Many-body critical non-Hermitian skin effect

TL;DR

This paper introduces a new class of many-body critical non-Hermitian skin effect arising from the interplay of non-Hermitian pumping channels and interactions, revealing complex phase transitions and enhanced experimental accessibility.

Contribution

It uncovers a novel many-body critical non-Hermitian skin effect mechanism involving multiple pumping channels and Hubbard interactions, with no single-particle analog.

Findings

Criticality can emerge within bound or scattering states and their mixtures.

Higher-order CSEs appear with more particles, increasing experimental accessibility.

Correlation functions can diagnose the critical phenomena.

Abstract

Criticality in non-Hermitian systems unveils unique phase transitions and scaling behaviors beyond Hermitian paradigms, offering new insights into the interplay between gain/loss, non-reciprocity, and complex energy spectra. In this paper, we uncover a new class of many-body critical non-Hermitian skin effect (CSE) originating from the interplay between multiple non-Hermitian pumping channels and Hubbard interactions. In particular, criticality in the real-to-complex transitions can selectively emerge within the subspace of bound states or scattering states, as well as their interacting admixtures. These mechanisms possess no single-particle analog and can be diagnosed through a specially defined correlation function. As more particles are involved, higher-order CSEs naturally arise, with greatly enhanced effective coupling strengths and hence greater experimental accessibility. Our results reveal an enriched landscape of non-Hermitian critical phenomena in interacting many-body systems, and pave the way for investigating unconventional non-Hermitian criticality in the context of various interaction-induced particle clustering configurations.