Interplay between non-Fermi liquid and non-Hermiticity: A multi-method study of non-Hermitian multichannel Kondo model

TL;DR

This study explores the complex interplay of non-Fermi liquid and non-Hermitian physics in a multichannel Kondo model, combining experimental proposals and multi-method theoretical analysis to reveal novel quantum phenomena.

Contribution

It introduces an experimental setup for the non-Hermitian multichannel Kondo model and provides a comprehensive multi-method analysis revealing new quantum states and behaviors.

Findings

Identification of Yu-Shiba-Rusinov-like states in the non-Hermitian regime

Numerical signatures of these states in strong non-Hermiticity

Anomalous temperature dependence of Kondo conductance beyond Hermitian systems

Abstract

Non-Hermitian multichannel Kondo problems host both non-Fermi liquid and non-Hermitian physics, which provide a prototypical model to explore exotic collective quantum phenomena driven by the two different ingredients. Here, we first propose an experimental setup that realizes this model with exact channel symmetry as well as a controllable PT symmetry. Then, we perform a multi-method study of this model, focusing on the low-energy spectrum, the thermodynamic quantities, and the transport properties associated with different fixed points. Using the Bethe ansatz approach, we identify existence of the Yu-Shiba-Rusinov-like state previously found in the non-Hermitian single-channel Kondo model. Then, based on non-Hermitian numerical renormalization group calculations, we reveal clear numerical signatures of the Yu-Shiba-Rusinov state emerging in the relatively strong non-Hermiticity regime of the PT-asymmetric model. Furthermore, our boundary conformal field theory, which is found to be applicable for the PT-symmetric model, uncovers an anomalous temperature dependence of the Kondo conductance, which is beyond conventional Hermitian Kondo systems.