High accuracy correction of blackbody radiation shift in an optical lattice clock

Abstract

We have determined the frequency shift that blackbody radiation is inducing on the \(5s^2\) \(^1\)S\(_0\) -- \(5s5p\) \(^3\)P\(_0\) clock transition in strontium. Previously its uncertainty limited the uncertainty of strontium lattice clocks to \(1\times10^{-16}\). Now the uncertainty associated to the black body radiation shift correction translates to \(5\times 10^{-18}\) relative frequency uncertainty at room temperature. Our evaluation is based on a measurement of the differential dc-polarizability of the two clock states and on a modeling of the dynamic contribution using this value and experimental data for other atomic properties.