# Covariant thermodynamics and 'realistic' Friedmann model

Authors
Publication Date
Aug 01, 1995
Source
INSPIRE-HEP
We discuss a cosmological Friedmann model modified by inclusion of off-shell matter which has an equation of state $p,\rho \propto T~5,$ $p=1/4\rho .$ Such matter is shown to have energy density comparable with that of non-interacting radiation at temperatures of the order of the Hagedorn temperature, $\sim 10~{12}$ K, indicating the possibility of a phase transition. It is argued that the $T~5$-phase, or an admixture, lies below the high-temperature $T~4$-phase.