Out-of-equilibrium steady states of a locally driven lossy qubit array

TL;DR

This paper explores the complex steady states of a driven, lossy qubit array, revealing phenomena like long-range coherence and density-wave order, with implications for engineering nonequilibrium phases in photonic systems.

Contribution

It uncovers how varying dissipation can induce long-range coherence and density-wave order, providing new insights into nonequilibrium phases in qubit arrays.

Findings

Increasing pump and loss rates can establish long-range coherence.

Strong dissipation can generate correlation and density-wave order.

Steady states differ between hard-core bosons and free fermions.

Abstract

We find a rich variety of counterintuitive features in the steady states of a qubit array coupled to a dissipative source and sink at two arbitrary sites, using a master equation approach. We show there are setups where increasing the pump and loss rates establishes long-range coherence. At sufficiently strong dissipation, the source or sink effectively generates correlation between its neighboring sites, leading to a striking density-wave order for a class of "resonant" geometries. This effect can be used more widely to engineer nonequilibrium phases. We show the steady states are generically distinct for hard-core bosons and free fermions, and differ significantly from the ones found before in special cases. They are explained by generally applicable ansatzes for the long-time dynamics at weak and strong dissipation. Our findings are relevant for existing photonic setups.