Direct comparison of two spin-squeezed optical clock ensembles at the 10^-17 level

State-of-the-art optical clocks are approaching the precision limit set by the inherent quantum projection noise of uncorrelated atoms. In this talk, we present a new optical clock system that integrates spin-squeezing into a strontium optical lattice clock to overcome this limitation. A high-finesse in-vacuum cavity enables the production of spin-squeezed states. A movable optical lattice bisecting the cavity allows for spin-squeezing and readout of sub-ensembles within the larger cloud of lattice-trapped strontium atoms. This new platform enables optical clock ensemble comparisons between individually spin-squeezed sub-ensembles. We will discuss the direct observation of spin-squeezed enhanced clock performance. We will comment on future improvements that will continue to advance entanglement-enhanced performance toward the state-of-the-art.