Purcell modification of Auger and interatomic Coulombic decay

TL;DR

This paper develops a quantum optical framework to analyze and control competing decay processes like Auger and interatomic Coulombic decay in two-atom systems, demonstrating how macroscopic environments influence decay rates.

Contribution

It provides analytical expressions for decay rates including environmental effects and shows how to manipulate decay channels using the Purcell effect.

Findings

Decay rates depend on atomic properties and environment.

Macroscopic bodies can significantly alter decay channel dominance.

Application to HeNe-dimer illustrates control over decay processes.

Abstract

An excited two-atom system can decay via different competing relaxation processes. If the excess energy is sufficiently high the system may not only relax via spontaneous emission but can also undergo interatomic Coulombic decay (ICD) or even Auger decay. We provide analytical expressions for the rates by including them into the same quantum optical framework on the basis of macroscopic quantum electrodynamics. By comparing the rates in free space we derive the atomic properties determining which decay channel dominates the relaxation. We show that by modifying the excitation propagation of the respective process via macroscopic bodies, in the spirit of the Purcell effect, one can control the ratio between the two dominating decay rates. We can relate the magnitude of the effect to characteristic length scales of each process, analyse the impact of a simple close-by surface onto a general two-atom system in detail and discuss the effect of a cavity onto the decay rates. We finally apply our theory to the example of a doubly excited HeNe-dimer.