Many-body Non-Hermitian Skin Effect At Finite Temperatures

TL;DR

This paper explores the many-body non-Hermitian skin effect at finite temperatures, revealing unique behaviors such as real-space Fermi surfaces, corner condensation of bosons, and a novel phase transition without Goldstone modes.

Contribution

It uncovers the distinct many-body non-Hermitian skin effect at finite temperatures and its implications for fermionic and bosonic systems, including phase transitions and symmetry breaking.

Findings

Fermionic systems exhibit a real-space Fermi surface due to the skin effect.

Bosonic systems show condensation in corners with decay rates exceeding exponential.

A phase transition with spontaneous U(1) symmetry breaking occurs without Goldstone modes.

Abstract

In this study, we investigate the many-body non-Hermitian skin effect at finite temperatures in the thermodynamic limit. Our findings indicate an interesting correspondence between the non-Hermitian skin effect and a linear electric potential effect in this case. This correspondence leads to a unique distribution in non-Hermitian systems; particles in these many-body non-Hermitian systems do not inhabit the energy eigenstates of their single-body counterparts. As a result, the many-body non-Hermitian skin effect is significantly different from the single-body non-Hermitian skin effect. Specifically, for fermionic systems, the non-Hermitian skin effect disrupts the original phase, leading to a real-space Fermi surface. For bosonic systems, it can direct bosons to condense in corners at a decay rate that surpasses exponential, even at high temperatures. It also triggers a remarkable phase transition, resulting in spontaneous U(1) symmetry breaking. Uniquely, this does not generate a Goldstone mode, presenting a deviation from traditional expectations as per the Goldstone theorem.