Measurement and extinction of vector light shifts using interferometry   of spinor condensates
  We use differential Ramsey interferometry of ultracold atoms to characterize the vector light shift (VLS) from a far-off resonance optical dipole trap at $\lambda = 1064\,\mathrm{nm}$. The VLS manifests as a `fictitious' magnetic field, which we perceive as a change in the Larmor frequency of two spinor condensates exposed to different intensities of elliptically polarized light. We use our measurement scheme to diagnose the light-induced magnetic field and suppress it to $2.1(8)\times10^{-4}$ of its maximum value, by making the trapping light linearly polarized with a quarter-wave plate in each beam. Our sensitive measurement of the VLS-induced field demonstrates high-precision, in-vacuo interferometric polarimetry of dipole trapping light and can be adapted to measure vector shifts from other lasers, advancing the application of optically trapped atoms to precision metrology. 
A. A. Wood, L. D. Turner, R. P. Anderson
quant-ph cond-mat.quant-gas physics.atom-ph