PHENOMENOLOGICAL EQUATION OF STATE FOR QUARK MATTER

A model for quark matter, similar to the SLAC bag model, is used as a phenomenological basis in view of astrophysical illustrations. This model, although crude, is expected to be sufficient for this type of application where orders of magnitude only are required at this stage. This model consists of colored quarks interacting via scalar gluons (responsible for the confinement) and colored vector gluons. Although color-singlet states are assumed to be the states physically realized in nature, this assumption is not essential and can easily be relaxed. A covariant statistical-mechanical formalism based on the use of techniques similar to those of plasma physics is given. A Bogolubov-Born-Green-Kirkwood-Yvon hierarchy is obtained for the relevant statistical quantities (i.e., covariant Wigner functions, moments of the gluon fields, etc.). It is truncated at the third order (neglect of three-body correlations). The thermodynamical quantities are then evaluated and the resulting equation of state is applied to neutron stars. © 1979 The American Physical Society.