Nonconservative dipole forces in a two-atom system with one atom excited

TL;DR

This paper calculates nonconservative electric dipole forces between two atoms, one excited, revealing components orthogonal to the interatomic axis and potential experimental accessibility despite their small magnitude.

Contribution

It introduces the concept of nonconservative dipole forces in a two-atom system with one excited atom, highlighting their unique properties and potential observability.

Findings

Nonconservative forces have orthogonal components to the interatomic axis.

These forces are smaller than van-der-Waals but potentially measurable.

Nonreciprocal forces lead to a net force on the atom pair.

Abstract

We compute the nonconservative electric dipole forces between two atoms, one of which is initially excited. These forces derive from the time variation of the longitudinal electromagnetic momentum. In contrast to the conservative van-der-Waals forces, the nonconservative forces posses components orthogonal to the interatomic axis. Thus, despite being several orders of magnitude smaller than van-der-Waals', they might be accessible experimentally for the case of two identical atoms. In addition, as with the van-der-Waals forces, the nonconservative forces present nonreciprocal constituents which result in a net force on the two-atom system. We offer an estimate of the spatial displacement caused by the nonconservative forces on a binary system of Hydrogen atoms.