Single-domain Bose condensate magnetometer achieves energy resolution per bandwidth below ℏ.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35131850.
- Also identified by DOI 10.1073/pnas.2115339119 and PMC identifier 8833174.
- Licence recorded as CC BY-NC-ND.
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Abstract
We present a magnetic sensor with energy resolution per bandwidth [Formula: see text] We show how a <sup>87</sup>Rb single-domain spinor Bose-Einstein condensate, detected by nondestructive Faraday rotation probing, achieves single-shot low-frequency magnetic sensitivity of 72(8) fT measuring a volume [Formula: see text] for 3.5 s, and thus, [Formula: see text] We measure experimentally the condensate volume, spin coherence time, and readout noise and use phase space methods, backed by three-dimensional mean-field simulations, to compute the spin noise. Contributions to the spin noise include one-body and three-body losses and shearing of the projection noise distribution, due to competition of ferromagnetic contact interactions and quadratic Zeeman shifts. Nonetheless, the fully coherent nature of the single-domain, ultracold two-body interactions allows the system to escape the coherence vs. density trade-off that imposes an energy resolution limit on traditional spin precession sensors. We predict that other Bose-condensed alkalis, especially the antiferromagnetic <sup>23</sup>Na, can further improve the energy resolution of this method.