Dissipative discrete time crystals

TL;DR

This paper reports the experimental observation of a dissipative discrete time crystal in a driven quantum spin system, demonstrating stable subharmonic response and exploring the role of dissipation in stabilizing non-equilibrium phases.

Contribution

The study provides the first experimental realization of a dissipative discrete time crystal in a solid-state system and introduces a theoretical model explaining its stability.

Findings

Stable subharmonic peak at half the drive frequency observed

Dissipation plays a key role in stabilizing the DTC order

Theoretical phase diagram matches experimental results

Abstract

Periodically driven quantum systems host a range of non-equilibrium phenomena which are unrealizable at equilibrium. Discrete time-translational symmetry in a periodically driven many-body system can be spontaneously broken to form a discrete time crystal, a putative quantum phase of matter. We present the observation of discrete time crystalline order in a driven system of paramagnetic $P$ -donor impurities in isotopically enriched $^{28}Si$ cooled below $10$ K. The observations exhibit a stable subharmonic peak at half the drive frequency which remains pinned even in the presence of pulse error, a signature of DTC order. We propose a theoretical model based on the paradigmatic central spin model which is in good agreement with experimental observations, and investigate the role of dissipation in the stabilisation of the DTC. Both experiment and theory indicate that the order in this system is primarily a dissipative effect, and which persists in the presence of spin-spin interactions. We present a theoretical phase diagram as a function of interactions and dissipation for the central spin model which is consistent with the experiments. This opens up questions about the interplay of coherent interaction and dissipation for time-translation symmetry breaking in many-body Floquet systems.