Time crystals, a peculiar phenomenon in quantum physics, are emerging as potential building blocks for highly precise timekeeping devices. While conventional crystals are defined by their repeating atomic arrangements, time crystals exhibit a repeating structure in the temporal dimension. When observed over time, these unique materials cycle through a series of configurations repeatedly and spontaneously, not due to external influence but as their inherent preferred state, much like water solidifies into ice at low temperatures.
Recent theoretical work by Ludmila Viotti and her colleagues at the Abdus Salam International Centre for Theoretical Physics in Italy suggests that certain types of time crystals could form the basis for exceptionally accurate quantum clocks.
The researchers mathematically modeled a system comprising up to 100 quantum mechanical particles. Each particle possessed two distinct states, determined by its quantum spin—akin to a coin having a heads or tails side. Their analysis focused on a specific spin system capable of existing either as a time crystal or in a more conventional, non-oscillating state. They then calculated and compared the accuracy and precision of a clock constructed from spins in both these phases.
Viotti explained the findings: “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.” This means that while a standard spin-based clock would naturally decrease in accuracy when attempting to measure shorter durations, a time crystal phase prevents this degradation, maintaining high accuracy regardless of the interval length.
Mark Mitchison from King’s College London commented that while the clock-making potential of time crystals was anticipated, a thorough quantitative assessment was previously lacking. His own research group has demonstrated that nearly any random sequence of events can be engineered into a functional clock, but he highlighted that a system with self-sustaining oscillations inherently provides a more robust clock structure from its inception.
Krzysztof Sacha, based at Jagiellonian University in Poland, noted that despite ten years of knowing about time crystals, their practical applications remain a subject of exploration. “Just as ordinary crystals can be used both for jewelry and for building computer processors, we would like time crystals to enable useful technologies as well,” he stated.
While time crystal-based clocks are unlikely to surpass the accuracy of current atomic clocks, they could offer a viable alternative to satellite-based navigation systems like GPS, which are susceptible to interference. Additionally, Mitchison suggested that such clocks could serve as sensitive detectors for magnetic fields, as even minute fields would disrupt their timing mechanisms.
However, Viotti cautioned that significant further research is required before time crystals can be deployed in practical applications. Her team’s theoretical model needs to be validated against other accurate clock systems and, crucially, tested through experiments with actual spin-based systems.