Dipole-Dipole coupled double Rydberg molecules

TL;DR

This paper demonstrates how dipole-dipole interactions between Rydberg atoms can create long-range molecules with tunable properties influenced by external electric fields, revealing new molecular binding mechanisms.

Contribution

It introduces a novel mechanism for Rydberg molecule formation via resonant dipole-dipole interactions and explores how external fields control their potential landscapes.

Findings

Long-range molecules form from dipole-dipole interactions.

External electric fields tune the well depth and position.

Different geometries lead to localized and donut-shaped potentials.

Abstract

We show that the dipole-dipole interaction between two Rydberg atoms can give rise to long range molecules. The binding potential arises from two states that converge to different separated atom asymptotes. These states interact weakly at large distances, but start to repel each other strongly as the van der Waals interaction turns into a resonant dipole-dipole interaction with decreasing separation between the atoms. This mechanism leads to the formation of an attractive well for one of the potentials. If the two separated atom asymptotes come from the small Stark splitting of an atomic Rydberg level, which lifts the Zeeman degeneracy, the depth of the well and the location of its minimum are controlled by the external electric field. We discuss two different geometries that result in a localized and a donut shaped potential, respectively.