Casimir--Polder induced Rydberg macrodimers

TL;DR

This paper theoretically explores how a conducting surface influences Rydberg atom pair potentials, revealing surface-induced bound states called Rydberg macrodimers with unique vibrational properties.

Contribution

It introduces the first theoretical analysis of Casimir--Polder effects on Rydberg macrodimers near a conducting surface, highlighting surface-induced potential wells and bound states.

Findings

Avoided crossings in pair potentials at small atom-surface distances

Existence of vibrational bound states (macrodimers) due to surface effects

Bound states with energies up to -68 MHz and micrometer-scale sizes

Abstract

We theoretically investigate Rydberg atom pair potentials of Rb atoms in front of a perfectly conducting plate. The pair potentials are perturbed by both the Casimir--Polder potential acting on a single atom and the scattering contribution to the interatomic interaction. In contrast to the pair potentials in free space, at atom-surface distances $d_s \lesssim 4\,\mu$m, avoided crossings appear. In the associated potential wells that are entirely due to dispersion interactions with the surface, there exist vibrational bound states, i.e. Rydberg macrodimers, with groundstate energies of up to $E = -68\,$MHz and radial expectation values of the order of several $\mu$m.