Chiral Lagrangians at finite density

Abstract

The effective SU(2) chiral Lagrangian with external sources is given in the presence of non-vanishing nucleon densities by calculating the in-medium contributions of the chiral pion-nucleon Lagrangian. As a by product, a relativistic quantum field theory for Fermi many-particle systems at zero temperature is directly derived from relativistic quantum field theory with functional methods.

Comments: 6 Pages, 3 figures, REVTeX. Extended version. Explicit Feynman rules are given