# Single-Particle properties of a strongly-interacting Bose-Fermi mixture with mass and population imbalance

## TL;DR

This paper explores the effects of mass and population imbalance on the single-particle spectral properties of strongly interacting Bose-Fermi mixtures, revealing persistent spectral anomalies that can be observed via photoemission spectroscopy.

## Contribution

It extends previous balanced mixture studies to imbalanced systems, demonstrating that spectral anomalies remain observable under realistic imbalance conditions.

## Key findings

- Multiple peak structures in spectral weight persist in imbalanced mixtures.
- Spectral anomalies are detectable via photoemission spectrum.
- Results are relevant for real trapped Bose-Fermi mixtures with imbalance.

## Abstract

We theoretically investigate strong-coupling properties of a Bose-Fermi mixture. In the mass- and population-balanced case, two of the authors have shown that a strong hetero-pairing interaction in this mixture brings about coupling phenomena between Fermi atomic excitations and Bose atomic and composite molecular excitations, that appear as an anomalous multiple peak structure in the single-particle spectral weight (SW). [D. Kharga, {\it et. al.}, J. Phys. Soc. Jpn. {\bf 86}, 084301 (2017)]. In this paper, extending this previous work, we show that, although these many-body phenomena are sensitive to mass and population imbalances between the Bose and Fermi components, SW still exhibits the multiple peak structure in a moderately mass-imbalanced $^{87}$Rb-$^{40}$K and $^{23}$Na-$^{40}$K mixtures. We also point out that the photoemission spectrum is a useful quantity to observe this spectral anomaly. Since a real trapped Bose-Fermi mixture is usually accompanied by mass and (local) population imbalance, our results would contribute to the study of a strongly interacting Bose-Fermi mixture, under realistic imbalanced conditions.