Time delay of mean-field interaction in thermal Rydberg atomic gases

• Published in: Optics express Vol. 33; no. 10; p. 20829
• Main Authors: Wang, Yuzhuo, Gao, Tianxiong, Niu, Yufan, Hu, Ying, Zhang, Linjie, Jia, Suotang, Jing, Mingyong, Xiao, Yanhong
• Format: Journal Article
• Language: English
• Published: United States 19.05.2025
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.557186

Mean-field theory is commonly employed to study nonequilibrium dynamics in hot Rydberg atomic ensembles, but the fundamental mechanism behind the generation of the mean-field interactions remains poorly understood. In this work, we experimentally observe a time-delay effect in the buildup of mean-field interaction, which reveals the key role of collision ionization. We analyze the relevant collision channels and propose a microscopic mechanism that quantitatively explains the hysteresis window observed in optical bistability. Then, using square-wave modulation spectroscopy (SMS) to monitor the growth of the mean-field interaction, we experimentally demonstrate a delay in its dynamical buildup following the initial Rydberg excitation. Finally, we demonstrate how this delay effect may help understand the recently observed self-sustained oscillations in a thermal Rydberg gas. Our findings provide compelling evidence for the contribution of ionization processes in the nonequilibrium dynamics of thermal Rydberg gases, a system of growing interest for quantum sensing and quantum information science.