Researchers Create Classical Time Crystal Using Speakers and Styrofoam
Exotic states of matter known as time crystals have long been considered a quantum phenomenon. However, a recent study by a team from New York University (NYU) has demonstrated that a classical time crystal can emerge in a much simpler way – using only speakers and styrofoam.
This system not only provides an exceptionally clean example of a classical time crystal but also serves as a fascinating laboratory for studying non-reciprocal interactions on a macroscopic scale, where particles interact through scattered sound waves rather than direct, balanced forces.
NYU physicist David Grier expressed his excitement about the discovery, stating, “Time crystals are fascinating not only because of the possibilities, but also because they seem so exotic and complicated. Our system is remarkable because it’s incredibly simple.”

Time crystals, first predicted in 2012, are a unique phenomenon characterized by patterns that repeat in time, breaking time symmetry without external influence. While many experimental time crystals are quantum systems, Grier and his team accidentally discovered a classical system while studying non-reciprocal interactions.
The researchers used tiny polystyrene beads to study indirect interactions via sound waves, leveraging their lightweight and structural integrity. By creating a standing sound wave with a speaker array and introducing the beads, they observed a non-reciprocal interaction that led to the emergence of a temporal pattern akin to a time crystal.
These findings, published in Physical Review Letters, not only provide insights into exotic behaviors of matter but also demonstrate that complex phenomena can be studied using simple, accessible tools. The implications of this research could extend to various fields, including biology, where non-reciprocal interactions are prevalent.
While practical applications are yet to be determined, the simplicity and effectiveness of this setup highlight the potential for exploring unconventional physical phenomena with basic materials. This groundbreaking research opens up new avenues for investigating the intriguing world of time crystals and non-reciprocal interactions.

