Sensitive BEC magnetometry with optimized probing

Abstract

An improved spatial magnetometer using a spinor Bose-Einstein condensate of ${}^{87}$Rb atoms is realized utilizing newly developed two-polarization phase contrast imaging. The optical shot noise is suppressed by carefully choosing the probe parameters. We attain a dc-magnetic field sensitivity of 7.7 $pT/\sqrt{\mathrm{Hz}}$ over a measurement area of 28 $\mu {\mathrm{m}}^2$. The attained sensitivity per unit area is superior to that for other modern low-frequency magnetometers with micrometer-order spatial resolution. This result is a promising step for realizing quantum-enhanced magnetometry surpassing classical methods.

12 pages, 3 figures, submitted to Physical Review Letters