Polarizability of an optical lattice clock at 20 ppm

Optical lattice clocks, which are based on highly-forbidden ¹S₀ ↔ ³P₀ transitions of ultracold alkaline-earth atoms confined in standing-wave optical potentials [1], offer exquisite frequency stability and uncertainty. We leverage these advantages to determine the sensitivity of a ytterbium optical lattice clock to external electric fields at 20 part-per-million (ppm) accuracy [2]. We describe an electrode design compatible with various neutral optical atomic clocks and capable of absolute electric field generation at the ppm level. Importantly, the result bounds the uncertainty of the ytterbium clock frequency due to room-temperature blackbody radiation at the level of 3×10^-17.