Theory of normal state single particle and transport properties

In the framework of a scenario consisting of a mixture of itinerant electro ns and localized bipolarons, hybridized with each other via a charge exchan ge term, we discuss the evolution of certain physical features of the pseud ogap phase as the temperature decreases from T* to T-c. This evolution can be characterized by the presence of purely diffusive electron-pairs just be low T*, their becoming itinerant below a certain temperature T-B* and their ultimate condensation into a superconducting state at T-c. An onset of a D rude component in the optical conductivity and imperfect Meissner screening in the temperature interval [T-c, T-B*]are manifestations of that.