Physicists Create Levitating Form of Time Crystal
A team of scientists at New York University has created a version of the exotic phase of matter in which particles levitate acoustically and interact by exchanging sound waves.
Morrell et al. observed a new type of time crystal, whose particles levitate on a sound cushion while interacting with each other by exchanging sound waves. Image credit: David Song / NYU.
Time crystals – a set of particles that “tick” – hold great promise for advancing quantum computing and data storage, among other uses.
The particles of the new type of time crystal defy Newton’s third law of motion, which states that for every action of an object, there is an equal and opposite reaction, meaning that forces always occur in balanced pairs (i.e. equal in magnitude and opposite in direction).
On the other hand, these particles interact more independently and are not necessarily linked to balanced forces: they move in a non-reciprocal manner.
Notably, these time crystals, visible to the naked eye, hang from a foot-tall device that you can hold in your hand.
“Speakers emit sound waves, which allows us to place small particles in the pressure nodes of the wave, where they are levitated against gravity,” said New York University student Leela Elliott.
The team’s time crystal is made of polystyrene balls suspended by sound waves, which serve as an “acoustic levitator” to initially hold the balls still in the air.
“We discovered that a very simple system of two particles levitated in an acoustic standing wave can produce spontaneous oscillations and a temporal crystal effect through their unbalanced interactions,” said New York University graduate student Mia Morrell.
“When these levitating particles interacted with each other, they did so by exchanging scattered sound waves.”
“Specifically, larger particles scatter more sound than smaller particles.”
“Therefore, a large particle will influence a small particle more than the small particle will influence the large particle.”
“As a result, the interaction between a small and a large particle is unbalanced.”
“Think of two ferries of different sizes approaching a dock.”
“Each makes waves that push the other – but to different degrees, depending on their size.”
The results expand the prospects that these crystals offer to technology and industry.
“Time crystals are much more autonomous in the sense that they choose everything for themselves and continue to function,” said Professor David Grier of New York University.
“They are fascinating not only because of their possibilities, but also because they seem so exotic and complicated.”
“Our system, on the other hand, is remarkable because it is incredibly simple.”
The results were published in the journal Physical Examination Letters.
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Mia C. Morrell and others. 2026. Non-reciprocal wave-mediated interactions power a classical time crystal. Phys. Reverend Lett 136, 057201; doi: 10.1103/zjzk-t81n
