Equilibrium and Linear Response of a Classical Scalar Plasma

Abstract

The properties of a classical many-particle system interacting through a scalar field (a scalar plasma) are studied. A relativistic Hartree approximation is applied to equilibrium to evaluate thermodynamic characteristics such as the energy, entropy, and equation of state. A gas-liquid phase transition appears at moderate densities. There is no collapse for an attractive interaction: The system can accomodate any density. Stability against small perturbation and the behavior of collective excitations are analyzed through the linear-response function.