Lattice Light Shift Evaluations in a Dual-Ensemble Yb Optical Lattice Clock.

In state-of-the-art optical lattice clocks, beyond-electric-dipole polarizability terms lead to a breakdown of magic wavelength trapping. In this Letter, we report a novel approach to evaluate lattice light shifts, specifically addressing recent discrepancies in the atomic multipolarizability term between experimental techniques and theoretical calculations. We combine imaging and multi-ensemble techniques to evaluate lattice light shift atomic coefficients, leveraging comparisons in a dual-ensemble lattice clock to rapidly evaluate differential frequency shifts.

Deployment of a transportable Yb optical lattice clock.

We report on the first deployment of a ytterbium (Yb) transportable optical lattice clock (TOLC), commercially shipping the clock 3000 km from Boulder, Colorado, to Washington DC. The system, composed of a rigidly mounted optical reference cavity, an atomic physics package, and an optical frequency comb, fully realizes an independent frequency standard for comparisons in the optical and microwave domains. The shipped Yb TOLC was fully operational within 2 days of arrival, enabling frequency comparison with a rubidium (Rb) fountain at the United States Naval Observatory (USNO).

Evaluation of Lattice Light Shift at Low 10^{-19} Uncertainty for a Shallow Lattice Sr Optical Clock.

A Wannier-Stark optical lattice clock has demonstrated unprecedented measurement precision for optical atomic clocks. We present a systematic evaluation of the lattice light shift, a necessary next step for establishing this system as an accurate atomic clock. With precise control of the atomic motional states in the lattice, we report accurate measurements of the multipolar and the hyperpolar contributions and the operational lattice light shift with a fractional frequency uncertainty of 3.

Resolving the gravitational redshift across a millimetre-scale atomic sample.

Einstein's theory of general relativity states that clocks at different gravitational potentials tick at different rates relative to lab coordinates-an effect known as the gravitational redshift. As fundamental probes of space and time, atomic clocks have long served to test this prediction at distance scales from 30 centimetres to thousands of kilometres. Ultimately, clocks will enable the study of the union of general relativity and quantum mechanics once they become sensitive to the finite wavefunction of quantum objects oscillating in curved space-time.