Probing two-body exceptional points in open dissipative systems

TL;DR

This paper investigates two-body non-Hermitian physics in open dissipative systems, revealing how PT symmetry and interactions lead to exceptional points, with implications for probing non-Hermitian phenomena in many-body quantum systems.

Contribution

It demonstrates the emergence of two-body exceptional points in a minimal open quantum system using a Lindblad framework, linking few-body physics with non-Hermitian effects.

Findings

Identification of two-body PT transition points

Extraction of exceptional points from density matrix dynamics

Illustration of non-Hermitian physics in open many-body systems

Abstract

We study two-body non-Hermitian physics in the context of an open dissipative system depicted by the Lindblad master equation. Adopting a minimal lattice model of a handful of interacting fermions with single-particle dissipation, we show that the non-Hermitian effective Hamiltonian of the master equation gives rise to two-body scattering states with state- and interaction-dependent parity-time transition. The resulting two-body exceptional points can be extracted from the trace-preserving density-matrix dynamics of the same dissipative system with three atoms. Our results not only demonstrate the interplay of PT symmetry and interaction on the exact few-body level, but also serve as a minimal illustration on how key features of non-Hermitian few-body physics can be probed in an open dissipative many-body system.