Renormalization group approach to the Fr\"ohlich polaron model: application to impurity-BEC problem

TL;DR

This paper introduces a renormalization group method to analyze Fröhlich polarons, specifically applied to impurity atoms in a Bose-Einstein condensate, showing excellent agreement with Monte Carlo results and exploring effective mass crossover.

Contribution

It develops a novel renormalization group approach for Fröhlich polarons and applies it to impurity-BEC systems, providing accurate energy and mass predictions.

Findings

Polaron energies match diagrammatic Monte Carlo results across interaction strengths.

Effective mass shows a smooth crossover from weak to strong coupling.

Potential experimental tests are discussed.

Abstract

We develop a renormalization group approach for analyzing Fr\"ohlich polarons and apply it to a problem of impurity atoms immersed in a Bose-Einstein condensate of ultra cold atoms. Polaron energies obtained by our method are in excellent agreement with recent diagrammatic Monte Carlo calculations for a wide range of interaction strengths. We calculate the effective mass of polarons and find a smooth crossover from weak to strong coupling regimes. Possible experimental tests of our results in current experiments with ultra cold atoms are discussed.