Differential clock comparisons with a multiplexed optical lattice clock

Optical lattice clocks are amongst the most accurate and precise devices ever built. Their remarkable stability is now giving rise to a number of novel applications. In this talk, we will report on recent results in which we have implemented a “multiplexed” strontium optical lattice clock, which enables high precision differential frequency comparisons between ensembles of ultracold strontium atoms confined in a mutually shared lattice. We will first discuss our approach to performing synchronous Ramsey interrogation between multiple ensembles, enabling observation of 26 s atom-atom coherence times, and reaching relative instability below 1×10^-17/√τ at 1 s and long-term instability at 10^-20 level simultaneously for up to 10 unique pairwise clock comparisons. Second, we will discuss our progress in measuring the gravitational redshift between ensembles separated in height by less than 1 cm. Finally, we will discuss some exciting prospects for the “multiplexed” clock, such as studying Rydberg-dressed spin-squeezing for quantum enhanced metrology, isotope-shift measurements to search for new forces, and precision tests of fundamental physics.