Landau-Ginzburg method applied to finite fermion systems: Pairing in   Nuclei
  Given the spectrum of a Hamiltonian, a methodology is developed which employs the Landau-Ginsburg method for characterizing phase transitions in infinite systems to identify phase transition remnants in finite fermion systems. As a first application of our appproach we discuss pairing in finite nuclei. 
M. K. G. Kruse, H. G. Miller, A. R. Plastino, A. Plastino and S.   Fujita