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arXiv · 2009.02004

Strong zero-field F\"orster resonances in K-Rb Rydberg systems

J. Susanne Otto·Niels Kjærgaard·Amita B. Deb
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Abstract

We study resonant dipole-dipole coupling and the associated van der Waals energy shifts in Rydberg excited atomic rubidium and potassium and investigate F\"orster resonances between interspecies pair states. A comprehensive survey over experimentally accessible pair state combinations reveals multiple candidates with small F\"orster defects. We crucially identify the existence of an ultrastrong, "low" electric field K-Rb F\"orster resonance with a extremely large zero-field crossover distance exceeding 100 $\mu$m between the van der Waals regime and the resonant regime. This resonance allows for a strong interaction over a wide range of distances and by investigating its dependence on the strength and orientation of external fields we show this to be largely isotropic. As a result, the resonance offers a highly favorable setting for studying long-range resonant excitation transfer and entanglement generation between atomic ensembles in a flexible geometry. The two-species K-Rb system establishes a unique way of realizing a Rydberg single-photon optical transistor with a high-input photon rate and we specifically investigate an experimental scheme with two separate ensembles.

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J. Susanne Otto, Niels Kjærgaard, Amita B. Deb. 2020-09-04. Strong zero-field F\"orster resonances in K-Rb Rydberg systems. https://doi.org/10.1103/physrevresearch.2.033474

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