Two-photon spontaneous emission of an atom in a cosmic string background

TL;DR

This paper investigates how a cosmic string background influences the spontaneous emission processes of an atom, revealing significant effects on emission rates and spectral distributions due to the cosmic string's spacetime geometry.

Contribution

It provides the first analysis of both one-photon and two-photon spontaneous emission rates and spectral distributions of an atom near a cosmic string, highlighting the impact of the string's geometry.

Findings

One-photon emission rate depends on distance and deficit angle.

Two-photon spectral distribution is significantly altered by the cosmic string.

Emission properties are sensitive to the cosmic string's spacetime geometry.

Abstract

It is well known that the vicinities of an atomic system may substantially affect its radiative properties. In this work, we consider the influence of a cosmic string background in the spontaneous emission of an excited atom. We start by computing the one-photon spontaneous emission rate of a quantum emitter, which is a narrow band process, and then we analyze the more complex case of the two-photon spontaneous emission, which is a broad band and much richer phenomenon. In the former case, we analyze not only the behavior of the decay rate with the distance from the atom to the string, but also with the deficit angle associated with the cosmic string metric. In the latter case, we show that the spectral distribution of the emitted photons is substantially affected by the cosmic string background.