Testing relativity in the laboratory with optical lattice atomic clocks

The remarkable precision of optical atomic clocks offers sensitivity to new and exotic physics through tests of relativity, searches for dark matter, gravitational wave detection, and probes for beyond Standard Model?particles. While much of optical clock research has focused on improving absolute accuracy, many searches for new physics can be performed with relative comparisons between two clocks. To this end, we have recently realized a “multiplexed” strontium optical lattice clock consisting of two or more clocks in one vacuum chamber. This enables us to bypass many of the limitations present in typical atomic clock comparisons and to achieve new levels of precision.?

In this talk I will explain the motivation, concept, and operating principles of our multiplexed optical lattice clock. I will then present recent experimental results in which?we performed a novel, blinded, precision test of the gravitational redshift with an array of 5 evenly-spaced atomic ensembles spanning a total?height difference of 1?cm. I will present the error budget produced from our systematic evaluation, and the recently unblinded results of our first test. I will also discuss how these results can also be viewed as a proof-of-principle demonstration of relativistic geodesy at the sub-cm scale. Finally, I will discuss the outlook for future searches for new physics with our apparatus, including a novel direct test of the Einstein Equivalence Principle, and explorations of the interplay between general relativity and quantum mechanics.?