Kinetic constraints, hierarchical relaxation and onset of glassiness in strongly interacting and dissipative Rydberg gases

TL;DR

This paper demonstrates how strongly interacting, dissipative Rydberg gases exhibit glass-like relaxation dynamics due to kinetic constraints, with the relaxation behavior tunable by interaction strength and affected by spontaneous decay.

Contribution

It introduces a master equation with kinetic constraints for Rydberg gases, revealing glassy dynamics and non-equilibrium states in these quantum systems.

Findings

Spatially correlated relaxation similar to glasses

Relaxation time depends on interaction strength

Spontaneous decay leads to non-equilibrium stationary states

Abstract

We show that the dynamics of a laser driven Rydberg gas in the limit of strong dephasing is described by a master equation with manifest kinetic constraints. The equilibrium state of the system is uncorrelated but the constraints in the dynamics lead to spatially correlated collective relaxation reminiscent of glasses. We study and quantify the evolution towards equilibrium in one and two dimensions, and analyze how the degree of glassiness and the relaxation time are controlled by the interaction strength between Rydberg atoms. We also find that spontaneous decay of Rydberg excitations leads to an interruption of glassy relaxation that takes the system to a highly correlated non-equilibrium stationary state. The results presented here, which are in principle also applicable other systems such as polar molecules and atoms with large magnetic dipole moments, show that the collective behavior of cold atomic and molecular ensembles can be similar to that found in soft condensed-matter systems.