Postmerger gravitational waves as a probe of a crossover QCD transition in binary neutron star mergers

Very high nuclear densities are attained in the core as neutron stars merge. During the collapse of the binary to form a black hole, it inevitably must pass through the transition from hadronic matter to a quark matter.  Hence,  gravitational waves emitted during this transition could be used to probe this phase of matter. In this talk, we analyze the evolution and gravitational wave emission from binary neutron star mergers using various  parameterizations of the Quark-Hadron Crossover (QHC19) equation of state which is motivated by non-perturbative QCD. We observe that if a crossover or weakly first-order transition occurs the postmerger gravitational wave emission is very sensitive to the high density quark-matter equation of state and can be used to probe properties of matter in the non-perturbative regime of QCD.