Fermi surface anomaly and depletion of the Fermi sea in the relativistic Brueckner-Hartree-Fock approximation.

Abstract

The Fermi surface anomaly consists in a variation, localized in the vicinity of the Fermi energy, of the energy derivative of the real part of the nuclear mean field. A quantitative analysis of this anomaly is performed in the framework of the relativistic Brueckner-Hartree-Fock approximation to the mean field in symmetric nuclear matter. The investigation is based on dispersion relations that connect the imaginary to the real part of the Lorentz components of the mean field; its main input is the imaginary part of the relativistic mean field recently calculated by ter Haar and Malfliet from a one-boson-exchange nucleon-nucleon interaction. It is found that the Fermi surface anomaly is very nearly the same as in the nonrelativistic Brueckner-Hartree-Fock approximation. However, the physical origin of the anomaly is quite different in the two cases. Relatedly, the predicted depletion of the Fermi sea is much smaller in the relativistic than in the nonrelativistic description. As a consequence, the rearrangement and renormalization corrections are much smaller in the relativistic than in the nonrelativistic case.