Ultracold long-range van der Waals Rydberg trimer

TL;DR

This paper predicts the formation of ultra-long-range van der Waals Rydberg trimers in dilute gases, revealing a new binding mechanism and providing estimates for their production rates and observability.

Contribution

It introduces a novel class of Rydberg molecules formed via van der Waals interactions, expanding the understanding of long-range molecular binding mechanisms.

Findings

Trimers have sizes between 5-500 nm.

Binding energies range from 2 MHz to 0.2 kHz.

Production rates are estimated at 10^{-13} to 10^{-11} cm^3s^{-1}.

Abstract

Rydberg molecules, Rydberg-atom or Rydberg-molecule, are an essential ingredient of cold molecular sciences. However, due to the richness of Rydberg-neutral interactions, new kinds of Rydberg molecules and binding mechanisms are still to be discovered. In this work, we predict the existence of ultra-long-range van der Waals trimers in dilute atom-gas mixtures. These are bound states of a Rydberg atom and a diatomic polar molecule mediated by the long-range van der Waals interaction. This new binding mechanism gives rise to trimers with sizes between 5-500~nm and binding energies between 2 MHz and 0.2 kHz depending on the atomic principal quantum number $n$ and orbital angular momentum $L$. We show that these molecules can be produced via two-photon photoassociation, with rates on the order of (10$^{-13}$ - 10$^{-11}$) cm$^{3}$s$^{-1}$ for temperatures in the range of (0.5 $\mu K$ - 10$\mu K$), and discuss the feasibility of observing trimer resonances.