Unusual temperature behavior of entropy of antiferromagnetic spin state in nuclear matter with effective finite range interaction

The unusual temperature behavior of the entropy of the antiferromagnetic (AFM) spin state in symmetric nuclear matter with the Gogny D1S interaction, being larger at low temperatures than the entropy of nonpolarized matter, is related to the dependence of the entropy on the effective masses of nucleons in a spin polarized state. The corresponding conditions for comparing the entropies of the AFM and nonpolarized states in terms of the effective masses are formulated, including low and high temperature limits. It is shown that the unexpected temperature behavior of the entropy of the AFM spin state at low temperatures is caused by the violation of the corresponding low temperature criterium.