Localization-delocalization effects of a delocalizing dissipation on disordered XXZ spin chains

TL;DR

This study explores how dissipation influences localization in disordered XXZ spin chains, revealing regimes where dissipation enhances coherence and affects the localization-delocalization transition.

Contribution

It demonstrates that dissipation can both localize and delocalize states in disordered XXZ spin chains, depending on interaction strength and disorder, providing new insights into open quantum systems.

Findings

Strong disorder can lead to localized steady states despite dissipation.

Weak interactions with intermediate disorder show exponential decay in occupation.

Strong dissipation increases coherence and reduces localization signatures.

Abstract

The interplay between interaction, disorder, and dissipation has shown a rich phenomenology. Here we investigate a disordered XXZ spin chain in contact with a bath which, alone, would drive the system towards a highly delocalized and coherent Dicke state. We show that there exist regimes for which the natural orbitals of the single-particle density matrix of the steady state are all localized in the presence of strong disorders, either for weak interaction or strong interaction. We show that the averaged steady-state occupation in the eigenbasis of the open system Hamiltonian could follow an exponential decay for intermediate disorder strength in the presence of weak interactions, while it is more evenly spread for strong disorder or for stronger interactions. Last, we show that strong dissipation increases the coherence of the steady states, thus reducing the signatures of localization. We capture such signatures of localization also with a concatenated inverse participation ratio which simultaneously takes into account how localized are the eigenstates of the Hamiltonian, and how close is the steady state to an incoherent mixture of different energy eigenstates.