Discrete time-crystalline order enabled by quantum many-body scars: entanglement steering via periodic driving

TL;DR

This paper explores how quantum many-body scars enable discrete time-crystalline order in periodically driven systems, offering a new method to control entanglement and stable subharmonic responses in complex quantum dynamics.

Contribution

It introduces a model linking quantum scars to time-crystalline behavior, highlighting the role of spatiotemporal order in Floquet systems and proposing experimental observables.

Findings

Quantum scars enable stable subharmonic responses in driven systems.

Time-crystalline order is linked to initial state dependence, specifically Neel-like states.

Predicted robustness of DTC behavior to perturbations and observable timescales.

Abstract

The control of many-body quantum dynamics in complex systems is a key challenge in the quest to reliably produce and manipulate large-scale quantum entangled states. Recently, quench experiments in Rydberg atom arrays (Bluvstein et. al., arXiv:2012.12276) demonstrated that coherent revivals associated with quantum many-body scars can be stabilized by periodic driving, generating stable subharmonic responses over a wide parameter regime. We analyze a simple, related model where these phenomena originate from spatiotemporal ordering in an effective Floquet unitary, corresponding to discrete time-crystalline (DTC) behavior in a prethermal regime. Unlike conventional DTC, the subharmonic response exists only for Neel-like initial states, associated with quantum scars. We predict robustness to perturbations and identify emergent timescales that could be observed in future experiments. Our results suggest a route to controlling entanglement in interacting quantum systems by combining periodic driving with many-body scars.