Enhancement of boson superfluidity in a one-dimensional Bose-Fermi mixture

TL;DR

This study investigates how boson-fermion interactions influence superfluidity in a one-dimensional mixture, revealing enhancement effects, phase transitions, and coexistence of orders, with implications for future experimental detection.

Contribution

It demonstrates that fermions can enhance boson superfluidity and induce phase transitions in a 1D Bose-Fermi mixture, a novel insight into their interplay.

Findings

Boson superfluidity is enhanced by fermions at weak coupling.

Fermion metal-insulator transition occurs without fermion-fermion interactions.

Boson superfluid and density wave orders can coexist in a Mott region.

Abstract

We examine the effect of boson-fermion interaction in a one-dimensional Bose-Fermi mixture by using the density matrix renormalization group method. We show that the boson superfluidity is enhanced by fermions for a weak boson-fermion coupling at an approximate integer boson filling factor (e.g., $0.935\le \rho_b \le 1.0$), and this enhancement is produced both in a fermion metallic state and in a fermion insulating state. A metal-insulator phase transition of fermions induced by boson-fermion interaction is observed even though there is no fermion-fermion interaction in the parent Hamiltonian. Furthermore, we find that the boson superfluid order and density wave order can coexist in a deep fermion Mott region. All these features could be measured in future experiments and open up the possibility of detecting the new physical effect in the Bose-Fermi mixture.