R. Haussmann, PROPERTIES OF A FERMI-LIQUID AT THE SUPERFLUID TRANSITION IN THE CROSSOVER REGION BETWEEN BCS SUPERCONDUCTIVITY AND BOSE-EINSTEIN CONDENSATION, Physical review. B, Condensed matter, 49(18), 1994, pp. 12975-12983
The self-consistent equations, which have been derived recently as a m
icroscopic model for the cross-over between BCS superconductivity and
Bose-Einstein condensation in a three-dimensional interacting Fermi sy
stem [R. Haussmann, Z. Phys. B 91, 291 (1993)], are solved numerically
by repeated Fourier transformation. We find a superfluid transition t
emperature T(c) which increases monotonically with increasing attracti
ve coupling strength. Furthermore, we determine the chemical potential
mu, the fermion distribution function n (k), and the complex effectiv
e mass 2m of the fermion pairs at T = T(c). The bound fermion pairs c
ause a power-law tail approximately k-4 in n (k) for large k and behav
e as short-living quasiparticles in the crossover region, which is ind
icated by a large imaginary part of 2m.