Observation of a dissipative time crystal

TL;DR

This paper reports the first experimental observation of a dissipative time crystal in an atom-cavity system, demonstrating a stable, period-doubled density wave pattern induced by controlled dissipation and interactions.

Contribution

It provides the first experimental realization of a dissipative time crystal, highlighting the role of dissipation in stabilizing spatiotemporal order.

Findings

Observation of a period-doubled chequerboard density wave pattern

Robustness of the time crystal against parameter changes

Demonstration of dissipation as a key ingredient in time crystal formation

Abstract

The formation of a phase of matter can be associated with the spontaneous breaking of a symmetry. For crystallization, this broken symmetry is the spatial translation symmetry, as the atoms spontaneously localize in a periodic fashion. In analogy to spatial crystals, the spontaneous breaking of temporal translation symmetry results in the formation of time crystals. While recent and on-going experiments on driven isolated systems aim to minimize dissipative processes, as it is an undesired source of decay, well-designed dissipation has been put forth as a constitutive ingredient in the formation of dissipative time crystals (DTCs). Here, we present the first experimental realisation of a DTC, implemented in an atom-cavity system. Its defining feature is a period doubled switching between distinct chequerboard density wave patterns, induced by controlled cavity-dissipation and cavity-mediated interactions. We demonstrate the robustness of this phase against system parameter changes and temporal perturbations of the driving. Our work provides a framework for realising phases of matter with spatiotemporal order in presence of dissipation. We note that this is the natural environment of matter, and therefore shapes its physical phenomena profoundly, making its study imperative.