Polarons in Extremely Polarized Fermi Gases: The Strongly Interacting 6Li-40K Mixture

TL;DR

This paper investigates the properties of spin polarons in a strongly interacting, highly polarized mixture of lithium-6 and potassium-40 atoms, providing theoretical predictions for spectral functions, RF spectra, and relaxation dynamics.

Contribution

It offers a detailed analysis of spin polarons in a mass-imbalanced Fermi gas, including spectral properties and relaxation mechanisms, with predictions relevant for current experiments.

Findings

Determined the lifetime and effective mass of spin polarons.

Predicted RF spectra and momentum distributions for ${}^6$Li-${}^{40}$K mixtures.

Analyzed spin drag effects on polaron motion.

Abstract

We study the extremely polarized two-component Fermi gas with a mass imbalance in the strongly interacting regime. Specifically we focus on the experimentally available mixture of ${}^6$Li and ${}^{40}$K atoms. In this regime spin polarons, i.e., dressed minority atoms, form. We consider the spectral function for the minority atoms, from which the lifetime and the effective mass of the spin polaron can be determined. Moreover, we predict the radio-frequency (RF) spectrum and the momentum distribution for the spin polarons for experiments with ${}^6$Li and ${}^{40}$K atoms. Subsequently we study the relaxation of the motion of the spin polaron due to spin drag.