Quantum non-equilibrium dynamics of Rydberg gases in the presence of dephasing noise of different strengths

TL;DR

This paper investigates the non-equilibrium dynamics of Rydberg gases under varying dephasing noise, revealing that classical features persist even when quantum coherences are not fully suppressed.

Contribution

It introduces a generalized blockade length to interpolate between quantum and classical regimes and explores the persistence of classical features at intermediate dissipation levels.

Findings

Classical features like the Rydberg blockade radius persist at moderate dephasing.

The excitation density growth follows a power-law behavior similar to the classical limit.

Quantum coherences influence the dynamics but do not eliminate classical phenomena.

Abstract

In the presence of strong dephasing noise the dynamics of Rydberg gases becomes effectively classical, due to the rapid decay of quantum superpositions between atomic levels. Recently a great deal of attention has been devoted to the stochastic dynamics that emerges in that limit, revealing several interesting features, including kinetically-constrained glassy behaviour, self-similarity and aggregation effects. However, the non-equilibrium physics of these systems, in particular in the regime where coherent and dissipative processes contribute on equal footing, is yet far from being understood. To explore this we study the dynamics of a small one-dimensional Rydberg lattice gas subject to dephasing noise by numerically integrating the quantum Master equation. We interpolate between the coherent and the strongly dephased regime by defining a generalised concept of a blockade length. We find indications that the main features observed in the strongly dissipative limit persist when the dissipation is not strong enough to annihilate quantum coherences at the dynamically relevant time scales. These features include the existence of a time-dependent Rydberg blockade radius, and a growth of the density of excitations which is compatible with the power-law behaviour expected in the classical limit.