Information propagation through quantum chains with fluctuating disorder

TL;DR

This paper explores how fluctuating external fields affect information transfer in quantum chains, revealing suppression mechanisms, a noise threshold for ballistic propagation, and localization phenomena distinct from static disorder effects.

Contribution

It introduces a detailed analysis of information propagation under fluctuating disorder, identifying a noise threshold for ballistic transport and contrasting localization effects with static disorder scenarios.

Findings

Existence of a noise threshold for ballistic information propagation.

Localization occurs for all levels of unobservable noise.

Observable fluctuating fields can induce diffusive information spread.

Abstract

We investigate the propagation of information through one-dimensional quantum chains in fluctuating external fields. We find that information propagation is suppressed, but in a quite different way compared to the situation with static disorder. We study two settings: (i) a general model where an unobservable fluctuating field acts as a source of decoherence; (ii) the XX model with both observable and unobservable fluctuating fields. In the first setting we establish a noise threshold below which information can propagate ballistically and above which information is localised. In the second setting we find localisation for all levels of unobservable noise, whilst an observable field can yield diffusive propagation of information.