Polaronic mass renormalization of impurities in BEC: correlated Gaussian wavefunction approach

TL;DR

This paper introduces a variational Gaussian wavefunction approach to accurately describe polaron energies and effective masses in Bose-Einstein condensates, revealing significant mass renormalization and measurable correlation patterns.

Contribution

The authors develop a new correlated Gaussian wavefunction method that improves polaron energy predictions and uncovers novel correlation signatures in ultracold atomic systems.

Findings

Polaron energies match Monte Carlo results across interaction strengths.

Effective masses are substantially larger than mean-field predictions.

Predicts measurable correlation patterns in time-of-flight experiments.

Abstract

We propose a class of variational Gaussian wavefunctions to describe Fr\"ohlich polarons at finite momenta. Our wavefunctions give polaron energies that are in excellent agreement with the existing Monte Carlo results for a broad range of interactions. We calculate the effective mass of polarons and find smooth crossover between weak and intermediate impurity-bosons coupling. Effective masses that we obtain are considerably larger than those predicted by the mean-field method. A novel prediction based on our variational wavefunctions is a special pattern of correlations between host atoms that can be measured in time-of-flight experiments. We discuss atomic mixtures in systems of ultracold atoms in which our results can be tested with current experimental technology.