Quantum Computers Are Now Practical and Valuable

Amidst the excitement surrounding quantum computing, the technology may appear as a catch-all solution for various challenges. While the science is impressive, real-world applications are still developing. However, the quest for viable uses is starting to yield fruitful results. Particularly, the search for exotic quantum materials is gaining traction, which could revolutionize electronics and enhance computational power.

The discovery and exploration of new phases—especially more exotic forms analogous to ice or liquid water—remain foundational to condensed matter physics. Insights gained here can enhance our understanding of semiconductor functionality and lead to practical superconductors.

Yet, traditional experimental methods are increasingly inadequate for studying certain complex phases that theory suggests exist. For instance, the Kitaev honeycomb model predicts materials with a unique type of magnetism, but it took “decades of exploration to actually design this with real materials,” according to Simon Everred of Harvard University.

Everred and colleagues simulated this phenomenon using a quantum computer with 104 qubits made from ultra-cold atoms. They’re not alone in this endeavor; Frank Pollmann from the Technical University of Munich and his team utilized Google’s Sycamore and Willow Quantum Computers, which house 72 and 105 superconducting qubits respectively, to model conditions based on iterations of the Kitaev honeycomb framework. Both teams have documented their findings.

“These two projects harness quantum computers to investigate new phases of problems that had been theoretically predicted but not observed experimentally,” notes Petr Zapletal from the University of Erlangen-Nuremberg, who was not involved in the studies. “The advancement of quantum simulations for complex condensed matter systems is particularly thrilling.”

Both research teams confirmed the presence of anyons in their simulations, a significant progress that illustrates the growth and potential utility of quantum computers. Anyons differ fundamentally from qubits and represent exotic particles that are challenging to emulate.

Existing particles typically categorize into fermions and bosons. While chemists and materials scientists often focus on fermions, qubits generally function as bosons. The distinctions—like spin and collective behaviors—complicate the simulation of fermions using bosons. However, cold atom quantum experiments utilized Kitaev models to bridge these gaps. Masin Karinowski of Harvard, who participated in the research, described the Kitaev model as a “canvas” for exploring new physics. Through this model, the team could tune quasiparticles in their simulations by adjusting interactions among the qubits. According to Karinowski, some of these new particles might be employed to replicate novel materials.

Another critical aspect of the research was the use of Google’s quantum computer to examine materials outside equilibrium. Despite the significant exploration of equilibrium states in laboratories, the non-equilibrium realm remains largely uncharted. Pollmann notes that this aligns with laboratory trials where materials are repeatedly subjected to laser pulses. His team’s work reflects how condensed matter physicists study materials by exposing them to extreme temperatures or magnetic fields and then diagnosing changes in their phases. Such diagnostics are crucial for determining the conditions under which materials can be effectively utilized.

It’s important to clarify that these experiments don’t yield immediate real-world applications. To translate these findings into usable technologies, researchers will need to conduct further analysis on larger, less error-prone quantum computers. However, these preliminary studies carve out a niche for quantum computers in exploring physical phenomena, akin to the way traditional experimental tools have been employed for decades.

That material science might be the first field to showcase the value of quantum computing is not surprising. This aligns with how pioneers like Richard Feynman discussed quantum technology in the 1980s, envisioning its potential beyond mere devices. Moreover, this perspective diverges from the usual portrayal of quantum computing as technology primarily focused on outperforming classical computers in non-practical tasks.

“Viewing the advancement of quantum computing as a scientific approach, rather than simply through the lens of individual device performance, is undeniably supported by these experimental findings,” concludes Kalinowski.