  We explore explosions of massive stars, which are triggered via the
quark-hadron phase transition during the early post bounce phase of
core-collapse supernovae. We construct a quark equation of state, based on the
bag model for strange quark matter. The transition between the hadronic and the
quark phases is constructed applying Gibbs conditions. The resulting
quark-hadron hybrid equations of state are used in core-collapse supernova
simulations, based on general relativistic radiation hydrodynamics and three
flavor Boltzmann neutrino transport in spherical symmetry. The formation of a
mixed phase reduces the adiabatic index, which induces the gravitational
collapse of the central protoneutron star. The collapse halts in the pure quark
phase, where the adiabatic index increases. A strong accretion shock forms,
which propagates towards the protoneutron star surface. Due to the density
decrease of several orders of magnitude, the accretion shock turns into a
dynamic shock with matter outflow. This moment defines the onset of the
explosion in supernova models that allow for a quark-hadron phase transition,
where otherwise no explosions could be obtained. The shock propagation across
the neutrinospheres releases a burst of neutrinos. This serves as a strong
observable identification for the structural reconfiguration of the stellar
core. The ejected matter expands on a short timescale and remains neutron-rich.
These conditions might be suitable for the production of heavy elements via the
r-process. The neutron-rich material is followed by proton-rich neutrino-driven
ejecta in the later cooling phase of the protoneutron star where the vp-process
might occur.
