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arXiv · 2407.00184

Anomalous high-density spin noise in a strongly interacting atomic vapor

J. Delpy·N. Fayard·F. Bretenaker·F. Goldfarb
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Abstract

Spin noise spectroscopy (SNS) has become a mainstream approach to probe the dynamics of a spin ensemble in and out of equilibrium. Current models describing spin noise in interacting samples are based on an effective single particle dynamics in a bath. Here, we report the observation of a strong interaction regime which significantly affects the spin dynamics. Performing SNS in a dense Rubidium vapor, we observe anomalous distortions of the usual spin noise spectra, which we attribute to resonant dipole-dipole interaction within the ensemble. As the density of the vapor increases, we observe a dramatic broadening of the usual resonances and the emergence of an unexpected extra low-frequency noise component. We use a simple microscopic two-body numerical model to reproduce and discuss these observations. Our results suggests that the spectra cannot be described by usual models of single-atom dynamics and arise from the evolution of interacting pair of atoms. This work opens the way to the study of many-body spin noise or higher order correlators in atomic vapors using SNS.

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J. Delpy, N. Fayard, F. Bretenaker, F. Goldfarb. 2024-06-28. Anomalous high-density spin noise in a strongly interacting atomic vapor. https://doi.org/10.1103/physrevresearch.7.013298

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