Quasi-forbidden 2-body F\"orster resonances in cold Cs Rydberg gas

TL;DR

This paper reveals a large number of quasi-forbidden F"orster resonances in cold Cs Rydberg atoms, significantly expanding the understanding of energy transfer pathways and their potential applications in quantum systems.

Contribution

It introduces a graphical method to identify all possible quasi-forbidden resonances, highlighting their strong interactions at low electric fields.

Findings

Large number of quasi-forbidden resonances observed

Significant energy transfer efficiency at low electric fields

Graphical method for resonance identification developed

Abstract

Cold Rydberg atoms are known to display dipole-dipole interaction allowed resonances, also called F\"orster resonances, which lead to an efficient energy transfer when the proper electric field is used. This electric field also enables resonances which do not respect the dipole-dipole selection rules under zero field. A few of these quasi-forbidden resonances have been observed but they are often overlooked. Here we show that in cold $^{133}$Cs atoms there is a large number of these resonances that display a significant transfer efficiency due to their strong interactions, even at low electric field. We also develop a graphical method enabling to find all possible resonances simultaneously. The resulting dramatic increase in the total number of addressable resonant energy transfers at different electric fields could have implications in the search for few-body interactions or macro-molecules built from Rydberg atoms.