Electron-like and photon-like excitations in an ultracold Bose-Fermi atom mixture

TL;DR

This paper predicts the existence of electron-like and photon-like excitations in ultracold Bose-Fermi mixtures within optical lattices, proposing experimental methods to observe these quasiparticles through density response measurements.

Contribution

It introduces a theoretical framework for electron- and photon-like excitations in a Bose-Fermi Hubbard model and suggests experimental detection techniques.

Findings

Existence of electron- and photon-like excitations in the model

Stabilization of excitations in a Mott insulating phase

Proposal for observing excitations via time-of-flight experiments

Abstract

We show that the electron-like and photon-like excitations may exist in a three-dimensional Bose-Fermi Hubbard model describing ultracold Bose-Fermi atom mixtures in optical lattices. In a Mott insulating phase of the Bose atoms, these excitations are stabilized by an induced repulsive interaction between 'electrons' if the Fermi atoms are nearly half filling. We suggest to create 'external electric field' so that the electron-like excitation can be observed by measuring the linear density-density response of the 'electron' gas to the 'external field' in a time-of-flight experiment of the mixture. The Fermi surface of the 'electron' gas may also be expected to be observed in the time-of-flight.