Bipolaronic superconductivity with dispersive phonons

We use the newly developed Monte Carlo method based on the path-integral formulation of the particle sector in combination with the real space diagrammatics of the phonon sector to study the effects of a finite dispersion of optical phonon mode on BEC of bipolarons in the bond model. For dispersionless phonons, this model was recently shown to give rise to small-size, light-mass bipolarons that undergo a superfluid transition at high values of Tc. For dispersive phonons,Tc stays relatively high over a significantly broader range of the coupling strength and even keeps increases in the deep adiabatic regime. This means more possibilities and less need for fine-tuning in the search for new materials with high superconducting temperatures.