Optical Lattice Clock with Spin-polarized 87Sr Atoms

We present a new evaluation of an 87Sr optical lattice clock using spin polarized atoms. The frequency of the 1S0→3P0 clock transition is found to be 429 228 004 229 873.6 Hz with a fractional uncertainty of 2.6×10-15, a value that is comparable to the frequency difference between the various primary standards throughout the world. This measurement is in excellent agreement with a previous one of similar accuracy [Phys. Rev. Lett. 98, 083002 (2007)].