Non-Hermitian Stark Many-Body Localization

TL;DR

This paper explores phase transitions in a non-Hermitian, non-reciprocal interacting boson model under a Stark potential, revealing that spectral real-complex transition occurs before the many-body localization transition, indicating a novel non-MBL-driven spectral transition.

Contribution

It uncovers a new spectral real-complex transition in a disorder-free non-Hermitian system, distinct from the MBL transition, using exact diagonalization techniques.

Findings

Spectral RC transition precedes MBL transition.

Spectral real-complex transition is non-MBL-driven.

Phase diagrams show distinct transition points.

Abstract

Utilizing exact diagonalization (ED) techniques, we investigate a one-dimensional, non-reciprocal, interacting hard-core boson model under a Stark potential with tail curvature. By employing the non-zero imaginary eigenenergies ratio, half-chain entanglement entropy, and eigenstate instability, we numerically confirm that the critical points of spectral real-complex (RC) transition and many-body localization (MBL) phase transition are not identical, and an examination of the phase diagrams reveals that the spectral RC transition arises before the MBL phase transition, which suggests the existence of a novel non-MBL-driven spectral RC transition. These findings are quite unexpected, and they are entirely different from observations in disorder-driven interacting non-Hermitian systems. This work provides a useful reference for further research on phase transitions in disorder-free interacting non-Hermitian systems.