Seminarium Optyczne

This study explores the nonlinear non-Hermitian physics in dissipative Rydberg gases, focusing on Liouvillian exceptional structures and stochastic resonance for sensing applications. Using a thermal Rydberg vapor as a many-body open system, we experimentally demonstrate chiral switching between two collective steady states with distinct excitation and transmission properties. This dynamics is governed by a Liouvillian exceptional structure, where two exceptional lines merge at a higher-order exceptional point, underpinning both the bistability and the chirality of the state transfer under parameter modulation. Such a non-Hermitian perspective offers a paradigm for controlling many-body states via exceptional points. Furthermore, leveraging the strong nonlinearity and intrinsic noise in the Rydberg ensemble, we implement stochastic resonance to detect weak microwave fields. By harnessing noise, the sensor achieves a significant signal-to-noise ratio enhancement, surpassing heterodyne atomic detection sensitivity by 6.6 dB. These findings establish dissipative Rydberg gases as a versatile platform for investigating non-Hermitian physics and advancing noise-enhanced quantum sensing technologies.