Non-linear density scaling of spin noise reveals atomic correlations in warm vapors
Abstract
We experimentally demonstrate a non-linear dependence of the spin noise variance on atomic density in a warm alkali vapor. Implementing high-bandwidth spin noise spectroscopy (SNS) near the D2 transition of rubidium, a quadratic spin noise contribution is shown to arise at high densities, in contrast with the linear dependence valid in non-interacting ensembles. This non-linear scaling is shown to crucially depend on the residual optical excitation of the vapor by the probe beam, suggesting it stems from atomic cross-correlations due to resonant dipole-dipole interaction (DDI) in the vapor. We support this claim by introducing an additional experimental protocol to quench the ddi, resulting in a suppression of both the quadratic scaling of the spin variance and the distortions of the spin noise spectrum induced by the interaction. These results extend the applications of SNS to the characterization of many-body correlations in complex quantum systems.
Versions
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BibTeX
@misc{delpy2026nonlinear,
title = {{Non-linear density scaling of spin noise reveals atomic correlations in warm vapors}},
author = {Joseph Delpy and Elwyn Cardoz and Adwaith KV and Nikos Fayard and Nadia Belabas and Fabien bretenaker and Fabienne Goldfarb},
howpublished = {arXiv},
year = {2026},
month = may,
doi = {10.48550/arxiv.2605.31262},
eprint = {2605.31262},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.31262},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Non-linear density scaling of spin noise reveals atomic correlations in warm vapors
AU - Joseph Delpy
AU - Elwyn Cardoz
AU - Adwaith KV
AU - Nikos Fayard
AU - Nadia Belabas
AU - Fabien bretenaker
AU - Fabienne Goldfarb
PY - 2026
DA - 2026/05/29
PB - arXiv
DO - 10.48550/arxiv.2605.31262
UR - https://arxiv.org/abs/2605.31262
AB - We experimentally demonstrate a non-linear dependence of the spin noise variance on atomic density in a warm alkali vapor. Implementing high-bandwidth spin noise spectroscopy (SNS) near the D2 transition of rubidium, a quadratic spin noise contribution is shown to arise at high densities, in contrast with the linear dependence valid in non-interacting ensembles. This non-linear scaling is shown to crucially depend on the residual optical excitation of the vapor by the probe beam, suggesting it stems from atomic cross-correlations due to resonant dipole-dipole interaction (DDI) in the vapor. We support this claim by introducing an additional experimental protocol to quench the ddi, resulting in a suppression of both the quadratic scaling of the spin variance and the distortions of the spin noise spectrum induced by the interaction. These results extend the applications of SNS to the characterization of many-body correlations in complex quantum systems.
ER -