Rydberg Borromean Trimers

TL;DR

This paper introduces a novel type of ultralong-range triatomic molecule formed by a Rydberg atom and two ground-state atoms, which can exist as a Borromean system where no two-body subsystems are bound.

Contribution

It demonstrates the theoretical possibility of Borromean Rydberg trimers, expanding the understanding of ultralong-range molecular binding mechanisms.

Findings

Borromean Rydberg trimers can exist with attractive Rydberg-ground interactions.

Two-body subsystems are unbound, but the three-body system is bound.

This expands the class of ultralong-range molecules with unique binding properties.

Abstract

A Rydberg and a ground-state atom can form ultralong range diatomic molecules provided the interaction between the ground-state atom and the Rydberg electron is attractive [C. H. Greene, et al., Phys. Rev. Lett. 85, 2458 (2000)]. A repulsive interaction does not support bound states. However, as we will show, adding a second ground-state atom, a bound triatomic molecule becomes possible constituting a Borromean Rydberg system.