Spin mixing in Cs ultralong-range Rydberg molecules: a case study

TL;DR

This paper models the vibrational spectra of Cs ultralong-range Rydberg molecules, incorporating full spin-resolved scattering and relativistic effects, achieving excellent agreement with experimental data.

Contribution

It introduces a comprehensive calculation including all relativistic effects and spin interactions in ultralong-range Rydberg molecules, a first in the field.

Findings

Accurate spectral line positions and profiles matching experimental data.

Determination of spin-dependent permanent electric dipole moments.

First calculation including all relativistic contributions in such molecules.

Abstract

We calculate vibrational spectra of ultralong-range Cs(32p) Rydberg molecules which form in an ultracold gas of Cs atoms. We account for the partial-wave scattering of the Rydberg electrons from the ground Cs perturber atoms by including the full set of spin-resolved ${}^{1,3}S_J$ and ${}^{1,3}P_J$ scattering phase shifts, and allow for the mixing of singlet (S=0) and triplet (S=1) spin states through Rydberg electron spin-orbit and ground electron hyperfine interactions. Excellent agreement with observed data in Sa{\ss}mannshausen et al. [Phys. Rev. Lett. 113, 133201(2015)] in line positions and profiles is obtained. We also determine the spin-dependent permanent electric dipole moments for these molecules. This is the first such calculation of ultralong-range Rydberg molecules in which all of the relativistic contributions are accounted for.