Theory of excitation of Rydberg polarons in an atomic quantum gas

TL;DR

This paper develops a quantum many-body framework to analyze Rydberg polarons in a Bose gas, extending existing methods to finite mass cases and comparing with experimental data.

Contribution

It introduces a comprehensive many-body theory for Rydberg polarons, including finite mass effects, and connects theoretical predictions with experimental observations.

Findings

The theory accurately describes the excitation spectrum of Rydberg polarons.

Mean-field and classical approximations are derived and compared.

Experimental data from strontium Bose-Einstein condensates are explained by the model.

Abstract

We present a quantum many-body description of the excitation spectrum of Rydberg polarons in a Bose gas. The many-body Hamiltonian is solved with functional determinant theory, and we extend this technique to describe Rydberg polarons of finite mass. Mean-field and classical descriptions of the spectrum are derived as approximations of the many-body theory. The various approaches are applied to experimental observations of polarons created by excitation of Rydberg atoms in a strontium Bose-Einstein condensate.