Performance and Deployment of a Portable Ytterbium Lattice Clock

Optical lattice clocks (OLCs) are currently the most precise timekeeping apparatuses; their ability to measure fractional frequency changes at the 10^-18 level with just a few hours of averaging time allows them to detect gravitational redshift due to variation in Earth’s geopotential at the 1cm level, comparable with current geodetic leveling techniques. In order to prepare for relativistic geodesy measurements, we have evaluated systematic shifts on our portable ¹⁷¹Yb OLC, constraining the fractional frequency uncertainty due to systematic shifts to the 3.7 10^-18 level. To validate our error budget, we have compared our clock locally to the stationary Yb lab clocks at NIST over a period of several months, observing consistency at the <5 10^-18 level between three Yb clocks. In preparation for deployment to a mountaintop for relativistic geodesy measurements, we have deployed to the CU campus and the DOC facility at Table Mountain, comparing back to the stationary NIST clocks over phase noise compensated fiber and with a free-space optical time transfer scheme, respectively. Finally, we outline a plan for a relativistic geodesy measurement at Mt Blue Sky by comparing our portable Yb clock to our lab Yb clocks via a combination of fiber and free-space optical frequency transfer.