Precision Measurements with an 87Sr Optical Lattice Clock

The uncertainty of our $^{87}$Sr optical lattice clock operating on the ultranarrow $^1S_0$-$^3P_0$ transition has recently reached 1.5$\times 10^{-16}$. We will report our latest work in further reducing this uncertainty. One of the largest frequency shifts---a density shift---has now been characterized at the $5 \times 10^{-17}$ level. An understanding of the measurement-induced Fermionic interactions at ultracold temperatures has allowed us to zero the density shift altogether by operating the clock near a 50\% excitation fraction. Furthermore, we report advancements in characterizing blackbody radiation-induced clock shifts. Recent progress toward high-fidelity manipulations of the long-lived nuclear- and electronic-spin states in alkaline earth atoms, a capability that will be useful for neutral-atom-based quantum information processing, will also be presented.