The remarkable precision of optical atomic clocks enables new applications and can provide sensitivity to novel and exotic physics. In this talk I will explain the motivation and operating principles of a “multiplexed" strontium optical lattice clock, which consists of two or more atomic ensembles of trapped, ultra-cold strontium in one vacuum chamber. This miniature clock network enables us to bypass the primary limitations to standard comparisons between atomic clocks and thereby achieve new levels of precision.
I will present experimental results in which we make use of multiple atomic ensembles to perform enhanced phase estimation and demonstrate a reduced absolute instability of an optical lattice clock. I will also briefly present the results of a blinded, laboratory-based precision test of the gravitational redshift at the millimeter to centimeter scale that takes advantage of synchronous differential comparisons to enhance the sensitivity of the measurement while mitigating common-mode systematics. I will then present out progress towards a second-generation experimental apparatus that will enable precision measurements of the gravitational redshift at the meter-scale on a table top. And finally, I will discuss recent measurements demonstrating how we can use our apparatus to study and leverage the level structure of strontium in order to extend the achievable coherent clock interrogation time.