Mass-energy and anomalous friction in quantum optics

TL;DR

This paper introduces a relativistic correction to the multipolar atom-light Hamiltonian, clarifying how internal mass-energy changes affect atomic motion and resolving apparent friction phenomena in quantum optics.

Contribution

It provides a low-order relativistic correction to the multipolar Hamiltonian, improving the understanding of atom-light interactions and internal energy changes.

Findings

Relativistic correction modifies atom-light interaction models.

Internal mass-energy changes influence atomic momentum.

Clarifies the nature of anomalous friction in quantum optics.

Abstract

The usual multipolar Hamiltonian for atom-light interaction features a non-relativistic moving atom interacting with electromagnetic fields which inherently follow Lorentzian symmetry. This combination can lead to situations where atoms appear to experience a friction force, when in fact they only change their internal mass-energy due to the emission or absorption of a photon. Unfortunately the simple Galilean description of the atom's motion is not sufficient to distinguish between a change in momentum due to acceleration and a change in momentum due to a change in internal mass-energy. In this work we show how a low-order relativistic correction can be included in the multipolar atom-light Hamiltonian. We also give examples how this affects the most basic mechanical interactions between atoms and photons.