2024/02/16 by K. Mouloudakis, V. Koutrouli, Mouloudakis, K. +7
Biochemistry, Genetics and Molecular Biology · Engineering · Physics and Astronomy · #Atomic and Subatomic Physics Research #FOS: Physical sciences #Geomagnetism and Paleomagnetism Studies #Magnetic Field Sensors Techniques #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2402.10746
openalex publication_date 2024/02/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Present protocols for obtaining the ultimate magnetic sensitivity of optically pumped magnetometers (OPMs) utilizing alkali-metal ensembles rely on uncorrelated atoms in stretched states. A new approach for calculating the spin projection noise (SPN)-limited signal to noise ratio (SNR) and the magnetic sensitivity of OPMs is proposed. Our model is based solely on the mean-field density matrix dynamics and in contrast to previous models, it applies to both low and high field regimes, it takes into account the degree of spin polarization, the intra- and interhyperfine correlations, the decoherence processes, the atom-light coupling and the effects of the spin dynamics on the spin-noise spectra. Fine tuning of the probe frequency allow us to explore different hyperfine states and ground-state correlations. Especially in the spin-exchange-relaxation-free (SERF) regime, alongside the magnetic resonance narrowing and the increased number density, hallmarks of SERF magnetometers, we report on a new SERF feature; the reduction of spin-projection noise at the spin precession frequency as a consequence of strongly-correlated hyperfine spins that attenuate and redistribute SPN when properly probed.