Pushing the uncertainty of a ytterbium optical lattice clock towards $10^{-17}$ fractional frequency

Ultracold alkaline-earth atoms confined in an optical lattice are well-suited as high-accuracy frequency standards. After a previous evaluation of systematic frequency shifts, our ytterbium optical lattice clock demonstrated $3.4\times10^{-16}$ fractional uncertainty. Here we summarize recent efforts which improve this uncertainty and the optical lattice clock overall, including precise characterization of the thermal radiation environment; dynamic blackbody radiation effects; and lattice-induced Stark shifts from the E1 polarizability, hyperpolarizability, and multipolar contributions.