Cooper pairing at large N in a 2-dimensional model
  We study a 2-dimensional model of Fermi fields that is closely related to the Gross-Neveu model, and show that to leading order in 1/N a <psi-psi> condensate forms. This effect is independent of the chemical potential, a peculiarity that we expect to be specific to 2 dimensions. We also expect the condensate to be unstable against corrections at higher orders in 1/N. We compute the Green's functions associated with the composite psi-psi, and show that the Fermion acquires a Majorana mass proportional to the gap, and that a massless Goldstone pole appears. 
Alan Chodos, Hisakazu Minakata, and Fred Cooper