Superconductivity in a Binary Boson-Fermion Mixture with Weak Interaction

A concept describing the origin of the pseudogap phase of high-T _c superconducting cuprates is discussed. Based on the idea about electron-composite boson mixture, existing below some value T _p in cuprates, first, an analytical expression for T _p is obtained. It is shown that T _p depends on interaction parameter responsible for two electron-composite boson transformation, as well on the boson formation energy. Second, the composite boson condensation temperature T _c, determined as a one below which the density of condensed bosons just ceases to be zero, is found. The reason why the behaviors of T _p and T _c in dependence on the interaction parameter may be so different is addressed.