Chiral switching of many-body steady states in a dissipative Rydberg gas

TL;DR

This study experimentally demonstrates chiral switching between many-body steady states in a dissipative Rydberg vapor, highlighting the role of non-Hermitian physics and exceptional structures in open quantum systems.

Contribution

It reveals how non-Hermitian effects induce chiral switching in many-body steady states, a phenomenon not previously observed in dissipative Rydberg gases.

Findings

Chiral switching between steady states observed experimentally.

Exceptional points in parameter space cause bistability and state switching.

Switching dynamics are tunable via microwave dressing and temperature.

Abstract

Dissipative Rydberg gases are an outstanding platform for the investigation of many-body quantum open systems. Despite the wealth of existing studies, the non-equilibrium dynamics of dissipative Rydberg gases are rarely examined or harnessed from the perspective of non-Hermitian physics, which is but intrinsic to open systems. Here we report the experimental observation of a chiral switching between many-body steady states in a dissipative thermal Rydberg vapor, where the interplay of many-body effects and non-Hermiticity plays a key role. Specifically, as the parameters are adiabatically varied around a closed contour, depending on the chirality of the parameter modulation, the Rydberg vapor can change between two collective steady states with distinct Rydberg excitations and optical transmissions. Adopting a mean-field description, we reveal that both the existence of the bistable steady states and chiral dynamics derive from an exceptional structure in the parameter space, where multiple steady states of the many-body Liouvillian superoperator coalesce. We demonstrate that both the exceptional structure and the resulting state-switching dynamics are tunable through microwave dressing and temperature variations, confirming their reliance on the many-body dissipative nature of the Rydberg vapor.