Attractive Hubbard model with inhomogeneous interactions

I shall discuss the phase diagram of the attractive Hubbard model with spatially inhomogeneous interactions obtained using a single site dynamical mean field theory like approach. The model is characterized by three parameters: the interaction strength, the active fraction (fraction of sites with the attractive interaction), and electron filling. I show that in a parameter regime with intermediate values of interaction strength (compared to the bare bandwidth of the electrons), and intermediate values of the active fraction, ``non-BCS'' superconductivity is obtained. The results of this work are likely to be relevant to many systems with spatially inhomogeneous superconductivity such as strongly correlated oxides, systems with negative $U$ centers etc.