Magnetometry

BEC

Spin-echo-based magnetometry with spinor Bose-Einstein condensates

In this work they have noticed that magnetic field created by ac line disrupts their experiments, by applying a magnetic field with an opposite phase they reduce the noise to 1 nT. As a magnetometer they achieved 12 pT/sqrt(Hz) with spatial resolution 100 um^2.

Technicalities. For the coils they use low ripple current source <2uA (Newport 505), they insert permalloy plates into the room walls. The BEC of ⁸⁷Rb is prepared in a crossed far-off resonant optical trap (FORT with w_axial=30 Hz, w_rad=100 Hz), 5*10³ atoms are prepared in F=2.