Diffusive to non-ergodic dipolar transport in a dissipative atomic medium

TL;DR

This paper explores how dipolar transport of Rydberg impurities in an ultracold atomic gas transitions from diffusive to non-ergodic behavior under dissipation, revealing potential for studying localization phenomena.

Contribution

It demonstrates the control of impurity spreading via dissipation and reveals non-ergodic extended phases in a long-range hopping system with tunable dissipation.

Findings

Diffusive spreading controlled by probe laser intensity.

Spreading frozen when dressing fields are turned off.

Numerical simulations indicate a non-ergodic extended phase.

Abstract

We investigate the dipole mediated transport of Rydberg impurities through an ultracold gas of atoms excited to an auxiliary Rydberg state. In one experiment we continuously probe the system by coupling the auxiliary Rydberg state to a rapidly decaying state which realizes a dissipative medium. In-situ imaging of the impurities reveals diffusive spreading controlled by the intensity of the probe laser. By preparing the same density of hopping partners but then switching off the dressing fields the spreading is effectively frozen. This is consistent with numerical simulations which indicate the coherently evolving system enters a non-ergodic extended phase due to disorder. This opens the way to study transport and localization phenomena in systems with long-range hopping and controllable dissipation.