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VLS induced effective magnetic field gradient

(Top) The scalar light shift from a focused laser beam (orange) creates a spin-independent trapping potential, proportional to the (inverted) intensity profile. Gravity acts to tilt and shallow the potential (blue), with a trap minimum offset from the intensity maximum.
(Bottom ) A BEC (circle) trapped in this potential experiences a greater intensity variation than at the beam centre, accentuating the gradient of the vector light shift.