γ-ray bursts and the QCD phase diagram

Abstract

The quantum chromodynamics phase diagram shows the phase transitions that can take place in matter at different temperatures and densities. In this work we discuss the possibility that \ensuremath{\gamma}-ray bursts might result from a phase change in the interior of a neutron star and calculate the energy released in the conversion of a metastable star into a stable star. We consider several different initial and several different final configurations. Initial metastable stars are taken as hadronic, hybrid, and quark stars with unpaired quarks; possible stable stars are hybrid and quark stars, taken both with unpaired and paired phases to study the deconfinement phase transition and normal quark matter--superconducting quark matter phase transition within a large number of relativistic models used to describe compact stars. The models used for the hadron matter are the nonlinear Walecka model and the quark-meson coupling model with and without hyperons. For the quark matter we have used the MIT bag model, the bag model with paired quarks to which we refer as the color-flavor-locked phase model, and the Nambu--Jona-Lasinio model. Within this mechanism we obtain energies of the order of ${10}^{50}\ensuremath{-}{10}^{53}$ erg, accounting for both long and short \ensuremath{\gamma}-ray bursts.