiment be?
I am keen to apply quantum computing solutions to challenges in quantum chemistry and materials science. Recent research highlights the potential for using quantum computers to optimize nuclear magnetic resonance (NMR) experiments, as classical supercomputers struggle with such complex quantum issues.
While others may explore optimization or quantum AI applications, my focus centers on well-defined problems in materials science, where we can craft concrete solutions with quantum technologies.
Why have mathematically predicted quantum applications not materialized yet?
While theoretical explorations in qubit behavior are promising, real-life qubits face significant noise challenges, making practical implementations far more complex. Theoretical initiatives comprehensively grasp theory but often overlook the intricacies of hardware development.
Through my training with John Clark, I cultivated a strong focus on noise reduction in qubits, which has proven beneficial in experiments showcasing quantum supremacy. Addressing these challenges requires dedication to understanding qubit design intricacies.
As we pursue advancements, a dual emphasis on hardware improvements and application innovation remains crucial in the journey to unlock quantum computing’s full potential.
Beyond Quantum Anthony Valentini, Oxford University Press
Physics is experiencing unexpected challenges. Despite extensive research, the elusive dark matter remains undetected, while the Higgs boson’s discovery hasn’t clarified our path forward. Moreover, string theory, often hailed as the ultimate theory of everything, lacks solid, testable predictions. This leaves us pondering: what’s next?
Recently, many physicists and science writers have shied away from addressing this question. While they used to eagerly anticipate groundbreaking discoveries, they now often revert to philosophical musings or reiterate known facts. However, Antony Valentini from Imperial College London stands out. In his book, Beyond Quantum: Exploring the Origins and Hidden Meanings of Quantum Mechanics, he introduces bold, innovative ideas.
The book’s focus is quantum mechanics, a pillar of physics for the last century. This field hinges on the concept of the wave function—a mathematical representation capable of detailing the complete state of any system, from fundamental particles to larger entities like us.
The enigma of wave functions is their tendency not to describe ordinary localized objects but rather a diffuse, fuzzy version of them. Upon observation, the wave function “collapses” into a random outcome with probabilities defined by Born’s law, a principle established by physicist Max Born, typically covered in academic literature. This results in objects manifesting with clear attributes in specific locations.
The debate surrounding the interpretation of the wave function has persisted, with two primary perspectives emerging. One posits that wave functions represent reality itself, suggesting that electrons, cats, and humans exist in multiple states simultaneously across time and space—a many-worlds interpretation fraught with metaphysical implications.
“
Pilot wave theory has long been known to reproduce all the predictions of quantum mechanics. “
The alternative interpretation suggests that wave functions are not the entirety of reality. This is where pilot wave theory, significantly advanced by Valentini and initially proposed by Louis de Broglie in 1927, comes into play.
Louis de Broglie: Pioneer of Pilot Wave Theory
Granger – Historical Photo Archive/Alamy
Pilot wave theory posits a real yet incomplete wave function, suggesting the wave guides individual particles instead of being mere waves influencing a floating plastic bottle. In this model, particles remain specific, and their wave-like behavior originates from the pilot wave itself.
This theory has consistently validated all quantum mechanics predictions, eschewing fundamental randomness. However, Valentini underscores that this agreement rests on the assumption that particles maintain equilibrium with waves, which aligns with current experimental data but isn’t universally applicable.
Valentini’s hypothesis suggests that in the universe’s infancy, particles existed far from quantum equilibrium before settling into their current states, akin to a cup of coffee cooling down. In this scenario, the Born rule and its inherent randomness morph from core natural features into historical anomalies shaped by cosmology.
Moreover, quantum randomness also hinders the practical utilization of nonlocality, implicating direct interactions between separate objects across time and space. Valentini argues that if the Born law had not prevailed in the universe’s early stages, instantaneous communication across vast distances may have occurred, potentially leaving traces on the cosmic microwave background. If any relics from that era exist, superluminal signal transmission might still be feasible.
Though Valentini’s insights might appear speculative without concrete evidence, his rigorous examination of how conventional quantum mechanics became dominant makes his work noteworthy. While there could be gaps, especially in clearly explaining the pilot wave aspect, Valentini’s contributions illuminate what a ‘big idea’ looks like in a field rife with uncertainty.
Victor de Schwanberg/Science Photo Library/Getty Images
From the perspective of quantum physics, the universe may be fundamentally agnostic in some respects.
In quantum physics, every object, such as an electron, corresponds to a mathematical entity known as a wave function. This wave function encodes all details regarding an object’s quantum state. By combining the wave function with other equations, physicists can effectively predict the behavior of objects in experiments.
If we accept that the entire universe operates on quantum principles, then even larger entities, including the cosmos itself, must possess a wave function. This perspective has been supported by iconic physicists like Stephen Hawking.
However, researchers like Eddie Kemin Chen from the University of California, San Diego and Roderich Tumulka from the University of Tübingen in Germany, have demonstrated that complete knowledge of the universal wave function may be fundamentally unattainable.
“The cosmic wave function is like a cosmic secret that physics itself conspires to protect. We can predict a lot about how the universe behaves, yet we remain fundamentally unsure of its precise quantum state,” states Chen.
Previous studies assumed specific forms for the universal wave function based on theoretical models of the universe, overlooking the implications of experimental observations. Chen and Tumulka began with a more practical inquiry: Can observations help in identifying the correct wave function among those that reasonably describe our universe?
The researchers utilized mathematical outcomes from quantum statistical mechanics, which examines the properties of collections of quantum states. A significant factor in their calculations was the realization that the universal wave function depends on numerous parameters and exists in a high-dimensional abstract state.
Remarkably, upon completing their calculations, they found that universal quantum states are essentially agnostic.
“The measurements permissible by the rules of quantum mechanics provide very limited insight into the universe’s wave function. Determining the wave function of the universe with significant precision is impossible,” explains Tumulka.
Professor JB Manchak from the University of California, Irvine states that this research enhances our understanding of the limits of our best empirical methods, noting that we essentially have an equivalent to general relativity within the framework of quantum physics. He adds that this should not come as a surprise since quantum theory was not originally designed as a comprehensive theory of the universe.
“The wave function of a small system or the entire universe is a highly theoretical construct. Wave functions are meaningful not because they are observable, but because we employ them,” remarks Sheldon Goldstein from Rutgers University. He further explains that the inability to pinpoint a unique, accurate universal wave function from a limited range of candidates may not be problematic, as any of these functions could yield similar effects in future calculations.
Chen expresses hope to connect his and Tumulka’s research with the exploration of large-scale systems smaller than the universe itself, especially through techniques like shadow tomography, which aim to determine the quantum state of such systems. However, the philosophical consequences of their work are equally crucial. Tumulka emphasizes the need for caution against over-relying on positivist views that deem non-experimental statements as meaningless or unscientific. “Some truths are real, but cannot be measured,” he asserts.
This rationale might influence ongoing debates regarding the interpretation of quantum mechanics. According to Emily Adlam from Chapman University in California, the new findings advocate for incorporating more components into the interpretation of quantum equations, such as wave functions, emphasizing the relationship between quantum objects and individual observer perspectives, moving away from the assumption of a singular objective reality dictated by a single mathematical construct.
Topic:
This revised content is SEO-optimized with relevant keywords and better formatting for improved readability and search engine visibility.
IBM Quantum System Two: The Machine Behind the New Time Crystal Discovery
Credit: IBM Research
Recent advancements in quantum computing have led to the creation of a highly complex time crystal, marking a significant breakthrough in the field. This innovative discovery demonstrates that quantum computers excel in facilitating scientific exploration and novel discoveries.
Unlike conventional crystals, which feature atoms arranged in repeating spatial patterns, time crystals possess configurations that repeat over time. These unique structures maintain their cyclic behavior indefinitely, barring any environmental influences.
Initially perceived as a challenge to established physics, time crystals have been successfully synthesized in laboratory settings over the past decade. Recently, Nicholas Lorente and his team from the Donostia International Physics Center in Spain utilized an IBM superconducting quantum computer to fabricate a time crystal exhibiting unprecedented complexity.
While previous work predominantly focused on one-dimensional time crystals, this research aimed to develop a two-dimensional variant. The team employed 144 superconducting qubits configured in an interlocking, honeycomb-like arrangement, enabling precise control over qubit interactions.
By manipulating these interactions over time, the researchers not only created complex time crystals but also programmed the interactions to exhibit advanced intensity patterns, surpassing the complexity of prior quantum computing experiments.
This new level of complexity allowed the researchers to map the entire qubit system, resulting in the creation of its “state diagram,” analogous to a phase diagram for water that indicates whether it exists as a liquid, solid, or gas at varying temperatures and pressures.
According to Jamie Garcia from IBM, which did not participate in the study, this experiment could pave the way for future quantum computers capable of designing new materials based on a holistic understanding of quantum system properties, including extraordinary phenomena like time crystals.
The model emulated in this research represents such complexity that traditional computers can only simulate it with approximations. Since all current quantum computers are vulnerable to errors, researchers will need to alternate between classical estimation methods and precise quantum techniques to enhance their understanding of complex quantum models. Garcia emphasizes that “large-scale quantum simulations, involving more than 100 qubits, will be crucial for future inquiries, given the practical challenges of simulating two-dimensional systems.”
Biao Huang from the University of the Chinese Academy of Sciences notes that this research signifies an exciting advancement across multiple quantum materials fields, potentially connecting time crystals, which can be simulated with quantum computers, with other states achievable through certain quantum sensors.
In the 1920s, renowned physicist Albert Einstein believed he had identified a fundamental flaw within quantum physics. This led to extensive investigations revealing a pivotal aspect of quantum theory, one of its most perplexing features.
This intriguing property, known as Bell nonlocality, describes how quantum objects exhibit cooperative behavior over vast distances, challenging our intuitions. I’ve accepted this understanding for over 21 years—a remarkable insight for the 21st century.
To illustrate this phenomenon, consider two hypothetical experimenters, Alice and Bob, each possessing a pair of “entangled” particles. Entanglement enables particles to correlate, even when separated by distances that prevent any signal from transmitting between them. Yet, these correlations become apparent only through the interaction of each experimenter with their respective particles. Do these particles “know” about their correlation beforehand, or is some mysterious connection at play?
Einstein, alongside Nathan Rosen and Boris Podolsky, sought to refute this eerie connection. They proposed that certain “local hidden variables” could explain how particles understand their correlated state, making quantum physics more relatable to everyday experiences, where interactions happen at close range.
In the 1960s, physicist John Stewart Bell devised a method to empirically test these concepts. After numerous attempts, groundbreaking experiments in 2015 provided rigorous verification of Bell’s theories, earning three physicists the 2022 Nobel Prize. “This was the final nail in the coffin for these ideas,” says Marek Zhukowski from the University of Gdańsk. Researchers concluded that hidden variables could not maintain the locality of quantum physics. Jacob Valandez at Harvard University adds, “We cannot escape from non-locality.”
Embracing delocality offers substantial advantages, as noted by Ronald Hanson from Delft University of Technology, who led one of the groundbreaking experiments. For him, the focus was never on the oddities of quantum mechanics; rather, he viewed the results as a demonstration of “quantum supremacy” beyond conventional computational capabilities. This intuition proved accurate. The technology developed for the Bell Test has become a foundation for highly secure quantum cryptography.
Currently, Hanson is pioneering quantum communication networks, utilizing entangled particles to forge a near-unhackable internet of the future. Similarly, quantum computing researchers exploit entangled particles to optimize calculations. Although the implications of entanglement remain partially understood, the practical application of entangling quantum objects has transformed into a valuable technological asset, marking a significant evolution for a leading figure in discussions about the quantum nature of reality.
IBM’s Quantum System Two Unveiled at a Data Center in Germany
Quantum computing has been making headlines lately. You might have noticed quantum chips and their intriguing cooling systems dominating your news feed. From politicians to business leaders, the term “quantum” is everywhere. If you find yourself perplexed, consider setting a New Year’s resolution to grasp the fundamentals of quantum computing this year.
This goal may seem daunting, but the timing is perfect. The quantum computing sector has achieved significant breakthroughs lately, making it a hotbed of innovation and investment, with the market expected to exceed $1 billion, likely doubling in the coming years. Yet, high interest often leads to disproportionate hype.
There remain numerous questions about when quantum computers might outpace classical ones. While mathematicians and theorists ponder these queries, the practical route may be to improve quantum computers through experimentation. However, consensus on the best methodologies for building these systems is still elusive.
Compounding the complexity, quantum mechanics itself is notoriously challenging to comprehend. Physicists debate interpretations of bizarre phenomena like superposition and entanglement, which are pivotal for quantum computing’s potential.
Feeling overwhelmed? You’re not alone. But don’t be discouraged; these challenges can be overcome with curiosity.
As a former high school teacher, I often encountered curious students who would linger after class, eager to discuss intricate aspects of quantum computing. Many were novice learners in math or physics, yet they posed thought-provoking questions. One summer, a group who took an online quantum programming course approached me, surpassing my own coding knowledge in quantum applications. The following year, we delved into advanced topics typically reserved for college-level classes.
Recently, I discovered a young talent in quantum inquiry. A 9-year-old YouTuber, Kai, co-hosts a podcast named Quantum Kid, where he interviews leading quantum computing experts for over 88,000 subscribers to enjoy.
Kai’s co-host, Katya Moskvich, is not only his mother but also a physicist with extensive experience in science writing. She works at Quantum Machines, a firm developing classical devices that enhance the functionality of quantum computers. Kai brings an infectious enthusiasm to the podcast, engaging with pivotal figures who have influenced modern quantum theory.
In a recent episode, renowned quantum algorithm creator Peter Scholl discussed the intersection of quantum computing, sustainability, and climate action. Nobel laureate Stephen Chu and distinguished computer scientist Scott Aaronson also joined, exploring concepts like time travel and its theoretical connections to quantum mechanics. Additionally, physicist John Preskill collaborated with roboticist Ken Goldberg to examine the interplay of quantum computing and robotics.
Kai and Co-Host (Mother) Katya Moskvich
While The Quantum Kid may not delve deep into rigorous math, it offers a fun entry point and insight from leading experts in quantum technology. Most episodes introduce fundamental concepts like superposition and Heisenberg’s uncertainty principle, which you can explore further in reputable publications such as New Scientist.
The true strength of The Quantum Kid lies in Kai’s ability to ask the very questions that an inquisitive mind might have regarding quantum computers—those which seek to unpack the complex yet fascinating nature of this technology. If you’ve been curious about quantum computing but have felt overwhelmed, Kai encourages you to remain inquisitive and seek clarity. (We’re here to guide you on your quantum journey.)
Could quantum computers revolutionize space exploration or even facilitate time travel? Might they help develop advanced robotics or combat climate issues? The answers are not straightforward, laden with nuances. Kai’s engaging dialogues make complex theories accessible, ensuring clarity resonates with both young listeners and adults. Hearing Peter Scholl reiterate that current quantum systems lack the clout to change the world doesn’t dampen Kai’s enthusiasm but rather fuels it.
In the pilot episode, physicist Lennart Renner expresses optimism, stating, “We’re evolving alongside new machines that can potentially revolutionize tasks, hence we must deliberate on their applications,” setting a forward-thinking tone that reverberates throughout the series.
Adopting a blend of Kai’s wonder and imagination, coupled with the seasoned expertise of guests, will enhance any quantum learning project you embark on this year. Quantum computing, while intricate and multifaceted, remains incredibly compelling. If your child is captivated, why not explore it together?
As quantum computing technology evolves, it becomes crucial to pinpoint challenges that can be tackled more efficiently than with classical computers. Interestingly, many significant tasks that quantum advocates are pursuing may not necessitate quantum computing at all.
The focal point of this discussion is a molecule called FeMoco, essential for life on Earth due to its role in nitrogen fixation. This process enables microorganisms to convert atmospheric nitrogen into ammonia, making it biologically available for other organisms. The mechanisms of FeMoco are intricate and not completely understood, but unraveling this could greatly diminish energy usage in fertilizer production and enhance crop yields.
Understanding FeMoco involves determining its lowest energy state, or “ground state” energy, which necessitates examining several electron behaviors. Electrons, being quantum particles, exhibit wave-like properties and occupy distinct regions known as orbits. This complexity has historically made it challenging for classical computers to calculate the various properties of FeMoco accurately.
While approximation methods have shown some success, their energy estimates have been constrained in accuracy. Conversely, rigorous mathematical analyses have demonstrated that quantum computers, utilizing a fundamentally different encoding of complexity, can resolve problems without relying on approximations, exemplifying what is known as ‘quantum advantage.’
Now, researchers such as Garnet Kin Rick Chan from the California Institute of Technology have unveiled a conventional calculation method capable of achieving comparable accuracy to quantum calculations. A pivotal metric in this discussion is “chemical precision,” which signifies the minimum accuracy required to yield reliable predictions in chemical processes. Based on their findings, Chan and colleagues assert that standard supercomputers can compute FeMoco’s ground state energy with the necessary precision.
FeMoco embodies various quantum states, each with distinct energy levels, forming a structure similar to a ladder with the ground state at the base. To streamline the process for classical algorithms to reach this lowest level, researchers concentrated on the states located on adjacent rungs and inferred their implications for what may exist one or two steps below. Insights into the symmetries of the electrons’ quantum states offered valuable context.
This simplification allowed researchers to use classical algorithms to establish an upper limit on FeMoco’s ground state energy and subsequently extrapolate it to a value with an uncertainty consistent with chemical accuracy. Essentially, the computed lowest energy state must be precise enough for future research applications.
Furthermore, researchers estimate that supercomputing methods could outperform quantum techniques, allowing classical calculations that would typically take eight hours to be completed in under a minute. This assumption relies on ideal supercomputer performance.
However, does this discovery mean you’ll instantly understand FeMoco and enhance agricultural practices? Not entirely. Numerous questions remain unanswered, such as which molecular components interact most effectively with nitrogen and what intermediate molecules are produced in the nitrogen fixation process.
“While this study does not extensively detail the FeMoco system’s capabilities, it further elevates the benchmark for quantum methodologies as a model to illustrate quantum benefits,” explains David Reichman from Columbia University in New York.
Dominic Berry, a professor at Macquarie University in Sydney, Australia, highlights that although their team’s research demonstrates that classical computers can approach the FeMoco dilemma, it only does so through approximations, while quantum methods promise complete problem resolution.
“This raises questions about the rationale for utilizing quantum computers for such challenges; however, for more intricate systems, we anticipate that the computational time for classical approaches will escalate much faster than quantum algorithms,” he states.
Another hurdle is that quantum computing technology is still evolving. Existing quantum devices are currently too limited and error-prone for tackling problems like determining FeMoco’s ground state energy. Yet, a new generation of fault-tolerant quantum computers, capable of self-correction, is on the horizon. From a practical standpoint, Berry suggests that quantum computing may still represent the optimal approach to deciphering FeMoco and related molecules. “Quantum computing will eventually facilitate more general solutions to these systems and enable routine computations once fault-tolerant quantum devices become widely available.”
Marco Schioppo and Adam Park monitor ultra-stable lasers at the National Physical Laboratory in Teddington, UK.
David Severn, part of Quantum Untangled (2025), Science Gallery, King’s College London
In a striking portrayal, two physicists observe Britain’s revolutionary quantum technology involving ultra-stable lasers at the National Physical Laboratory in London. Captured by photographer David Severn for the **Quantum Untangled** exhibition at King’s College London, this fascinating image was shortlisted for the **Portrait of Britain Award**.
Severn states, “This portrait offers a rare peek into a domain typically hidden from view, like opening a door to a normally restricted lab.” While the photographs are contemporary, he notes that the scientists’ engagements with technology evoke imagery reminiscent of earlier eras, such as a 1940s submarine pilot or operators of a cotton spinning machine from the turn of the 20th century.
Having no background in quantum mechanics before this venture, Severn was briefed on current quantum physics projects in the UK. He observed that the bewildering aspects of quantum science closely align with artistic perspectives. “Although many scientific concepts eluded my detailed understanding, ideas like superposition and quantum entanglement resonated with me intuitively, akin to artistic realization,” he shared.
3D Printed Helmet Prototype
David Severn, part of Quantum Untangled (2025), Science Gallery, King’s College London
Severn’s captivating photographs highlight a range of innovations in quantum physics, showcasing a **3D-printed helmet** (above) designed to house a quantum sensor that images the brain using magnetic fields. He also features a complex **laser table** (below) monitored by Hartmut Grothe from Cardiff University, ensuring that the vacuum pumps sustaining the system remain operational.
Hartmut Grote at the Laser Table
David Severn, part of Quantum Untangled (2025), Science Gallery, King’s College London
Severn’s photography embraces a mystical quality, showcasing the **3D-printed imaging helmet** used by researchers from the University of Nottingham’s Sir Peter Mansfield Imaging Center (as shown above), along with the intricate network of pumps and mirrors essential for maintaining cleanliness in Grothe’s experiments (as depicted below). Severn asserts that this ethereal essence is intentional.
Joe Gibson Wearing a 3D Printed Imaging Helmet at the University of Nottingham
David Severn, part of Quantum Untangled (2025), Science Gallery, King’s College London
Complex Vacuum System from King’s College London’s Photonics and Nanotechnology Group
David Severn, part of Quantum Untangled (2025), Science Gallery, King’s College London
Severn references a favorite quote from photographer Diane Arbus: “Photographs are secrets about secrets. The more they tell you, the less you understand.” He finds a parallel in quantum physics, where just when one thinks they’ve grasped how light behaves, the quantum realm subverts those expectations and exposes the elusive truths underpinning our understanding of reality.
The **Quantum Untangled** exhibition is on display at the Science Gallery at King’s College London until February 28, 2025. This event is a reimagining of the traveling exhibition **Cosmic Titans: Art, Science and the Quantum Universe** organized by Lakeside Arts and ARTlab at the University of Nottingham.
Innovative quantum computers may enhance our ability to detect exoplanets and analyze their characteristics in unprecedented detail.
Astronomers have identified thousands of planets beyond our solar system, but they believe billions of exoplanets remain to be uncovered. This exploration is crucial for the search for extraterrestrial life, though the distance from Earth complicates direct observations.
Johannes Borregard and his team at Harvard University propose that quantum computing technology could dramatically streamline this endeavor.
Capturing images of exoplanets involves detecting their faint light signals, which diminish as they traverse vast cosmic distances. Additionally, these signals can be obscured by the light of nearby stars, creating additional challenges.
According to Borregard, his NASA colleagues illustrated the difficulty of this task, likening it to locating a single photon amidst a sea of light during telescope observations.
Traditional processing methods struggle with such weak signals. However, quantum computers can harness the quantum states of incoming photons, utilizing their unique properties to gather crucial data about exoplanets. This approach could transform what typically produces indistinct images or singular blurred points into clear visuals of distant worlds, revealing light-based markers of molecules present on these exoplanets.
The central concept of the team’s proposal suggests that light from an exoplanet interacts with a quantum computing device crafted from specially engineered diamond. This technology has already shown success in storing quantum states of photons. These states would then be transmitted to an advanced quantum computer designed to process and generate images of exoplanets. In their model, Borregard and his colleagues envision the second device utilizing ultracold atoms, which have demonstrated significant potential in recent experiments.
Research indicates that employing quantum devices in this manner could produce images using only one-hundredth, or even one-thousandth, of the photons needed in conventional methods. Essentially, in scenarios of extremely weak light, quantum systems could surpass existing technology.
“Since photons adhere to quantum mechanics principles, it is intuitive to explore quantum approaches for detecting and processing light from exoplanets,” notes Cosmolpo from the Polytechnic University of Bari, Italy. However, he acknowledges that realizing this proposal poses significant challenges, necessitating precise control over both quantum computers and effective coordination between them.
Borregard concurs, recognizing promising experimental advancements in employing diamond-based and cryogenic quantum computers. He highlights that establishing a connection between these systems is currently a focus for several research teams, including his own.
Lupo introduces another innovative strategy leveraging quantum light properties. Current initiatives utilizing quantum devices have already begun to observe stars in the Canis Minor constellation. “I am eager to witness the influence of quantum computing on imaging and astronomy in the future,” he states. “This new research represents a pivotal step in that direction.”
Discover Chile: The Global Hub of Astronomy
Immerse yourself in Chile’s astronomical wonders. Experience cutting-edge observatories and gaze at the stars beneath the world’s clearest skies.
Quantum Computers and Heisenberg’s Uncertainty Principle
Marijan Murat/DPA/Alamy
The Heisenberg Uncertainty Principle imposes limits on the precision of measuring specific properties of quantum entities. However, recent research suggests that utilizing quantum neural networks may allow scientists to circumvent this barrier.
For instance, when analyzing a chemically relevant molecule, predicting its properties over time can prove challenging. Researchers must first assess its current characteristics, but measuring quantum properties often leads to interference between measurements, complicating the process. The uncertainty principle asserts that certain quantum attributes cannot be accurately measured at the same time; for example, gaining precise momentum data can distort positional information.
According to Zhou Duanlu from the Chinese Academy of Sciences, recent mathematical insights indicate that quantum neural networks may address these measurement challenges more effectively.
Zhou’s team approached this issue from a practical standpoint. For optimal performance of quantum computers, understanding the properties of qubits—quantum computing’s fundamental components—is crucial. Typical operations, akin to dividing by 2, are employed to yield information about qubits. Yet, the uncertainty principle presents challenges akin to the incompatibility encountered when attempting to execute several conflicting arithmetic operations simultaneously.
Their findings propose that leveraging quantum machine learning algorithms, or Quantum Neural Networks (QNNs), could effectively resolve the compatibility issues inherent to quantum measurements.
Notably, these algorithms rely on randomly selected steps from a predefined set, as shown in previous studies. Zhou et al. demonstrated that introducing randomness into QNNs can enhance the accuracy of measuring a quantum object’s properties. They further extended this approach to simultaneously measure various properties typically constrained by the uncertainty principle, using advanced statistical techniques to aggregate results from multiple random operations for improved precision.
As noted by Robert Fan, this capability to measure multiple incompatible properties swiftly could accelerate scientific understanding of specific quantum systems, significantly impacting quantum computing fields in chemistry and material sciences, as well as large-scale quantum computer research.
The practicality of this innovative approach appears promising, though its effectiveness will hinge on how it compares against other methodologies employing randomness to facilitate reliable quantum measurements, Huang asserts.
El Capitan Supercomputer: Power Play in Quantum Computing
Credit: LLNL/Garry McLeod
The advancement of large quantum computers offers the potential to solve complex problems beyond the reach of today’s most powerful classical supercomputers. However, this leap in capability may come with increased energy demands.
Currently, most existing quantum computers are limited in size, with less than 1,000 qubits. These fragile qubits are susceptible to errors, hindering their ability to tackle significant issues, like aiding in drug discovery. Experts agree that to reach practical utility, a Fault-Tolerant Quantum Computer (FTQC) must emerge, with a much higher qubit count and robust error correction. The engineering hurdles involved in this pursuit are substantial, compounded by multiple competing designs.
Olivier Ezratty, from the Quantum Energy Initiative (QEI), warns that the energy consumption of utility-scale FTQCs has been largely overlooked. During the Q2B Silicon Valley Conference in Santa Clara, California, on December 9, he presented his preliminary estimates. Notably, some FTQC designs could eclipse the energy requirements of the world’s top supercomputers.
For context, El Capitan, the fastest supercomputer globally, located at Lawrence Livermore National Laboratory, draws approximately 20 megawatts of electricity—three times that of the nearby city of Livermore, which has a population of 88,000. Ezratty forecasts that FTQC designs scaling up to 4,000 logical qubits may demand even more energy. Some of the power-hungry designs could require upwards of 200 megawatts.
Ezratty’s estimates derive from accessible data, proprietary insights from quantum tech firms, and theoretical models. He outlines a wide energy consumption range for future FTQCs, from 100 kilowatts to 200 megawatts. Interestingly, he believes that three forthcoming FTQC designs could ultimately operate below 1 megawatt, aligning with conventional supercomputers utilized in research labs. This variance could significantly steer industry trends, particularly as low-power models become more mainstream.
The discrepancies in projected energy use stem from the various strategies that quantum computing companies employ to construct and maintain their qubits. For instance, certain qubit technologies necessitate extensive cooling to function effectively. Light-based qubits struggle with warm light sources and detectors, leading to heightened energy consumption. Similarly, superconducting circuits require entire chips to be housed in large refrigeration systems, while designs based on trapped ions or ultracold atoms demand substantial energy input from lasers or microwaves to precisely control qubits.
Oliver Dial from IBM, known for superconducting quantum computers, anticipates that his company’s large-scale FTQC will need approximately 2 to 3 megawatts of power, a fraction of what a hyperscale AI data center could consume. This demand could be lessened through integration with existing supercomputers. Meanwhile, a team from QuEra, specializing in ultracold atomic quantum computing, estimates their FTQC will require around 100 kilowatts, landing on the lower end of Ezratty’s spectrum.
Other companies like Xanadu, focusing on light-based quantum technologies, as well as Google Quantum AI, centered on superconducting qubits, have opted not to comment. PsiQuantum, another light-based qubit developer, was unavailable for a response. New Scientist has made multiple attempts for their insights.
Ezratty also pointed out that traditional electronics responsible for directing and monitoring qubit operations could result in additional costs, particularly for FTQC systems where qubits need further instructions to self-correct errors. This complexity necessitates understanding how these algorithms contribute to energy footprints. The operational runtime length of quantum computers adds another layer, as energy savings from fewer qubits might be negated if longer operation times are needed.
To effectively measure and report the energy consumption of machines, the industry must establish robust standards and benchmarks. Ezratty emphasizes that this is an integral element of QEI’s mission, with projects actively progressing in both the United States and the European Union.
As the field of quantum computing continues to mature, Ezratty anticipates that his research will pave the way for insights into FTQC energy consumption. This understanding could be vital for optimizing designs to minimize energy use. “Countless technological options could facilitate reduced energy consumption,” he asserts.
Researchers from the University of Waterloo and Kyushu University have achieved a groundbreaking advancement in quantum computing by developing a novel method to create redundant, encrypted copies of qubits. This represents a pivotal step towards practical quantum cloud services and robust quantum infrastructure.
Google’s quantum computer – Image credit: Google.
In quantum mechanics, the no-cloning theorem asserts that creating an identical copy of an unknown quantum state is impossible.
Dr. Achim Kempf from the University of Waterloo and Dr. Koji Yamaguchi from Kyushu University emphasize that this fundamental rule remains intact.
However, they have demonstrated a method to generate multiple encrypted versions of a single qubit.
“This significant breakthrough facilitates quantum cloud storage solutions, such as quantum Dropbox, quantum Google Drive, and quantum STACKIT, enabling the secure storage of identical quantum information across multiple servers as redundant encrypted backups,” said Dr. Kemp.
“This development is a crucial step towards establishing a comprehensive quantum computing infrastructure.”
“Quantum computing offers immense potential, particularly for addressing complex problems, but it also introduces unique challenges.”
“One major difficulty in quantum computing is the no-duplication theorem, which dictates that quantum information cannot be directly copied.”
“This limitation arises from the delicate nature of quantum information storage.”
According to the researchers, quantum information functions analogously to splitting passwords.
“If you possess half of a password while your partner holds the other half, neither can be utilized independently. However, when both sections are combined, a valuable password emerges,” Dr. Kemp remarked.
“In a similar manner, qubits are unique in that they can share information in exponentially growing ways as they interconnect.”
“A single qubit’s information is minimal; however, linking multiple qubits allows them to collectively store substantial amounts of information that only materializes when interconnected.”
“This exceptional capability of sharing information across numerous qubits is known as quantum entanglement.”
“With 100 qubits, information can be simultaneously shared in 2^100 different ways, allowing for a level of shared entangled information far exceeding that of current classical computers.”
“Despite the vast potential of quantum computing, the no-cloning theorem restricts its applications.”
“Unlike classical computing, where duplicating information for sharing and backup is a common practice, quantum computing lacks a simple ‘copy and paste’ mechanism.”
“We have uncovered a workaround for the non-replicability theorem of quantum information,” explained Dr. Yamaguchi.
“Our findings reveal that by encrypting quantum information during duplication, we can create as many copies as desired.”
“This method circumvents the no-clonability theorem because when an encrypted copy is selected and decrypted, the decryption key is automatically rendered unusable; it functions as a one-time key.”
“Nevertheless, even one-time keys facilitate crucial applications such as redundant and encrypted quantum cloud services.”
Discover more insights in the Lost in Space-Time newsletter. Register for the latest updates from the universe.
Introduction
Since the 5th century AD, the phrase “In the beginning” has sparked intrigue, originating from the writings of an Israeli priest known as “P.” This profound beginning resonates with our modern understanding of the cosmos. Here’s a glimpse into the universe’s birth:
Words falter when describing the universe’s origins, transcending mere physics and human experience. By retracing our steps, we assert that the universe emerged from a hot Big Bang approximately 13.8 billion years ago. The early universe, characterized by rapid expansion, underwent quantum fluctuations, which left enduring marks.
These fluctuations allowed some regions to expand more rapidly, forming hyperdensities of hot matter, while others lagged, resulting in varying densities. About 100 seconds post-Big Bang, baryonic matter took shape: hydrogen nuclei, helium nuclei, and free electrons. Alongside, dark matter emerged as its elusive counterpart.
Initially, the universe existed as a hot plasma—fluidic and dominated by intense radiation—expanding with Big Bang momentum, aided by dark energy. As expansion slowed over 9 billion years, dark energy escalated the expansion rate.
This early universe’s excess density was predominantly dark matter, with small baryonic matter contributions. Gravity pulled these together, while radiation acted as a binding force. The pressure from this radiation created acoustic vibrations or sound waves within the plasma.
Although these waves were not audible, they traveled faster than half the speed of light, with wavelengths spanning millions of light-years. This era signifies the genesis of our universe.
As the pressure waves from radiation expanded outward, they dragged negatively charged electrons and their heavier baryon counterparts. Dark matter, indifferent to radiation interactions, remained behind, resulting in a spherical wave of dense baryonic material expanding outward.
The propagation speed of these sound waves reflected the baryonic material and radiation’s density. Early waves had smaller amplitudes and higher frequencies, readily damped after minimal cycles, akin to ultrahigh-frequency sound waves.
As the universe continued its expansion and cooldown, roughly 380,000 years later, electrons merged with hydrogen and helium nuclei, giving rise to neutral atoms in a process known as recombination. This event, spanning about 100,000 years, produced cosmic background radiation—an elusive imprint awaiting discovery.
Map of Cosmic Microwave Background Radiation Exhibiting Density Fluctuations
Collaboration between ESA and Planck
The radiation pressure and sound speed decreased significantly, creating a frozen spherical shell of baryonic material, similar to debris washed ashore by a storm. The largest compressional wave left behind a concentrated sphere of visible matter, termed the sonic horizon, roughly 480 million light-years from the original overdensity.
Early compressional waves left minor imprints on the universe’s matter distribution, while later waves, generated right before recombination, exhibited greater amplitude and lower frequency, observable in today’s cosmic background radiation.
Consequently, regions of high density yield slightly warmer background radiation, while lower density areas produce cooler radiation. This frozen state incorporates traces of matter distribution just after the Big Bang, known as a “feature of the universe.”
The wavelength of these final sound waves closely relates to the curvature of space, while the Hubble constant integrates our understanding of the cosmos measured over 13 billion years.
Both quantum fluctuations and acoustic vibrations provide distinct signatures, akin to cosmic fingerprints. The first evidence emerged on April 23, 1992, revealing temperature variations in a cosmic background radiation map produced by the COBE satellite. George Smoot, the lead researcher, highlighted its monumental significance, describing it as a divine encounter for believers.
Observing distinct directions in the cosmos creates a triangle projecting into space, with the vertex angle referred to as the angular scale. A favorable horizon results in a higher probability of encountering a hot spot within the cosmic background approximately 480 million light-years from another hot spot, corresponding to an angular scale of around 1°.
This measurement surpasses the resolution of earlier instruments, with the WMAP and Planck satellite missions unveiling additional acoustic vibrations down to angular scales under 0.1°.
The origins of baryonic matter contributed to cosmic structures, with small overdensities serving as seeds for star and galaxy formation, while underdensities created voids within the universe’s large-scale structure, known as the cosmic web. Thus, the probability of finding galaxy chains roughly 480 million light-years from each other slightly increases.
By analyzing acoustic vibrations, astrophysicists have accurately assessed cosmological parameters, including baryonic matter density, dark matter, dark energy, and the Hubble constant among others. However, contentment is elusive, as the standard cosmological inflation model (Lambda CDM) reveals we only observe 4.9% of the universe, with dark matter comprising 26.1% and dark energy making up 69%.
The enigma remains: we have yet to uncover the true nature of dark matter and dark energy.
Jim Baggott’s upcoming book, Disharmony: A History of the Hubble Constant Problem, is scheduled for release in the US by Oxford University Press in January 2026.
What sets quantum computers apart from classical machines? Recent experiments suggest that “quantum contextuality” may be a critical factor.
Quantum computers fundamentally differ from traditional systems by leveraging unique quantum phenomena absent in classical electronics. Their building blocks, known as qubits, can exist in a superposition state, representing two properties simultaneously, which are typically incompatible, or they can be interconnected through a phenomenon called quantum entanglement.
Researchers at Google Quantum AI have conducted several groundbreaking demonstrations using the Willow quantum computer, revealing that quantum contextuality is also significant.
Quantum contextuality highlights an unusual aspect of measuring quantum properties. Unlike classical objects, where attributes are stable regardless of measurement order, quantum measurements are interdependent.
This phenomenon has previously been explored in special experiments with quantum light, and in 2018, researchers mathematically proved its potential application in quantum computing algorithms.
This algorithm enables quantum computers to uncover hidden patterns within larger mathematical structures in a consistent number of operations, regardless of size. In essence, quantum contextuality makes it feasible to locate a needle in a haystack, irrespective of the haystack’s dimensions.
In our experiments, we scaled qubit numbers from a few to 105, analogous to increasing the haystack size. While the number of steps rose with additional qubits, Willow demonstrated superior noise and error management compared to an ideal theoretical quantum computer for the algorithm involved. Notably, it still required fewer steps than traditional computers would need.
Thus, quantum contextuality appears to confer a quantum advantage, allowing these computers to utilize their unique characteristics to outperform classical devices. The research team also executed various quantum protocols reliant on contextuality, yielding stronger effects than previous findings.
“Initially, I couldn’t believe it. It’s genuinely astonishing,” says Adan Cabello from the University of Seville, Spain.
“These findings definitively showcase how modern quantum computers are redefining the limits of experimental quantum physics,” states Vir Burkandani at Rice University, Texas, suggesting that a quantum computer, as a candidate for practical advantages, should accomplish these tasks to confirm its quantum capabilities.
However, this demonstration does not yet confirm the superiority of quantum technology for practical applications. The 2018 research established that quantum computers are more effective than classical ones only when using more qubits than those in Willow, as well as employing qubits with lower error rates, asserts Daniel Lidar at the University of Southern California. The next crucial step may involve integrating this new study with quantum error correction algorithms.
This experiment signifies a new benchmark for quantum computers and underscores the importance of fundamental quantum physics principles. Cabello emphasizes that researchers still lack a complete theory explaining the origins of quantum superiority, but unlike entanglement—which often requires creation—contextuality is inherently present in quantum objects. Quantum systems like Willow are now advanced enough to compel us to seriously consider the peculiarities of quantum physics.
Quantum Computers: Solutions for Chemistry Challenges
Marijan Murat/DPA/Alamy
One of the critical questions in the quantum computing sector is whether these advanced machines can solve practical problems in fields like chemistry. Researchers in industrial and medical chemistry are poised to provide insights by 2026.
The complexity of determining the structure, reactivity, and other properties of molecules is inherently a quantum problem, primarily involving electrons. As molecular structures grow increasingly complex, these calculations become challenging, sometimes even surpassing the capabilities of traditional supercomputers.
Quantum computers, being inherently quantum, have a potential advantage in tackling these complex chemical calculations. As these computers develop and become more seamlessly integrated with conventional systems, they are gaining traction in the chemistry sector.
For instance, in 2025, IBM and the Japanese Institute of Scientific Research collaborated, employing quantum computers alongside supercomputers to model various molecules. Google researchers have also been innovating algorithms that unveil molecular structures. Additionally, RIKEN researchers are teaming up with Quantinuum to create efficient workflows, allowing quantum computers to calculate molecular energy with remarkable precision. Notably, the quantum computing software platform Kunova Computing introduced an algorithm that reportedly operates ten times more efficiently than traditional methods for energy calculations.
Progress is expected to expedite by 2026 as quantum computers become more advanced. “Future larger machines will allow us to create enhanced workflows, ultimately solving prevalent quantum chemistry problems,” states David Muñoz Ramo from Quantinuum. While his team currently focuses on hydrogen molecules, they foresee stepping into more intricate structures, such as catalysts for industrial reactions.
Other research entities are making strides in similar areas. In December, Microsoft announced a partnership with Algorithmiq, a quantum software startup, aimed at accelerating the development of quantum algorithms for chemistry. Furthermore, a study by Hyperion Research highlights chemistry as a focal area for advancement and investment in quantum computing, ranking it as one of the most promising applications in annual surveys.
However, meaningful progress in quantum chemical calculations depends on achieving error-free or fault-tolerant quantum computers, which will also unlock other potential applications for these devices. As Philip Schleich and Alan Aspuru-Guzik emphasized in a commentary for Science magazine, the ability of quantum computers to outperform classical computers hinges on the development of fault-tolerant algorithms. Thankfully, achieving fault tolerance is a widely accepted goal among quantum computer manufacturers worldwide.
In February, Microsoft unveiled the Majorana 1 quantum computer, igniting debates in the quantum computing community.
The Majorana 1 is noteworthy for its use of topological qubits, which promise enhanced error resistance compared to traditional qubit designs. Microsoft has pursued the development of topological qubits grounded in the elusive Majorana zero mode (MZM), facing mixed results throughout its journey.
In 2021, a significant paper from Microsoft researchers was retracted by Nature due to identified analytical flaws in their research on topological qubits. Furthermore, evaluations of experiments leading up to Majorana 1 received heavy criticism in 2023.
Consequently, the 2025 paper from Nature announcing Majorana 1 faced heightened scrutiny. Notably, the editorial team claimed, “The results in this manuscript do not represent evidence of the presence of Majorana zero mode in the reported devices.” In contrast, Microsoft’s press release asserted the opposite.
Chetan Nayak from Microsoft addressed concerns during a packed presentation at the American Physical Society Global Summit in Anaheim, California, in March. Despite presenting new data, skepticism remained prevalent among critics.
“The data presented does not demonstrate a functional topological qubit, let alone the basic components of one,” stated Henry Legg, a professor at the University of St Andrews, expressing his reservations.
In response, Nayak contended that the community’s feedback has been enthusiastic and engaged. “We’re observing thoughtful discussions and intriguing responses regarding our recent findings and ongoing efforts,” he noted.
In July, additional data emerged, with researchers like Kim Eun-ha from Cornell University asserting that these results exhibit characteristics more indicative of a topological qubit than previously shown. “It’s encouraging to witness the progress,” she emphasized.
Nayak and his team remain optimistic about future advancements, aiming to escalate their quantum computing capabilities beyond Majorana 1. This initiative was selected for the final phase of the Quantum Benchmarking Initiative led by the U.S. Defense Advanced Research Projects Agency, focusing on practical approaches toward building viable quantum computers.
“This past year has been transformative for our quantum program, and the introduction of the Majorana 1 chip marks a crucial milestone for both Microsoft and the quantum computing sector,” stated Nayak.
Looking ahead to 2026, will Microsoft’s endeavors finally quell the critics? Legg remains doubtful: “Fundamental physics doesn’t adhere to schedules dictated by major tech corporations,” he remarked.
The quantum computing industry is concluding the year with renewed hope, despite the absence of fully operational quantum systems. At December’s Q2B Silicon Valley Conference, industry leaders and scientists expressed optimism regarding the future of quantum computing.
“We believe that it’s highly likely that someone, or perhaps several entities, will develop a genuinely industrially viable quantum computer, but we didn’t anticipate this outcome until the end of 2025,” stated Joe Altepeter, program manager for the Defense Advanced Research Projects Agency’s Quantum Benchmarking Initiative (QBI). The QBI aims to evaluate which of the competing quantum computing approaches can yield practical devices capable of self-correction or fault tolerance.
This initiative will extend over several years, involving hundreds of professional evaluators. Reflecting on the program’s initial six months, Altepeter noted that while “major roadblocks” were identified in each approach, none disqualified any team from the pursuit of practical quantum devices.
“By late 2025, I sense we will have all major hardware components in place with adequate fidelity; the remaining challenges will be primarily engineering-focused,” asserted Scott Aaronson, a key figure in the field, during his presentation at the University of Texas at Austin. He acknowledged the ongoing challenge of discovering algorithms for practical quantum applications, but highlighted significant progress in hardware developments.
Though quantum computing hardware advancements are encouraging, application development is lagging, according to Ryan Babush from Google. During the conference, Google Quantum AI alongside partners unveiled the finalists for the XPRIZE competition, aiming to accelerate application development.
The research by the seven finalists spans simulations of biomolecules crucial for human health, algorithms enhancing classical simulations for clean energy materials, and calculations that could impact the diagnosis and treatment of complex health issues.
“A few years back, I was skeptical about running applications on quantum computers, but now my interest has significantly increased,” remarked John Preskill, a pivotal voice in quantum computing at Caltech, advocating for the near-term application of quantum systems in scientific discovery.
Over the past year, numerous quantum computers have been employed for calculations, including the physics of materials and high-energy particles, potentially rivaling or surpassing traditional computational methods.
While certain applications are deemed particularly suitable for quantum systems, challenges remain. For instance, Pranav Gokhale at Inflection, a company manufacturing quantum devices from cryogenic atoms, is implementing Scholl’s algorithm—a classic method capable of breaking many encryption systems used by banks today. However, this initial implementation still lacks the computational power necessary to effectively decrypt real-world encrypted information, illustrating that significant enhancements in both hardware and software are essential.
Dutch startup Quantware has proposed a solution to the industry’s major hardware challenge, asserting that increasing quantum computer size can enhance computational capacity while maintaining reliability. Their quantum processor unit design aims to utilize 10,000 qubits, roughly 100 times the capacity of most current superconducting quantum computers. According to Matt Reilersdam, QuantWare anticipates having its first device operational within two and a half years. Other firms, such as IBM and Quantinuum, are working toward similar large-scale quantum systems, while QuEra aims to fabricate 10,000 qubits from ultra-cold atoms within a year, intensifying the competitive landscape.
Moreover, the quantum computing industry is projected to expand significantly, with global investments expected to rise from $1.07 billion in 2024 to approximately $2.2 billion by 2027, as noted in a Quantum Computing Industry Survey by Hyperion Research.
“More individuals than ever can now access quantum computers, and I believe they will accomplish things we can scarcely imagine,” said Jamie Garcia from IBM.
Quantum Computers Could Shed Light on Quantum Behavior
Galina Nelyubova/Unsplash
Over the past year, I consistently shared the same narrative with my editor: Quantum computers are increasingly pivotal for scientific breakthroughs.
This was the primary intent from the start. The ambition to leverage quantum computers for deeper insights into our universe has been part of its conception, even referenced in Richard Feynman’s 1981 address. In his discussion about effectively simulating nature, he suggested: “Let’s construct the computer itself using quantum mechanical components that adhere to quantum laws.”
Currently, this vision is being brought to life by Google, IBM, and a multitude of academic teams. Their devices are now employed to simulate reality on a quantum scale. Below are some key highlights.
This year’s advancements in quantum technology began for me with two studies in high-energy particle physics that crossed my desk in June. Separate research teams utilized two unique quantum computers to mimic the behavior of particle pairs within quantum fields. One utilized Google’s Sycamore chip, crafted from tiny superconducting circuits, while the other, developed by QuEra, employed a chip based on cryogenic atoms regulated by lasers and electromagnetic forces.
Quantum fields encapsulate how forces like electromagnetism influence particles across the universe. Additionally, there’s a local structure that defines the behaviors observable when zooming in on a particle. Simulating these fields, especially regarding particle dynamics—where particles exhibit time-dependent behavior—poses challenges akin to producing a motion picture of such interactions. These two quantum computers addressed this issue for simplified versions of quantum fields found in the Standard Model of particle physics.
Jad Halime, a researcher at the University of Munich who was not a part of either study, remarked that enhanced versions of these experiments—simulating intricate fields using larger quantum computers—could ultimately clarify particle behaviors within colliders.
In September, teams from Harvard University and the Technical University of Munich applied quantum computers to simulate two theoretical exotic states of matter that had previously eluded traditional experiments. Quantum computers adeptly predicted the properties of these unusual materials, a feat impossible by solely growing and analyzing lab crystals.
Google’s new superconducting quantum computer, “Willow,” is set to be utilized in October. Researchers from the company and their partners leveraged Willow to execute algorithms aimed at interpreting data obtained from nuclear magnetic resonance (NMR) spectroscopy, frequently applied in molecular biochemical studies.
While the team’s demonstration using actual NMR data did not achieve results beyond what conventional computers can handle, the mathematics underlying the algorithm holds the promise of one day exceeding classical machines’ capabilities, providing unprecedented insights into molecular structures. The speed of this development hinges on advancements in quantum hardware technology.
Later, a third category of quantum computer made headlines. Quantinuum’s Helios-1, designed with trapped ions, successfully executed simulations of mathematical models relating to perfect electrical conductivity, or superconductivity. Superconductors facilitate electricity transfer without loss, promising highly efficient electronics and potentially enhancing sustainable energy grids. However, currently known superconductors operate solely under extreme conditions, rendering them impractical. Mathematical models elucidating the reasons behind certain materials’ superconducting properties are crucial for developing functional superconductors.
What did Helios-1 successfully simulate? Henrik Dreyer from Quantinuum provided insights, stating that it is likely the most pivotal model in this domain, capturing physicists’ interests since the 1960s. Although this simulation didn’t unveil new insights into superconductivity, it established quantum computers as essential players in physicists’ ongoing quest for understanding.
A week later, I was on another call with Sabrina Maniscalco discussing metamaterials with the quantum algorithm firm Algorithmiq. These materials can be finely tuned to possess unique attributes absent in naturally occurring substances. They hold potential for various applications, ranging from basic invisibility cloaks to catalysts accelerating chemical reactions.
Maniscalco’s team worked on metamaterials, a topic I delved into during my graduate studies. Their simulation utilized an IBM quantum computer built with superconducting circuits, enabling the tracking of how metamaterials manipulate information—even under conditions that challenge classical computing capabilities. Although this may seem abstract, Maniscalco mentioned that it could propel advancements in chemical catalysts, solid-state batteries, and devices converting light to electricity.
As if particle physics, new states of matter, molecular analysis, superconductors, and metamaterials weren’t enough, a recent tip led me to a study from the University of Maryland and the University of Waterloo in Canada. They utilized a trapped ion quantum computer to explore how particles bound by strong nuclear forces behave under varying temperatures and densities. Some of these behaviors are believed to occur within neutron stars—poorly understood cosmic entities—and are thought to have characterized the early universe.
While the researchers’ quantum computations involved approximations that diverged from the most sophisticated models of strong forces, the study offers evidence of yet another domain where quantum computers are emerging as powerful discovery tools.
Nevertheless, this wealth of examples comes with important caveats. Most mathematical models simulated on quantum systems require simplifications compared to the most complex models; many quantum computers are still prone to errors, necessitating post-processing of computational outputs to mitigate those inaccuracies; and benchmarking quantum results against top-performing classical computers remains an intricate challenge.
In simpler terms, conventional computing and simulation techniques continue to advance rapidly, with classical and quantum computing researchers engaging in a dynamic exchange where yesterday’s cutting-edge calculations may soon become routine. Last month, IBM joined forces with several other companies to launch a publicly accessible quantum advantage tracker. This initiative ultimately aims to provide a leaderboard showcasing where quantum computers excel or lag in comparison to classical ones.
Even if quantum systems don’t ascend to the forefront of that list anytime soon, the revelations from this past year have transformed my prior knowledge into palpable excitement and eagerness for the future. These experiments have effectively transitioned quantum computers from mere subjects of scientific exploration to invaluable instruments for scientific inquiry, fulfilling tasks previously deemed impossible just a few years prior.
At the start of this year, I anticipated primarily focusing on benchmark experiments. In benchmark experiments, quantum computers execute protocols showcasing their unique properties rather than solving practical problems. Such endeavors can illuminate the distinctions between quantum and classical computers while underscoring their revolutionary potential. However, transitioning from this stage to producing computations useful for active physicists appeared lengthy and undefined. Now, I sense this path may be shorter than previously envisioned, albeit with reasonable caution. I remain optimistic about uncovering more quantum surprises in 2026.
Quantum particles now have an extended capacity to carry useful information.
koto_feja/Getty Images
The intriguing phenomenon of quantum superposition has enabled scientists to surpass the limitations imposed by fundamental quantum mechanics, equipping quantum objects with properties advantageous for long-term quantum computing.
For over a century, physicists have wrestled with the challenge of distinguishing between the minuscule quantum world and the larger macroscopic universe. In 1985, physicists Anthony Leggett and Anupam Garg introduced a mathematical assessment for determining the size threshold at which an object transcends its quantum characteristics. Quantum objects are recognized by remarkably strong correlations of their properties over time, akin to surprising connections between actions of yesterday and tomorrow.
Objects that achieve a sufficient score in this assessment are classified as quantum, with the scores traditionally held back by a value known as the temporal Zirelson limit (TTB). Theorists believed that even distinctly quantum objects could not surpass this threshold. However, Arijit Chatterjee and his colleagues from the Indian Institute of Science Education and Research in Pune have discovered a method to significantly exceed the TTB using one of the most basic quantum elements.
They centered their research on qubits, the essential building blocks of quantum computers and other quantum information systems. While qubits can be produced through various methods, the team utilized a carbon-based molecule incorporating three qubits. The first qubit was employed to control the behavior of the second “target” qubit over time, with the third qubit employed to extract properties from the target.
Though three-qubit configurations are generally believed to be constrained by the TTB, Chatterjee and his team discovered a method to push the target qubits beyond this limitation dramatically. In fact, their technique resulted in one of the most significant deviations from mathematical plausibility. The key was for the first qubit to govern the target qubit while it was in a state of quantum superposition, where it can effectively embody two states or actions that seem mutually exclusive. For instance, in their experiment, the first qubit directed the target qubit to rotate both clockwise and counterclockwise simultaneously.
Qubits are usually susceptible to decoherence over time, diminishing their capacity to store quantum information. However, after the target qubit surpassed the TTB, decoherence set in, yet the ability to encode information persisted five times longer due to its time-controlled behavior influenced by superposition.
According to Chatterjee, this resilience is advantageous in any context requiring precise qubit control, such as in computational applications. Team member HS Kartik from Poland’s University of Gdańsk mentions that procedures in quantum metrology, including accurate sensing of electromagnetic fields, could benefit significantly from this level of qubit control.
Rakura and their colleagues from China’s Sun Yat-sen University indicate that this research not only has clear potential for enhancing quantum computing practices but also fundamentally broadens our comprehension of how quantum objects behave over time. This is significant because immensely surpassing the TTB indicates that the properties of the qubit are highly interconnected at two divergent time points, a phenomenon absent in non-quantum entities.
The substantial breach of the TTB strongly demonstrates the extent of quantum characteristics present throughout the three-qubit configuration and exemplifies how researchers are advancing the frontiers of the quantum domain, says Karthik.
Double-slit experiment showcases the quantum nature of reality
Russell Kightley/Science Photo Library
A thought experiment that sparked a famous debate between physicists Albert Einstein and Niels Bohr in 1927 has now been realized. This breakthrough addresses one of quantum physics’ fundamental mysteries: is light truly a wave, a particle, or an intricate mix of both?
The debate centers on the double-slit experiment, tracing back another century to 1801, when Thomas Young used it to argue for the wave nature of light, while Einstein contended it is a particle. Bohr’s contributions to quantum physics suggested that both perspectives could hold true. Einstein, critical of this notion, designed a modified version of Young’s experiment to counter it.
<p>Recently, <a href="https://quantum.ustc.edu.cn/web/en/node/137">Chaoyan Lu</a> and his team at the University of Science and Technology of China utilized cutting-edge technology in experimental physics to verify Einstein's theories, demonstrating the unique dual wave-particle character of quantum objects, as theorized in the 1920s. "Witnessing quantum mechanics 'in action' at such a foundational level is awe-inspiring," remarks Lu.</p>
<p>In the classic double-slit experiment, light is directed at two narrow parallel slits in front of a screen. If light were entirely particles, the screen would display a distinct light blob behind each slit. However, researchers observed an "interference pattern" of alternating dark and bright bands instead. This demonstrates that light behaves like waves passing through a slit, creating ripples that collide on the screen. Notably, this interference pattern remains evident even when the light intensity is reduced to a single photon. Does this imply that photons, which exhibit particle-like behavior, also interfere like waves?</p>
<p>Bohr proposed the idea of "complementarity," stating that one cannot simultaneously observe the particle nature of a photon showing wave-like behavior, and vice versa. Amid discussions on this matter, Einstein envisioned an additional spring-loaded slit that would compress when a photon entered. By analyzing the movement of the spring, physicists could determine which slit a photon passed through. Einstein believed this approach allowed for a simultaneous description of both particle and wave behavior, creating an interference pattern that contradicts complementarity.</p>
<section></section>
<p>Lu's team aimed to create a setup at the "ultimate quantum limit," firing a single photon rather than using a slit, but rather an atom that could recoil similarly. Upon impacting the atom, the photon entered a quantum state that allowed it to propagate left and right, which also produced an interference pattern upon reaching the detector. To achieve this, researchers utilized lasers and electromagnetic forces to significantly cool the atoms, enabling precise control over their quantum properties. This was vital for testing Bohr's claims against Einstein's. Bohr argued that Heisenberg's uncertainty principle could disrupt the interference pattern when momentum fluctuations of the slit due to recoil are well known, rendering the photon’s position highly ambiguous, and vice versa.</p>
<p>"Bohr's response was brilliant, but such thought experiments remained theoretical for almost a century," notes Lu.</p>
<p>By adjusting the laser, Lu's team could control the momentum uncertainty of the atoms as they slitted. They found that Bohr was indeed correct; finely tuning these momentum ambiguities could eliminate interference patterns. Remarkably, the team could access intermediate regions to measure recoil information, observing blurred versions of interference patterns. Essentially, the photon displayed both wave and particle characteristics simultaneously, according to Lu.</p>
<p>``The real intrigue lies in [this] intermediate realm," states <a href="https://physics.mit.edu/faculty/wolfgang-ketterle/">Wolfgang Ketterle</a> from the Massachusetts Institute of Technology. Early this year, he and his team conducted a variation of Einstein's experiment, using ultracold atoms controlled by lasers that could pass through two slits. Lu's group utilized a single atom to scatter light in two directions; both atoms scattered light in the same direction, and changes in its quantum state indicated the influence of the photons colliding with each atom. Ketterle emphasizes that this approach provides a distinct means to explore wave-particle duality, offering clearer insights into photon behavior since this "which direction" information is recorded in one of the two separate atoms, albeit deviating slightly from Einstein's premise.</p>
<p>Furthermore, he and his colleagues performed experiments where they abruptly switched off the laser (similar to removing a spring from a moving slit) and subsequently directed photons at the atoms. Bohr's conclusions held, as the uncertainty principle impacted the momentum exchange between atoms and photons, potentially "washing out" the interference fringes. This spring-free iteration of Einstein's concept had remained untested until now, according to Ketterle. "Nuclear physics presents an excellent opportunity to apply cold atoms and lasers for a clearer illustration of quantum mechanics, a possibility not achievable before."</p>
<p><a href="https://physik.unibas.ch/en/persons/philipp-treutlein/">Philip Treutlein</a> and his colleagues at the University of Basel in Switzerland assert that both experiments strongly reinforce fundamental aspects of quantum mechanics. "From our modern perspective, we understand how quantum mechanics operates on a microscopic level. Yet witnessing the empirical realization of these principles is always impactful." The experiments led by Lu align conceptually with historical records of the debates between Bohr and Einstein, affirming that quantum mechanics behaves as predicted.</p>
<p>For Lu, there remains more work on categorizing the quantum state of the slit and increasing its mass. However, the experiment carries significant educational importance. "Above all, I hope to illustrate the sheer beauty of quantum mechanics," he shares. "If more young individuals witness the real-time emergence and disappearance of interference patterns and think, 'Wow, this is how nature functions,' then the experiment will already be a success."</p>
<section class="ArticleTopics" data-component-name="article-topics">
<p class="ArticleTopics__Heading">topic:</p>
</section>
Adolf Hitler’s death is recorded as April 30, 1945. At least, that’s the official narrative. However, some historians contest this, suggesting he escaped war-torn Berlin and lived in secrecy. Today, this alternate theory is largely viewed as a conspiracy, yet no rational historian can deny that, regardless of the available evidence, the “facts in question” existed. Hitler was either deceased that day or he was not. It’s nonsensical to suggest that he was both alive and dead on May 2, 1945. But if we replace Adolf Hitler with Schrödinger’s renowned cat, the historical “facts” become quite muddled.
Schrödinger is recognized as a foundational figure in quantum mechanics, the most successful scientific framework to date. It serves as the backbone for many fields, including chemistry, particle physics, materials science, molecular biology, and astronomy, yielding remarkable technological advancements, from lasers to smartphones. Yet, despite its successes, the essence of quantum mechanics appears perplexing at its core.
In our daily lives, we operate under the assumption that an “external” real world exists where objects like tables and chairs possess clearly defined traits, such as position and orientation, independent of observation. In the macroscopic realm, our observations merely uncover a pre-existing reality. Conversely, quantum mechanics governs the microscopic domain of atoms and subatomic particles, where certainty and clarity dissolve into ambiguity.
Quantum uncertainty implies that the future is not entirely dictated by the present. For example, if an electron is directed toward a thin barrier with a known speed, it can either bounce back or tunnel through, emerging on the opposite side. Similarly, if an atom becomes excited, it might remain excited or decay and emit a photon a few microseconds later. In both scenarios, predicting outcomes with certainty is impossible—only probabilistic estimates can be offered.
Most individuals are comfortable with the idea that the future holds uncertainties. However, quantum indeterminacy similarly applies to the past. The process is not yet complete. When scrutinized at a minute scale, history transmutes into a blend of alternate possibilities, a state known as superposition.
The hazy picture of the quantum microcosm sharpens during measurements. For instance, localizing an electron may show it at a specific location; however, quantum mechanics asserts that this doesn’t imply the electron previously existed in that state. It is already there. Observations merely disclose the specific location prior to measurement. Rather, measurement transforms the electron from a state without a defined location into one with a defined position.
So, how should we conceptualize electrons prior to observation? Picture an abundance of semi-real “ghost electrons” dispersed in space, each denoting a distinct potential. The reality dwells in an indeterminate state. This notion is sometimes explained by stating that an electron occupies multiple locations simultaneously. Moreover, measurements serve to convert a certain “ghost” into tangible reality while eliminating its counterparts.
Does the experimenter have control over the outcome? Not if they opt for the prevailing ghost. The process hinges on randomness. Yet, a layer of choice is present, which is vital for grasping quantum reality. If, instead of measuring position, the experimenter decides to assess the electron’s speed, the fuzzy initial state resolves into a distinct result. This time, instead of locating electrons, measurements yield electrons with velocity. Interestingly, it appears that electrons with speed exhibit wave-like properties, distinct from their particle nature. Thus, electrons embody both wave and particle characteristics, contingent on the measurement approach.
In summary: the behavior of electrons—as waves or particles—is dictated by the type of measurement the experimenter chooses. While this may seem bizarre, the situation grows even stranger. What has transpired to atoms before measurement relies on the experimenter’s selections. In essence, the properties of electrons—wave or particle—are contingent upon one’s choices, suggesting that something may have retroactively influenced the “external” world prior to measurement.
Is this time travel? Retroactive causality? Telepathy? These terms are often overused in popular quantum physics discussions, but the clearest explanation comes from John Wheeler, who coined the term black hole: “The past exists solely as recorded in the present,” he asserted.
While Mr. Wheeler’s assertion is thought-provoking, is there an actual experiment that validates it? Over breakfast at the Hilton Hotel in Baltimore in 1980, Wheeler mentioned a curious inquiry: “How do you suppress the ghosts of photons?” Recognizing my bewilderment, he proceeded to elaborate on a unique twist he devised for a classical quantum experiment, applicable to light, electrons, or even entire atoms.
This experiment traces back to the British polymath Thomas Young, who in 1801 aimed to demonstrate the wave properties of light. Young established a screen with two closely placed slits and illuminated it with a pinprick of light. What transpired? Instead of the anticipated two blurred light bands, Young observed a series of bright and dark stripes known as interference fringes. This phenomenon arises because light waves passing through each slit disperse, where they amplify and create brighter sections through constructive interference while canceling out in others, resulting in dark patches through destructive interference.
Light passing through two slits in a screen during a double-slit experiment
Russell Kightley/Science Photo Library
The conversation surrounding quantum mechanics began with scientists debating whether light consists of waves or particles called photons. The resolution is that it is both. Thanks to modern advancements, we can conduct Young’s experiment one photon at a time. Each photon produces a minuscule dot on the second screen, and over time, multiple dots accumulate, forming the characteristic striped pattern unearthed by Young. This situation raises questions: if a photon is a minuscule particle, it should clearly pass through either slit or the other. Yet, both slits are necessary to create the interference pattern.
What occurs if an astute experimenter wants to determine the slit a particular photon travels through? A detector can be placed near a slit to achieve this. Once that occurs, the interference pattern vanishes. The act of detecting effectively causes the photons to assume a particle-like behavior, obscuring their wave characteristics. The same principle applies to electrons; one can either pinpoint which slit the electrons traverse, resulting in the absence of interference stripes, or obscure their pathways and observe stripes manifest after numerous electrons have produced the pattern. Thus, experimenters can dictate whether photons, or electrons for that matter, act like waves or particles when they hit the detection screen.
Now, let’s discuss Wheeler’s twist. The decision to observe or not doesn’t need to be premeditated. Photons (or electrons) can pass through a slit system and remain until reaching an imaging screen. The experimenter can even opt to glance back in time to see which slit a photon originated from. Known as a delayed choice experiment, this setup has been executed and yielded anticipated outcomes. When the experimenter decides to observe, the photons fail to coalesce into a striped pattern. The essence of the phenomenon is that the reality that It was—whether the light behaves like a wave traversing both slits or a particle going through one—is contingent on the later choice of the experimenter. For clarity, in real studies, the “selections” are automated and randomized to prevent biases, occurring more swiftly than human response times.
In delayed choice experiments, the past remains unchanged. Instead, without experimentation, multiple pasts exist, intertwining distinct realities. Your measurement choice narrows down this history. While a unique past remains elusive, the number of possibilities can be reduced. Thus, this experiment is frequently referred to as the quantum eraser experiment.
Although the time used in actual experiments is merely nanoseconds, in principle, it could reach back to the dawn of the universe. This is what lay behind Wheeler’s intriguing query regarding retaining the ghost of a photon. He envisaged a distant cosmic light source being gravitationally lensed from our view by an intervening black hole, with two light paths bending around opposite sides of the black hole before converging on Earth. This scenario resembles a two-slit experiment on a cosmic scale, where a photon’s ghost may arrive via one path while another, possibly longer, route carries a different one. To execute such a cosmic interference experiment, like Young’s original experiment, the first ghost must be preserved, or “held,” allowing the waves to overlap simultaneously, awaiting the arrival of the second ghost before they merge.
Einstein claimed that past, present, and future are mere illusions. In this case, he erred in specifying “the”. A While the past is recorded in today’s history, it comprises myriad interwoven “ghost pasts,” collectively creating unique narratives on a macroscopic level. Nevertheless, at a quantum level, it transforms into a mosaic of blurred partial realities that exceed human comprehension.
Paul Davies is a theoretical physicist, cosmologist, astrobiologist, and bestselling author. His book, Quantum 2.0, will be published by Penguin in November 2025.
This website uses cookies so that we can provide you with the best user experience possible. Cookie information is stored in your browser and performs functions such as recognising you when you return to our website and helping our team to understand which sections of the website you find most interesting and useful.
Strictly Necessary Cookies
Strictly Necessary Cookie should be enabled at all times so that we can save your preferences for cookie settings.
