Phase coherence in out-of-equilibrium supersolid states of ultracold dipolar atoms

TL;DR

This paper studies how out-of-equilibrium excitations affect phase coherence in supersolid states of ultracold dipolar atoms, revealing rapid rephasing and insights into phase boundaries.

Contribution

It provides experimental insights into the non-equilibrium dynamics and phase re-establishment in supersolids created with ultracold dipolar gases.

Findings

Rapid re-establishment of phase coherence after excitations

Identification of phase boundary between solid-like and supersolid states

Evidence of superfluid flow across the sample

Abstract

A supersolid is a fascinating phase of matter, combining the global phase coherence of a superfluid with hallmarks of solids, e.g. a spontaneous breaking of the translational symmetry. Recently, states with such counter-intuitive properties have been realized in experiments using ultracold quantum gases with strong dipolar interactions. Here, we investigate the response of a supersolid state to phase excitations which shatter the global phase coherence. After the creation of those excitations, we observe a rapid re-establishment of a global phase coherence, suggesting the presence of a superfluid flow across the whole sample and an efficient dissipation mechanism. We are able to identify a well-defined region where rephasing occurs, indicating the phase boundary between the solid-like and the supersolid phase. Our observations call for the development of theoretical descriptions able to capture the non-equilibrium dynamics in the recently discovered supersolid states of quantum matter.