Original title: Discrete time crystals in disordered anisotropic Heisenberg chains
Francesco Formicola, Grazia Di Bello, Antonio De Candia, Giulio De Filippis +1 · September 2026
Normally, if you poke a quantum system on a regular timer, it responds at that exact same rhythm. Scientists want to know when systems break this rule and form discrete time crystals, which repeat at a slower rhythm instead. Researchers studied this in periodically driven, strongly disordered chains of interacting quantum spins. They started in a state where disorder traps energy and prevents heat flow. Then, they pulsed the system with sharp rotational kicks. Even with these kicks, the spins reacted at half the driving frequency, ticking at twice the original period. When the researchers introduced rotation errors, they tested the stability of this slow ticking and identified an in-between phase that behaves like weakly correlated particles before the time crystal breaks down.
You are bouncing a ball on the ground at a steady beat. Each bounce is a sharp impact. Normally, the ball comes up and down with each bounce. But in some conditions, the ball might bounce only every other time, so it hits the ground every two beats instead of every beat. In this paper, a quantum system is kicked periodically, but it exhibits a response at half the driving frequency, similar to the ball bouncing at half the beat.
This work identifies stable conditions for a new phase of matter that breaks time symmetry, which could be important for understanding and controlling quantum systems under periodic driving.
The evidence comes from numerical simulations, not experiments. It only considers rotation-angle errors and not other types of disturbances. The study is restricted to a specific spin chain model.
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Discrete time crystals in disordered anisotropic Heisenberg chains — Francesco Formicola, Grazia Di Bello, Antonio De Candia et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.