A simplified method for calculating the ac Stark shift of hyperfine levels

摘要

The ac Stark shift of hyperfine levels of neutral atoms can be calculatedusing the third order perturbation theory(TOPT), where the third ordercorrections are quadratic in the atom-photon interaction and linear in thehyperfine interaction. In this paper, we use Green's function to derive the$E^{[2+\epsilon]}$ method which can give close values to those of TOPT for thedifferential light shift between two hyperfine levels. It comes with a simpleform and easy incorporation of theoretical and experimental atomic structuredata. Furthermore, we analyze the order of approximation and give the conditionunder which $E^{[2+\epsilon]}$ method is valid.