Predictions of the thermodynamic conditions for phase transitions at high
baryon densities and large chemical potentials are currently uncertain and
largely phenomenological. Neutrino observations of core-collapse supernovae can
be used to constrain the situation. Recent simulations of stellar core collapse
that include a description of quark matter predict a sharp burst of anti \nu_e
several hundred milliseconds after the prompt \nu_e neutronization burst. We
study the observational signatures of that anti \nu_e burst at current neutrino
detectors - IceCube and Super-Kamiokande. For a Galactic core-collapse
supernova, we find that signatures of the QCD phase transition can be detected,
regardless of the neutrino oscillation scenario. The detection would constitute
strong evidence of a phase transition in the stellar core, with implications
for the equation of state at high matter density and the supernova explosion
mechanism.Comment: 6 pages, 4 figures; matches published version (1 additional figure,
added discussion of subsampling at IceCube). Accepted for publication in PR