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.
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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
Source: www.sci.news
