Observation of the Borromean three-body F\"orster resonances for three interacting Rb Rydberg atoms

TL;DR

This paper reports the first experimental observation of three-body F"orster resonances in a few Rb Rydberg atoms, demonstrating their presence for three or more atoms and potential applications in quantum control.

Contribution

First experimental detection of three-body F"orster resonances in Rb Rydberg atoms, confirming their existence beyond large ensembles and enabling new quantum interaction control.

Findings

Three-body F"orster resonances observed for N=3-5 atoms.

No three-body resonance signature for exactly two atoms.

Resonances can be used to control three-body interactions in quantum systems.

Abstract

Three-body F\"orster resonances at long-range interactions of Rydberg atoms were first predicted and observed in Cs Rydberg atoms by R.Faoro et al., Nature Comm. 6, 8173 (2015). In these resonances, one of the atoms carries away an energy excess preventing the two-body resonance, leading thus to a Borromean type of F\"orster energy transfer. But they were in fact observed as the average signal for the large number of atoms $N\gg1$. In this Letter we report on the first experimental observation of the three-body F\"orster resonances ${\rm 3}\times nP_{3/2} (|{\rm M}|)\to nS_{1/2} +(n+1)S_{1/2} +nP_{3/2} (|{\rm M}^{*} |)$ in a few Rb Rydberg atoms with $n=36, 37$. We have found here clear evidence that there is no signature of the three-body F\"orster resonance for exactly two interacting Rydberg atoms, while it is present for $N=3-5$ atoms. This demonstrates the assumption that three-body resonances can generalize to any Rydberg atom. As such resonance represents an effective three-body operator, it can be used to directly control the three-body interactions in quantum simulations and quantum information processing with Rydberg atoms.