Engineering Quantum States of Matter for Atomic Clocks

Jun Ye

S. Bize

Martin M. Boyd, A. D. Ludlow, Sebastian Blatt +4 more

— Modern capabilities in quantum state engineering of ultracold matter and precise control of light fields now permit accurate control of interactions between matter and field to suit applications for precision tests of fundamental physics. We report on our recent development of a highly stable and accurate optical atomic clock based on ultracold neutral Sr atoms confined in an optical lattice. We discuss precision tools for the lattice clock, including stabilized lasers with sub-Hz linewidth, femtosecond-comb based technology allowing accurate clock comparison in both microwave and optical domains, and clock transfer over optical fibers. With microkelvin Sr atoms confined in an optical lattice that provide a zero differential a.c. Stark shift between two clock states, we achieve a resonance quality factor >2×10 on the S0 − P0 doubly forbidden Sr clock transition at 698 nm. High resolution spectroscopy of spin-polarized atoms is used for both high-performance clock operations and accurate atomic structure measurement. The overall systematic uncertainty of the clock has been evaluated at the 10−16 level, while the stability approaches low 10−15 at 1 s. These developments in precise engineering of lightatom interactions can be extended to the field of ultracold molecules, bringing new prospects for precision measurements, quantum control, and determinations of the constancy of the fundamental constants.

Christopher R. Monroe

Ross B. Hutson, Akihisa Goban, G. Edward Marti +3 more

We investigate the effects of stimulated scattering of optical lattice photons on atomic coherence times in a state-of-the art ^{87}Sr optical lattice clock. Such scattering processes are found to limit the achievable coherence times to less than 12 s (corresponding to a quality factor of 1×10^{16}), significantly shorter than the predicted 145(40) s lifetime of ^{87}Sr's excited clock state. We suggest that shallow, state-independent optical lattices with increased lattice constants can give rise to sufficiently small lattice photon scattering and motional dephasing rates as to enable coherence times on the order of the clock transition's natural lifetime. Not only should this scheme be compatible with the relatively high atomic density associated with Fermi-degenerate gases in three-dimensional optical lattices, but we anticipate that certain properties of various quantum states of matter-such as the localization of atoms in a Mott insulator-can be used to suppress dephasing due to tunneling.