Spontaneous emission and atomic line shift in causal perturbation theory

TL;DR

This paper uses causal perturbation theory to derive atomic spontaneous emission rates and line shifts, revealing that the cutoff frequency for the line shift depends on atomic mass, not traditional scales.

Contribution

It introduces a causal perturbation theory approach to atomic emission, avoiding divergences and providing new insights into the cutoff frequency determination.

Findings

Confirmed atomic decay rate matches previous results.

Line shift cutoff frequency depends on atomic mass.

Method avoids divergent integrals in quantum electrodynamics.

Abstract

We derive spontaneous emission rate and line shift for two-level atoms coupled to the radiation field using causal perturbation theory. In this approach, employing the theory of distribution splitting prevents the occurrence of divergent integrals. Our method confirms the result for atomic decay rate but suggests that the cutoff frequency for the atomic line shift is determined by the atomic mass, rather than Bohr radius or electron mass.