A Relativistic Separable Potential to Describe Pairing in Nuclear Matter
  Using the Dirac-Hartree-Fock-Bogoliubov approximation to study nuclear pairing, we have found the short-range correlations of the Dirac $^1$S$_0$ pairing fields to be essentially identical to those of the two-nucleon virtual state at all values of the baryon density. We make use of this fact to develop a relativistic separable potential that correctly describes the pairing fields. 
B. Funke Haas, T. Frederico, B. V. Carlson and F. B. Guimar\~aes