A vector plasma model for superdense matter and superluminal sound propagation

• Published in: Annals of physics Vol. 73; no. 1; pp. 19 - 48
• Main Authors: Kalman, G, Lai, S.T
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.01.1972
• ISSN: 0003-4916; 1096-035X
• DOI: 10.1016/0003-4916(72)90313-2

A model for an ultrahigh density system consisting of particles in a plasma-like state and interacting through a short range massive vector field is developed. Our main concern is to see how correlation effects modify the sound speed, the equation of state and the stability of the plasma state, and in particular whether superluminal sound propagation can occur. Correlation effects are treated by means of fluctuation-dissipation approach and also by ring approximation of Ursell-Mayer cluster expansion. In the domain of the validity of the plasma approximation correlation contributions cannot substantially modify the combined kinetic and Hartree terms and the sound speed is subluminal. For high densities and strong coupling leading outside the plasma domain correlations can dominate, possible phase transitions are present and the sound speed exceeds c, the velocity of light in vacuo. At very high densities the Hartree energy becomes overwhelming and the sound speed approaches c asymptotically again.