Sign-alternating interaction mediated by strongly correlated lattice bosons

We reveal a generic mechanism of generating sign-alternating intersite 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 (SF) phase for strong asymmetry between the hopping amplitudes. The new phase is a direct consequence of the effective nearest-neighbor repulsion between \u27heavy\u27 atoms mediated by the \u27light\u27 SF component. Due to their sign-alternating character, mediated interactions lead to a rich variety of yet to be discovered quantum phases