Emergent Fermi sea in a system of interacting bosons

TL;DR

This paper predicts that a Fermi sea can emerge in a two-dimensional system of interacting bosons under a synthetic magnetic field, revealing a novel state where bosons form fermionic bound states.

Contribution

It introduces the concept of a Fermi sea arising in bosonic systems due to interactions and magnetic fields, supported by exact diagonalization and variational methods.

Findings

Fermi sea likely forms at filling factor of unity

Fermions are bound states of bosons and vortices

State observed in two-component bosons with contact interactions

Abstract

An understanding of the possible ways in which interactions can produce fundamentally new emergent many-body states is a central problem of condensed matter physics. We ask if a Fermi sea can arise in a system of bosons subject to contact interaction. Based on exact diagonalization studies and variational wave functions, we predict that such a state is likely to occur when a system of two-component bosons in two dimensions, interacting via a species independent contact interaction, is exposed to a synthetic magnetic field of strength that corresponds to a filling factor of unity. The fermions forming the SU(2) singlet Fermi sea are bound states of bosons and quantized vortices, formed as a result of the repulsive interaction between bosons in the lowest Landau level.