Środowiskowe Seminarium z Informacji i Technologii Kwantowych
sala 0.06, ul. Pasteura 5
2023-12-14 (11:15) 
Kostas Mouloudakis (ICFO Barcelona)
Probing spin fluctuations in dense alkali-metal media
Spin-based devices, like optically pumped magnetometers (OPMs), constitute a great example of quantum sensing by offering a testbed for both applied and fundamental investigations. OPMs utilizing the spin-degrees of freedom of high-density alkali-metal vapors are currently at the forefront of applied magnetometry, yet involving intriguing quantum effects at the atom-light interface.
In this talk, we report on the spontaneous spin fluctuations of the collective spin of such atomic ensembles, that ultimately limit the performance of OPMs. We will give a brief introduction to spin-noise spectroscopy, the field studying these fluctuations, and we will discuss recent advances both in single- and dual-species atomic ensembles. In particular, we will discuss spin noise in the spin-exchange-relaxation-free (SERF) regime, a parameter-regime where some of the most sensitive magnetometer operate. We do that by considering a mean-field spin evolution augmented by stochastic Ornstein-Uhlenbeck dynamics. We will derive the full two-time spin covariance matrix and the observable noise spectra in Faraday rotation experiments and we will compare the model against precision measurements in a 87Rb, as well as in a mixture of 87Rb-133Cs vapors.
References
[1] Phys. Rev. A 106, 023112 (2022)
[2] Phys. Rev. A 108, 052822 (2023)
[3] arXiv: 2307. 16869v1 (2023)
In this talk, we report on the spontaneous spin fluctuations of the collective spin of such atomic ensembles, that ultimately limit the performance of OPMs. We will give a brief introduction to spin-noise spectroscopy, the field studying these fluctuations, and we will discuss recent advances both in single- and dual-species atomic ensembles. In particular, we will discuss spin noise in the spin-exchange-relaxation-free (SERF) regime, a parameter-regime where some of the most sensitive magnetometer operate. We do that by considering a mean-field spin evolution augmented by stochastic Ornstein-Uhlenbeck dynamics. We will derive the full two-time spin covariance matrix and the observable noise spectra in Faraday rotation experiments and we will compare the model against precision measurements in a 87Rb, as well as in a mixture of 87Rb-133Cs vapors.
References
[1] Phys. Rev. A 106, 023112 (2022)
[2] Phys. Rev. A 108, 052822 (2023)
[3] arXiv: 2307. 16869v1 (2023)