SUPERFLUID PRECURSOR EFFECTS IN A MODEL OF HYBRIDIZED BOSONS AND FERMIONS

We examine how a superfluid state is approached in a system of localizedbosons (tightly bound electron pairs) in contact with a reservoir of itinerantfermions (electrons). Assuming spontaneous decay and recombination betweenthese two species, the initially localized states of the bosons change overinto free-particlelike propagating statesas the temperature is lowered and the superfluid transition at Tc is approached. Concomitantly a pseudogap opens up in the fermionic density of states which deepens with decreasing temperature. © 1995 The American Physical Society.