Optical clock and ultracold collisions with trapped strontium atoms

Abstract

With microkelvin neutral strontium atoms confined in an optical lattice, we have achieved a fractional resolution of better than 5 x 10−15 on the1 S o −3 P o doubly forbidden 87Sr clock transition at 698 nm. Measurements of the clock line shifts as a function of experimental parameters indicate that the fractional uncertainties due to systematic shifts could be reduced below 10−15. The ultrahigh spectral resolution permitted resolving the nuclear spin states of the clock transition at small magnetic fields, leading to measurements of the 3 P o magnetic moment and metastable lifetime. In addition, photoassociation spectroscopy was performed on the narrow 1 S o −3 P 1 transition of 88Sr, revealing the least-bound state, and showing promise for efficient optical tuning of the ground state scattering length and production of cold molecules.