New calculations suggest that time crystals, once seen as a quantum oddity, might serve as building blocks for highly precise quantum clocks. Researchers analyzed systems of quantum particles and found that time crystals maintain accuracy better when measuring short time intervals compared to conventional phases. This development could offer alternatives to existing timekeeping technologies.
Time crystals represent a peculiar phenomenon in quantum physics, characterized by structures that repeat in time rather than space. Unlike ordinary crystals with repeating atomic patterns, time crystals spontaneously cycle through configurations without external forcing, akin to water freezing into ice at low temperatures.
A team led by Ludmila Viotti at the Abdus Salam International Centre for Theoretical Physics in Italy examined a system involving up to 100 quantum particles, each with two spin states, similar to a coin's heads or tails. This setup can operate in a time crystal phase, with spontaneous oscillations, or a normal phase without such cycling. The researchers evaluated the clock performance—accuracy and precision—in both states.
"In the normal phase, if you want to resolve smaller intervals of time, you will lose accuracy exponentially. In the time crystalline phase, for the same resolution, you can get much higher accuracy," Viotti explained. Typically, spin-based clocks degrade in precision for shorter measurements, like seconds versus minutes, but this issue diminishes in the time crystal configuration.
Mark Mitchison at King’s College London noted that while time crystals intuitively suit clock-making due to their inherent oscillations, a detailed analysis of their advantages was previously lacking. His prior work demonstrated that almost any event sequence can form a clock, yet self-sustaining rhythms provide a stronger foundation.
Krzysztof Sacha at the Jagiellonian University in Poland highlighted that time crystals have been known for about a decade, but practical applications remain elusive. He compared them to conventional crystals used in jewelry and processors, expressing hope for similar technological uses.
Such clocks are unlikely to surpass the world's most advanced ones, based on ultracold atoms, but could rival satellite-dependent systems like GPS, which are vulnerable to interference. Additionally, time crystal clocks might detect magnetic fields, as disruptions would alter their rhythm. However, Viotti emphasized the need for further comparisons with other clock systems and experimental validation using real spins.
The findings appear in Physical Review Letters.