Condensation of Hard-Core Pairs on a Lattice: A Model of the   Superconducting State in Cuprates
  Using the Monte Carlo technique we study the dependence of transition temperature, penetration depth and specific heat singularity on the pair concentration in the Bose Hubbard model. We observe remarkable agreement with the corresponding properties of cuprates. This points uniquely to Bose condensation of hard-core pairs on a lattice as the mechanism that drives the transition. 
Morten Holm Pedersen and Toni Schneider