Dipole-dipole-coupled double-Rydberg molecules

摘要

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