Ultralong-Range Rydberg Molecules in a Divalent-Atomic System

TL;DR

This paper reports the creation and detection of ultralong-range Sr₂ Rydberg molecules in a cold atomic gas, using two-photon excitation and theoretical modeling to understand their binding energies.

Contribution

It introduces the formation of ultralong-range Sr₂ molecules with a divalent-atomic system, combining experimental creation with theoretical analysis.

Findings

Molecules created in a trapped ultracold gas using two-photon excitation.

Binding energies fit with Fermi pseudopotential and scattering lengths.

Observation of molecules for principal quantum numbers n=29 to 36.

Abstract

We report the creation of ultralong-range Sr$_2$ molecules comprising one ground-state $5s^2$ $^1S_0$ atom and one atom in a $5sns$ $^3S_1$ Rydberg state for $n$ ranging from 29 to 36. Molecules are created in a trapped ultracold atomic gas using two-photon excitation near resonant with the $5s5p$ $^3P_1$ intermediate state, and their formation is detected through ground-state atom loss from the trap. The observed molecular binding energies are fit with the aid of first-order perturbation theory that utilizes a Fermi pseudopotential with effective $s$-wave and $p$-wave scattering lengths to describe the interaction between an excited Rydberg electron and a ground-state Sr atom.