Nonequilibrium steady state transport of collective-qubit system in strong coupling regime

TL;DR

This paper studies steady state photon transport in a collective-qubit system under strong coupling, revealing size-dependent flux and noise relations, and a universal finite-size scaling law for coupling strength.

Contribution

It introduces a nonperturbative approach to analyze nonequilibrium transport in strong coupling regimes, highlighting the role of indirect qubit interactions mediated by photonic baths.

Findings

Linear relation of flux and noise power with system size

Finite-size scaling of coupling strength follows an inverse power-law

Universal behavior in strong coupling photon-qubit systems

Abstract

We investigate the steady state photon transport in a nonequilibrium collective-qubit model. By adopting the noninteracting blip approximation, which is applicable in the strong photon-qubit coupling regime, we describe the essential contribution of indirect qubit-qubit interaction to the population distribution, mediated by the photonic baths. The linear relations of both the optimal flux and noise power with the qubits system size are obtained. Moreover, the inversed power-law style for the finite-size scaling of the optimal photon-qubit coupling strength is exhibited, which is proposed to be universal.