Correlation versus dissipation in a non-Hermitian Anderson impurity model

TL;DR

This paper investigates how strong correlations and dissipation interact in a non-Hermitian Anderson impurity model, revealing a dissipative quantum phase transition and a crossover between regimes, with implications for quantum dot and cold atom systems.

Contribution

It develops a slave-boson theory for a non-Hermitian Anderson model, uncovering how correlations modify dissipation and induce a quantum phase transition.

Findings

Strong correlations suppress effective one-body loss in the Kondo regime.

A dissipative quantum phase transition enhances impurity lifetime.

Crossover from Kondo to valence fluctuation regime driven by dissipation.

Abstract

We analyze the competition between strong correlations and dissipation in quantum impurity systems from the Kondo regime to the valence fluctuation regime by developing a slave-boson theory for a non-Hermitian Anderson impurity model with one-body loss. Notably, in the non-Hermitian Kondo regime, strong correlations qualitatively change the nature of dissipation through renormalization effects, where the effective one-body loss is suppressed and emergent many-body dissipation characterized by the complex-valued hybridization is generated. We unveil the mechanism of a dissipative quantum phase transition of the Kondo state on the basis of this renormalization effect, which counterintuitively enhances the lifetime of the impurity against loss. We also find a crossover from the non-Hermitian Kondo regime to the valence fluctuation regime dominated by one-body dissipation. Our results can be tested in a wide variety of setups such as quantum dots coupled to electronic leads and quantum point contacts in ultracold Fermi gases.