Quark flavors in hot and dense holographic QCD: setup and comparison to data

Abstract: We establish a flavor dependent holographic framework for hot and dense QCD. To this end, we generalize a class of bottom-up holographic models for QCD in the Veneziano limit (V-QCD) by incorporating explicit flavor dependence. Specifically, we develop a $2+1$ flavor model characterized by two massless light quarks and a massive strange quark. Including the non-zero quark mass modifies the tachyon dependence of the model action, which yields a good agreement with the lattice data for thermodynamics in QCD in the low baryon number density and high temperature limit. We compare the model with various hadron resonance gas models at low temperature. We also compute the equation of state (EOS) at high density and low temperatures and found a smooth matching of this EOS with the nuclear matter EOS, suggesting significantly lower latent heat of the nuclear to quark matter transition than in earlier version of the V-QCD model. We observe that the smooth matching with the nuclear theory EOS is only applicable to a subset of potentials; furthermore, constraining the predictions of the model by limiting the potential parameters. We also identify the relevant fixed points of the model, particularly AdS$_2$ and AdS$_5$ fixed points.