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Adapted from an article run in ÃÛÌÒ´«Ã½Æƽâ°æÏÂÔØ Today by Daniel Strain

A team led by RASEI Fellow Ivan Smalyukh has discovered a new type of liquid crystal that exists in perpetual, rhythmic motion, creating, for the first time, time crystals visible to the naked eye.

Reporting their findings in , the team demonstrates how liquid crystals, the same materials found in your phone display, can form a phase of matter that spontaneously breaks both space and time symmetries. Unlike previous time crystals that existed only in quantum systems invisible to the naked eye, these can be observed directly under a microscope.

The researchers designed special glass cells filled with liquid crystals and coated with light-sensitive dye molecules. When illuminated with blue light, something remarkable happens: like dancers following a lead, the liquid crystal molecules respond to cues from the dye molecules, creating an elaborate molecular waltz that repeats its steps over and over.

Here's how the molecular choreography works: The azobenzene dye molecules at the surface respond to light by rotating, which then guides neighboring liquid crystal molecules to reorient. This creates a feedback loop where the changing liquid crystal orientation affects how light polarizes as it passes through, which then influences more dye molecules at the bottom surface. The result is a self-sustaining temporal rhythm.

The researchers discovered that these time crystals are built from special molecular arrangements called ‘topological solitons’, think of it like stable whirlpools in a stream that maintain their shape while the water flows around them. These soliton "particles" interact with each other through the liquid crystal's elasticity, forming arrays that oscillate in time with remarkable precision.

What makes these time crystals remarkable is their resilience, similar to a heartbeat that continues despite disturbances, these patterns persist even when perturbed. The team demonstrated that the crystals maintain their rhythm when subjected to random light fluctuations and recover their ordered state after disruptions, meeting stringent criteria that distinguish true time crystals from simple periodic behavior.

The temporal periods can be tuned from milliseconds to tens of seconds by adjusting temperature and light intensity, while the spatial patterns can extend over areas larger than a square millimeter—making them easily visible and potentially practical for applications.

There are many potential applications, particularly in optoelectronics and security. The time crystals could serve as dynamic optical elements that modulate light in both space and time, enable new forms of optical communication, or provide sophisticated anti-counterfeiting features through their unique spatiotemporal "fingerprints." The ability to create 2+1 dimensional barcodes (two spatial dimensions plus time) could revolutionize information storage and encoding.

As is often found with breakthrough discoveries, the most transformative applications are likely yet to be imagined. But for now, scientists have created matter that literally keeps time.