Magnetic susceptibility of superdense systems and thermodynamics of strong interactions

Abstract

Magnetic susceptibility of a system of neutrons at very high densities is calculated. The strong interactions are included by specifying the hadron resonance spectrum and using the thermodynamic theory of Hagedorn and others. A knowledge of the relation between average spin and mass is also necessary. For one such plausible relation the susceptibility is shown to increase with an increase in density contrary to the decrease for a noninteracting fermion system. The increase is due to the very slow increase in Fermi energy because of the production of higher-mass particles, and to the increase in spin of such particles.