Bound states, Cooper pairing, and Bose condensation in two dimensions

Abstract

For a dilute gas of fermions interacting via an arbitrary pair potential in d=2 dimensions, we show that the many-body ground state is unstable to s-wave pairing at T=0 if and only if a two-body bound state exists. We further obtain, within a variational pairing Ansatz, a smooth crossover from a Cooper-paired state (ξ0kf≫1) to a Bose condensed state of tightly bound pairs (ξ0kf≪1). We briefly discuss non–s-wave superconductors. Insofar as this model is appli- cable to the high-Tc materials, they are in the interesting regime with the coherence length ξ0 comparable to the interparticle spacing Kf−1.

Source-reported materials — not catalogue approval

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