LOWERING OF BOSON-FERMION SYSTEM ENERGY WITH A GAPPED COOPER RESONANT-PAIR DISPERSION RELATION

C. B. Dover

T. A. Mamedov, MANUEL DE LLANO

Applying two-time Green-function techniques to the Friedberg-T.D. Lee phenomenological Hamiltonian of a many-fermion system, it is shown that positive-energy resonant bosonic pairs associated with four-fermion excitations above the Fermi sea are energetically lower in a ground-state that is a mixture of two coexisting and dynamically interacting many-particle subsystems: a) unpaired fermions and b) composite bosons. It is argued that an interaction between free fermions and bosons excited above the Fermi sea in the mixture, namely, the continuous processes of pair-formation from, and disintegration into, two unpaired electrons, results in a substantially lowering the total system energy. The positive-energy composite bosons begin to appear incoherently below a depairing temperature T* as their coupling- and temperature-dependent number density gradually increases from zero. This leads quite naturally to the pseudogap phenomenon observed in high-Tccuprates.

J. Horne, Jorge A. Salas, Kálmán Varga

M. Moshińsky

IN THE PRESENT PAPER WE DISCUSS THE TRANSIENTS EFFECTS ASSOCIATED WITH THE DISPERSION BY AN IMPENETRABLE SPHERICAL POTENTIAL. THESES TRANSIENT EFFECTS ARE COMPARED WITH THOSE THAT APPEAR IN THE SINGLE LEVEL SCATTERING PROCESS, AND THEIR RELEVANCE TO THE TIME-ENERGY UNCERTAINTY RELATION IS ALSO DISCUSSED.

Dmitri V. Efremov, Luciano Viverit

We predict a p-wave Cooper pairing of the spin-polarized fermions in a binary fermion-boson mixture due to the exchange of density fluctuations of the bosonic medium. We then examine the dependence of the Cooper pairing temperature on the parameters of the system. We finally estimate the effect of combining the boson-induced interaction with other pairing mechanisms, e.g., the Kohn-Luttinger one, and find that the critical temperature of p-wave Cooper pairing can be realistic for experiment.

Mohit Randeria, Ji-Min Duan, Lih-Yir Shieh