Coherent Interaction of a Single Fermion with a Small Bosonic Field

TL;DR

This paper experimentally investigates a single fermion interacting with a small bosonic field in an optical lattice, revealing how fermions modify bosonic interactions and enabling inference of fermionic filling through phase dynamics.

Contribution

It provides the first detailed measurement of Bose-Fermi interaction strength and demonstrates how fermions influence bosonic interactions in a controlled optical lattice setting.

Findings

Measured absolute Bose-Fermi interaction strength as a function of scattering length.

Observed fermion-induced modifications of Bose-Bose interactions.

Inferred fermionic filling from interference in phase dynamics.

Abstract

We have experimentally studied few-body impurity systems consisting of a single fermionic atom and a small bosonic field on the sites of an optical lattice. Quantum phase revival spectroscopy has allowed us to accurately measure the absolute strength of Bose-Fermi interactions as a function of the interspecies scattering length. Furthermore, we observe the modification of Bose-Bose interactions that is induced by the interacting fermion. Because of an interference between Bose-Bose and Bose-Fermi phase dynamics, we can infer the mean fermionic filling of the mixture and quantify its increase (decrease) when the lattice is loaded with attractive (repulsive) interspecies interactions.