Purcell modification of Auger and interatomic Coulombic decay

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 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.

Automated summary

This article provides analytical expressions for the rates of different relaxation processes in a two-atom system and compares these rates in free space to determine the dominant decay channel. The study shows that the ratio between the two dominating decay rates can be controlled by modifying the excitation propagation. The article also discusses the impact of a surface and a cavity on the decay rates.