Interaction-induced decoherence in non-Hermitian quantum walks of ultracold Bosons

TL;DR

This paper investigates how particle interactions induce decoherence in non-Hermitian quantum walks of ultracold bosons, revealing the transition from quantum coherence to classical incoherence through topological and rate equation analyses.

Contribution

It introduces a topological measure to distinguish coherent from incoherent dynamics in interacting non-Hermitian quantum walks, and provides a quantitative rate equation model for nonlinear incoherent behavior.

Findings

Topological transition characterizes the shift from quantum to classical dynamics.

Interaction causes decoherence, breaking translational symmetry.

Rate equations accurately describe incoherent nonlinear dynamics.

Abstract

We study the influence of particle interaction on a quantum walk on a bipartite one-dimensional lattice with decay from every second site. The corresponding non-interacting (linear) system has been shown to have a topological transition described by the average displacement before decay. Here we use this topological quantity to distinguish coherent quantum dynamics from incoherent classical dynamics caused by a breaking of the translational symmetry. We furthermore analyze the behavior by means of a rate equation providing a quantitative description of the incoherent nonlinear dynamics.