@article{1889,
  abstract     = {We study translation-invariant quasi-free states for a system of fermions with two-particle interactions. The associated energy functional is similar to the BCS functional but also includes direct and exchange energies. We show that for suitable short-range interactions, these latter terms only lead to a renormalization of the chemical potential, with the usual properties of the BCS functional left unchanged. Our analysis thus represents a rigorous justification of part of the BCS approximation. We give bounds on the critical temperature below which the system displays superfluidity.},
  author       = {Bräunlich, Gerhard and Hainzl, Christian and Seiringer, Robert},
  journal      = {Reviews in Mathematical Physics},
  number       = {7},
  publisher    = {World Scientific Publishing},
  title        = {{Translation-invariant quasi-free states for fermionic systems and the BCS approximation}},
  doi          = {10.1142/S0129055X14500123},
  volume       = {26},
  year         = {2014},
}