Atomic many-body effects and Lamb shifts in alkali metals

TL;DR

This paper develops a method to accurately calculate quantum electrodynamics radiative corrections, including many-body effects, for alkali metals across a wide range of nuclear charges, improving the precision of Lamb shift predictions.

Contribution

The paper introduces a detailed approach combining the Flambaum-Ginges radiative potential with many-body effects to accurately compute QED corrections in heavy alkali atoms.

Findings

Radiative potential method achieves 1% accuracy compared to rigorous QED calculations.

Many-body effects significantly increase the size of self-energy shifts, especially for d waves.

Self-energy shifts for d waves in heavy alkali atoms are comparable to s-wave shifts.

Abstract

We present a detailed study of the Flambaum-Ginges radiative potential method which enables the accurate inclusion of quantum electrodynamics (QED) radiative corrections in a simple manner in atoms, ions, and molecules over the range 10<=Z<=120, where Z is the nuclear charge. Calculations are performed for binding energy shifts to the lowest valence s, p, and d waves over the series of alkali atoms Na to E119. The high accuracy of the radiative potential method is demonstrated by comparison with rigorous QED calculations in frozen atomic potentials, with deviations on the level of 1%. The many-body effects of core relaxation and second- and higher-order perturbation theory on the interaction of the valence electron with the core are calculated. The inclusion of many-body effects tends to increase the size of the shifts, with the enhancement particularly significant for d waves; for K to E119, the self-energy shifts for d waves are only an order of magnitude smaller than the s-wave shifts. It is shown that account of many-body effects is essential for an accurate description of the Lamb shift.