Radiative Corrections to the Polarizability of Helium

The complete ${\alpha }^3$ QED correction to the helium atom polarizability is computed assuming an infinite nuclear mass and found to be equal to 0.000 030 666(3) a.u., with the contribution from the electric-field dependence of the Bethe logarithm amounting to 0.000 000 193(2) a.u. After including the ${\alpha }^2$ and ${\alpha }^3$ corrections for the nuclear recoil and the leading part of the ${\alpha }^4$ QED correction, we find that the molar polarizability of ${}^4\mathrm{He}$ is $0.51725419(9)(4){\mathrm{cm}}^3/\mathrm{mol}$. The first of the two error bounds is dominated by the uncertainty of ${\alpha }^4$ and higher-order QED corrections and the second reflects the uncertainty of the Avogadro constant.