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The hadron-quark phase transition in quantum chromodynamics has been suggested as an alternative explosion mechanism for core-collapse supernovae. We study the impact of three different hadron-quark equations of state (EoS) with first-order (DD2F_SF, STOS-B145) and second-order (CMF) phase transitions on supernova dynamics by performing 97 simulations for solar- and zero-metallicity progenitors in the range of $14\tt {-}100\, \text{M}_\odot$. We find explosions only for two low-compactness models (14 and $16\, \text{M}_\odot$) with the DD2F_SF EoS, both with low explosion energies of ${\sim }10^{50}\, \mathrm{erg}$. These weak explosions are characterized by a neutrino signal with several minibursts in the explosion phase due to complex reverse shock dynamics, in addition to the typical second neutrino burst for phase-transition-driven explosions. The nucleosynthesis shows significant overproduction of nuclei such as 90Zr for the $14\hbox{-} \text{M}_\odot$ zero-metallicity model and 94Zr for the $16\hbox{-}\text{M}_\odot$ solar-metallicity model, but the overproduction factors are not large enough to place constraints on the occurrence of such explosions. Several other low-compactness models using the DD2F_SF EoS and two high-compactness models using the STOS EoS end up as failed explosions and emit a second neutrino burst. For the CMF EoS, the phase transition never leads to a second bounce and explosion. For all three EoS, inverted convection occurs deep in the core of the protocompact star due to anomalous behaviour of thermodynamic derivatives in the mixed phase, which heats the core to entropies up to 4kB/baryon and may have a distinctive gravitational-wave signature, also for a second-order phase transition.

 

In this work, we discuss the dense matter equation of state (EOS) for the extreme range of conditions encountered in neutron stars and their mergers. The calculation of the properties of such an EOS involves modeling different degrees of freedom (such as nuclei, nucleons, hyperons, and quarks), taking into account different symmetries, and including finite density and temperature effects in a thermodynamically consistent manner. We begin by addressing subnuclear matter consisting of nucleons and a small admixture of light nuclei in the context of the excluded volume approach. We then turn our attention to supranuclear homogeneous matter as described by the Chiral Mean Field (CMF) formalism. Finally, we present results from realistic neutron-star-merger simulations performed using the CMF model that predict signatures for deconfinement to quark matter in gravitational wave signals.