Sign-Alternating Interaction Mediated by Strongly-Correlated Lattice Bosons

TL;DR

This paper uncovers a universal mechanism where strongly correlated lattice bosons induce sign-alternating inter-site interactions, significantly altering the phase diagram of a two-component Bose-Hubbard model and enabling novel quantum phases.

Contribution

It introduces a new mechanism for sign-alternating interactions mediated by strongly correlated bosons and demonstrates its impact on the phase diagram of the Bose-Hubbard model.

Findings

Discovery of sign-alternating mediated interactions.

Modification of the phase diagram with a solid+superfluid phase.

Identification of potential new quantum phases.

Abstract

We reveal a generic mechanism of generating sign-alternating inter-site interactions mediated by strongly correlated lattice bosons. The ground state phase diagram of the two-component hard-core Bose-Hubbard model on a square lattice at half-integer filling factor for each component, obtained by worm algorithm Monte Carlo simulations, is strongly modified by these interactions and features the solid+superfluid phase for strong anisotropy between the hopping amplitudes. The new phase is a direct consequence of the effective nearest-neighbor repulsion between "heavy" atoms mediated by the "light" superfluid component. Due to their sign-alternating character, mediated interactions lead to a rich variety of yet to be discovered quantum phases. quantum phases.