Time crystallinity and finite-size effects in clean Floquet systems

Andrea Pizzi, Daniel Malz, Giuseppe De Tomasi, Johannes Knolle, Andreas Nunnenkamp

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

A cornerstone assumption that most literature on discrete time crystals has relied on is that homogeneous Floquet systems generally heat to a featureless infinite temperature state, an expectation that motivated researchers in the field to mostly focus on many-body localized systems. Some works have, however, shown that the standard diagnostics for time crystallinity apply equally well to clean settings without disorder. This fact raises the question whether a homogeneous discrete time crystal is possible in which the originally expected heating is evaded. Studying both a localized and an homogeneous model with short-range interactions, we clarify this issue showing explicitly the key differences between the two cases. On the one hand, our careful scaling analysis confirms that, in the thermodynamic limit and in contrast to localized discrete time crystals, homogeneous systems indeed heat. On the other hand, we show that, thanks to a mechanism reminiscent of quantum scars, finite-size homogeneous systems can still exhibit very crisp signatures of time crystallinity. A subharmonic response can in fact persist over timescales that are much larger than those set by the integrability-breaking terms, with thermalization possibly occurring only at very large system sizes (e.g., of hundreds of spins). Beyond clarifying the emergence of heating in disorder-free systems, our work casts a spotlight on finite-size homogeneous systems as prime candidates for the experimental implementation of nontrivial out-of-equilibrium physics.

Original languageEnglish
Article number214207
JournalPhysical Review B
Volume102
Issue number21
DOIs
StatePublished - 29 Dec 2020

Fingerprint

Dive into the research topics of 'Time crystallinity and finite-size effects in clean Floquet systems'. Together they form a unique fingerprint.

Cite this