Sign-Alternating Interaction Mediated by Strongly-Correlated Lattice Bosons

Understand

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.