The QCD phase transition and supernova core collapse

Abstract

We examine the implications for stellar core collapse of a phase transition occurring at densities of a few times nuclear matter density. We use a schematic equation of state motivated by the Skyrme model low-energy approximation to QCD, which contains a phase transition corresponding to the conversion of bulk nuclear matter to a chirally symmetric quark-gluon phase. We analyze the stability of the core against gravitational collapse with respect to the amount of gravitational binding energy released and the kinematic energy of the shock. We show that a first-order phase transition actually gives rise to two shocks which quickly coalesce. More importantly, we show that there are significant differences in the evolution of cores with or without first- or second-order phase transitions which may eventually lead to observational signatures in the neutrino signal.