Time crystals tick: a new route toward ultra-precise and accurate quantum clocks

• The study, published in Physical Review Letters, demonstrates that dissipative quantum time crystals can function as highly accurate and fast clocks, with their performance enhanced by the spontaneous breaking of time-translation symmetry.
• The research is the result of a collaboration between researchers from the Institute for Cross-Disciplinary Physics and Complex Systems (IFISC, UIB-CSIC), the International Centre for Theoretical Physics (ICTP) and the Technical University of Vienna.

A recently discovered phase of matter known as a time crystal could provide a powerful new platform for measuring time at the quantum scale. In a recent paper published in Physical Review Letters, researchers present a theoretical model showing that dissipative time crystals can operate as genuine quantum clocks, combining high accuracy and resolution while keeping energy dissipation remarkably low.

Time crystals are many-body quantum systems that spontaneously organize into periodic motion, even without an external clock setting the rhythm. This unusual behavior, which breaks the fundamental symmetry of time translation, has attracted growing interest over the past decade, mainly for its conceptual significance and its emerging role in quantum sensing. The new study takes this line of research a decisive step further by showing how time crystals can be directly harnessed for time-keeping.

The authors propose a quantum clock built from a large collection of interacting spins coupled to a non-equilibrium environment. When this system is continuously monitored, its time-crystalline dynamics become visible through a stream of detectable events. By counting the photons emitted by the spins, the clock produces stochastic “ticks” that can be used to define a time reference. Crucially, as the number of spins increases, this signal becomes both more regular and macroscopic, improving the clock’s performance rather than washing it out.

“Our results show that time crystals are not only a fascinating phase of matter, but they may also be of practical use”, says Gonzalo Manzano, researcher at IFISC (UIB-CSIC) and a leading author of the study. “The spontaneous oscillations of the time-crystal phase translate into a clock signal that is both fast and precise, and whose quality improves collectively as the system grows. It is an example of how the complexity of a physical system can be used as a resource”.

The team systematically analyzes the clock’s performance using well-established figures of merit such as their resolution (how fast the clock produces ticks) and their accuracy (how similar those ticks are). They find that once the system enters the time-crystal regime, the usual trade-off between these quantities is strongly modified. In particular, the clock can outperform classical benchmarks thanks to correlations induced by time-translation symmetry breaking.

Beyond time-keeping performance, the work also addresses a fundamental question: what is the energy cost of measuring time? Any functioning clock in contact with the environment must dissipate energy, and understanding this cost is essential for future quantum technologies. The researchers develop new techniques to assess this cost and show that the accuracy of a quantum clock is directly linked to the amount of entropy it produces. These techniques are based on Martingale theory, a mathematical framework that has proven already useful in different contexts, from finance to stochastic thermodynamics. In this way, the study provides a clear thermodynamic way to evaluate how efficiently time can be measured at the quantum level.

“Martingale theory has been crucial to assess thermodynamic costs at stochastic times, such as the times at which the clock produces a tick”, explains Manzano. “It offers a clear framework to assess how efficiently a quantum clock operates, something that is attracting a lot of attention”.

According to the authors, the proposed time-crystal clock can operate in an ultra-fast, accurate and relatively low-dissipation regime making it a promising candidate for future quantum timing devices. The concepts and methods introduced in the work are general and may apply to a broad class of driven-dissipative quantum systems.

Looking ahead, the researchers expect their results to stimulate further studies on the use of time crystals in quantum technologies, from precision time-keeping to sensing and beyond. By linking fundamental symmetry breaking to thermodynamic performance, the work opens a new perspective on how exotic phases of matter can be turned into functional quantum devices.

L. Viotti, M. Huber, R. Fazio, and G. Manzano. Quantum Time-Crystal Clock and its Performance, Physical Review Letters (2026). DOI: https://doi.org/10.1103/dj21-gmdj