UAM, Madrid

Generalized BCS Ansatz for Pairing Correlations in Superconducting grains

The natural degrees of freedom associated with finite systems are fully taken into account. As an example, the formalism is applied to the reduced pairing Hamiltonian where we reproduce the exact solutions in the weak, crossover and strong pairing regimes. The physical insight of the Ansatz and its numerical simplicity make this theory an excellent tool to study pairing correlations in more complex and realistic systems than the one discussed here.