Blackbody-radiation shift in aCa+43ion optical frequency standard

Abstract

Motivated by the prospect of an optical frequency standard based on $^{43}\mathrm{Ca}^{+}$, we calculate the blackbody-radiation (BBR) shift of the $4{s}_{1∕2}\ensuremath{-}3{d}_{5∕2}$ clock transition, which is a major component of the uncertainty budget. The calculations are based on the relativistic all-order single-double method where all single and double excitations of the Dirac-Fock wave function are included to all orders of perturbation theory. Additional calculations are conducted for the dominant contributions in order to evaluate some omitted high-order corrections and estimate the uncertainties of the final results. The BBR shift obtained for this transition is $0.38(1)\phantom{\rule{0.3em}{0ex}}\mathrm{Hz}$. The tensor polarizability of the $3{d}_{5∕2}$ level is also calculated and its uncertainty is evaluated as well. Our results are compared with other calculations.