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arXiv · 2608.15130

Stochastic Liouville-transport theory of light-atom interaction noise in thermal atomic vapors

Shaoxin Yuan·Bin Wu·Mingyong Jing·Chaoyang Hu·Yan Peng·Tingting Li·Xingya Li·Wenguang Yang·Junyao Xie·Zongkai Liu·Hao Zhang·Linjie Zhang·Liantuan Xiao·Suotang Jia
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Abstract

Atom-light interaction noise can limit thermal-vapor sensing. Existing theories often treat internal-state dynamics, finite-mode atomic motion, and stochastic renewal separately, obscuring their coupled contributions to measured noise. We develop a general stochastic Liouville-transport theory, tested against polarization-resolved resonant Cs D$_2$ spectra. Joint experiment-theory analysis identifies atom-light noise below approximately 100 kHz as transit-dominated. Ballistic motion through the finite Gaussian mode modulates both the coupling-weighted effective atom number and trajectory-dependent Rabi coupling, producing predominantly common-mode noise. Boundary renewal introduces atoms with independently sampled ground-state sublevels, generating differential population fluctuations with opposite effects on the circular channels. Under an applied longitudinal magnetic field, experiment and theory show the same qualitative nonmonotonic change in common-mode suppression, supporting Zeeman redistribution of the channel responses. The framework can analyze noise in other thermal-atom sensors, including Rydberg-atom electric-field measurements.

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Shaoxin Yuan, Bin Wu, Mingyong Jing, Chaoyang Hu, Yan Peng, Tingting Li, Xingya Li, Wenguang Yang, Junyao Xie, Zongkai Liu, Hao Zhang, Linjie Zhang, Liantuan Xiao, Suotang Jia. 2026-08-15. Stochastic Liouville-transport theory of light-atom interaction noise in thermal atomic vapors. https://arxiv.org/abs/2608.15130

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