Detecting topological exceptional points in a parity-time symmetric system with cold atoms

TL;DR

This paper introduces a method to detect topological exceptional points in a parity-time symmetric system using cold atoms, enabling experimental exploration of non-Hermitian topological properties through atomic interferometry.

Contribution

It proposes a novel scheme to identify topological exceptional points in a four-level cold atomic system, linking non-Hermitian physics with experimental atomic interferometry.

Findings

Eigenstates can be swept through exceptional points via tunable parameters.

Non-trivial Berry phases can be measured using atomic interferometry.

The scheme is experimentally feasible for exploring non-Hermitian topological properties.

Abstract

We reveal a novel topological property of the exceptional points in a two-level parity-time symmetric system and then propose a scheme to detect the topological exceptional points in the system, which is embedded in a larger Hilbert space constructed by a four-level cold atomic system. We show that a tunable parameter in the presented system for simulating the non-Hermitian Hamiltonian can be tuned to swept the eigenstates through the exceptional points in parameter space. The non-trivial Berry phases of the eigenstates obtained in this loop from the exceptional points can be measured by the atomic interferometry. Since the proposed operations and detection are experimentally feasible, our scheme may pave a promising way to explore the novel properties of non-Hermitian systems.