Negative spontaneous emission by a moving two-level atom

TL;DR

This paper explores how a moving two-level atom interacting with a plasmonic slab's near field can exhibit negative spontaneous emission, leading to population inversion under certain conditions, with implications for quantum friction.

Contribution

It introduces a theoretical framework showing negative spontaneous emission in a moving atom near a plasmonic surface, linking quantum effects to classical problems.

Findings

Negative spontaneous emission occurs at high velocities and small separations.

Population inversion is achieved due to the atom's interaction with the moving near field.

The theory connects quantum friction phenomena with classical analogs.

Abstract

In this paper we investigate how the dynamics of a two-level atom is affected by its interaction with the quantized near field of a plasmonic slab in relative motion. We demonstrate that for small separation distances and a relative velocity greater than a certain threshold, this interaction can lead to a population inversion, such that the probability of the excited state exceeds the probability of the ground state, corresponding to a negative spontaneous emission rate. It is shown that the developed theory is intimately related to a classical problem. The problem of quantum friction is analyzed and the differences with respect to the corresponding classical effect are highlighted.