Bosonic Kondo-Hubbard model

TL;DR

This paper investigates the phase diagram and magnetic properties of the bosonic Kondo-Hubbard model in two dimensions using quantum Monte Carlo simulations, revealing continuous phase transitions and ferromagnetic phases.

Contribution

It provides the first detailed quantum Monte Carlo analysis of the bosonic Kondo-Hubbard model, challenging mean-field predictions and exploring magnetic phases.

Findings

Transition from paramagnetic Mott insulator to ferromagnetic superfluid is continuous.

Both Mott insulator and superfluid phases are ferromagnetic at double occupation.

Quantum Monte Carlo simulations reveal magnetic properties not predicted by mean-field theory.

Abstract

We study, using quantum Monte-Carlo simulations, the bosonic Kondo-Hubbard model in a two dimensional square lattice. We explore the phase diagram and analyse the mobility of particles and magnetic properties. At unit filling, the transition from a paramagnetic Mott insulator to a ferromagnetic superfluid appears continuous, contrary to what was predicted with mean field. For double occupation per site, both the Mott insulating and superfluid phases are ferromagnetic and the transition is still continuous. Multiband tight binding Hamiltonians can be realized in optical lattice experiments, which offer not only the possibility of tuning the different energy scales over wide ranges, but also the option of loading the system with either fermionic or bosonic atoms.