PROPERTIES OF A FERMI-LIQUID AT THE SUPERFLUID TRANSITION IN THE CROSSOVER REGION BETWEEN BCS SUPERCONDUCTIVITY AND BOSE-EINSTEIN CONDENSATION

The self-consistent equations, which have been derived recently as a microscopic model for the cross-over between BCS superconductivity and Bose-Einstein condensation in a three-dimensional interacting Fermi system [R. Haussmann, Z. Phys. B 91, 291 (1993)], are solved numerically by repeated Fourier transformation. We find a superfluid transition temperature T(c) which increases monotonically with increasing attractive coupling strength. Furthermore, we determine the chemical potential mu, the fermion distribution function n (k), and the complex effective mass 2m* of the fermion pairs at T = T(c). The bound fermion pairs cause a power-law tail approximately k-4 in n (k) for large k and behave as short-living quasiparticles in the crossover region, which is indicated by a large imaginary part of 2m*.