QED calculation of the dipole polarizability of helium atom

摘要: The QED contribution to the dipole polarizability of $^{4}\mathrm{He}$ atom was computed, including effect finite nuclear mass. computationally most challenging second electric-field derivative Bethe logarithm obtained using two different methods: integral representation method Schwartz and sum-over-states approach Goldman Drake. results both calculations are consistent, although former turned out be much more accurate. value logarithm, equal 0.048 557 2(14) in atomic units, confirms small magnitude this quantity found only previous calculation [G. \L{}ach, B. Jeziorski, K. Szalewicz, Phys. Rev. Lett. 92, 233001 (2004)], but differs from it by about 5%. origin difference is explained. total correction order ${\ensuremath{\alpha}}^{3}$ fine-structure constant $\ensuremath{\alpha}$ amounts $30.6671(1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $0.1822\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ $0.011\phantom{\rule{0.16em}{0ex}}12(1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ for mass, with all values units. resulting theoretical molar helium-4 $0.517\phantom{\rule{0.16em}{0ex}}254\phantom{\rule{0.16em}{0ex}}08(5)\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{3}/\text{mol}$ error estimate dominated uncertainty corrections ${\ensuremath{\alpha}}^{4}$ higher. Our agreement an accurate than result $0.517\phantom{\rule{0.16em}{0ex}}254\phantom{\rule{0.16em}{0ex}}4(10)\phantom{\rule{0.28em}{0ex}}{\mathrm{cm}}^{3}/\text{mol}$ recent experimental determination [C. Gaiser Fellmuth, 120, 123203 (2018)].