Screening of oscillating external electric field in atoms

TL;DR

This paper investigates how noble-gas atoms screen oscillating external electric fields using many-body calculations, revealing complex frequency-dependent behaviors and implications for nuclear electric dipole moment studies.

Contribution

It provides a detailed analysis of the frequency-dependent screening of oscillating electric fields in noble gases, highlighting effects near atomic resonances and at zero frequency.

Findings

Screening vanishes at the nucleus at zero frequency.

Field magnitude can exceed external field at certain points.

Resonance effects can enhance the field near atomic transitions.

Abstract

We study the screening of a homogeneous oscillating external electric field $E_0$ in noble-gas atoms using atomic many-body calculations. At zero frequency of the oscillations ($\omega=0$) the screened field $E(r)$ vanishes at the nucleus, $E(0)=0$. However, the profile of the field $E(r)$ is complicated, with the magnitude of the field exceeding the external field $E_0$ at certain points. For $\omega >0$ the field $E(r,\omega)$ strongly depends on $\omega$ and at some points may exceed the external field $E_0$ many times. The field at the nucleus is not totally screened and grows with $\omega$ faster than $\omega^2$. It can even be enhanced when $\omega$ comes close to resonance with a frequency of an atomic transition. This field interacts with CP-violating nuclear electric dipole moments creating new opportunities for studying them. The screening of the external field by atomic electrons may strongly suppress (or enhance near an atomic resonance) the low energy nuclear electric dipole transitions.