Measurement of the Electric Dipole Moment of ¹⁷¹Yb Atoms in an Optical Dipole Trap

The permanent electric dipole moment (EDM) of the ¹⁷¹Yb (I = 1/2) atom is measured with atoms held in an optical dipole trap (ODT). By enabling a cycling transition that is simultaneously spin-selective and spin-preserving, a QND measurement with a spin-state-detection efficiency of 50% is realized. A systematic effect due to parity mixing induced by a static E field is observed, and is suppressed by averaging between measurements with ODTs in opposite directions. The coherent spin precession time is found to be much longer than 300 s. The EDM is determined to be less than 1.5 x 10^-26 e·cm (95% C.L.). These measurement techniques can be adapted to search for the EDM of ²²⁵Ra.