Measuring Gravitational Redshift at the Centimeter Scale with a Multiplexed Strontium Optical Lattice Clock

Optical lattice clocks are amongst the most accurate and precise devices ever built. Their remarkable performance is giving rise to a number of novel applications. In this poster, we will present a "multiplexed" strontium optical lattice clock we have contructed that enables high precision differential measurements between ensembles of ultracold strontium atoms confined in spatially resolved regions of an optical lattice. We will discuss our use of synchronized Ramsey interrogation between multiple ensembles. By making use of a clock transition with reduced magnetic sensitivity, we observe atom-atom coherence times exceeding 10 seconds and measure differential stabilities below 3×10−17/√τ . We will also present preliminary results in which we measure gravitational redshifts between ensembles separated by height difference of 1 cm or less, and will discuss our evaluation of the systematic uncertainty in these measurements. Finally, we will discuss some exciting future prospects for the "multiplexed" clock, such as utilizing Rydberg-dressed spin-squeezing to further enhanced the differential stability, isotope-shift measurements, and tests of relativity with accelerated clocks.