QCD Equation of State from Black Hole and Hadronic Physics

We present a new equation of state for hot and dense matter with a broad coverage in density and temperature, obtained by merging a Hadron Gas Model with van der Waals interactions with a deconfined medium described through holography. A family of 5-dimensional holographic black holes, constrained to mimic the lattice QCD equation of state at zero density, is used to investigate the temperature and baryon chemical potential dependence of the equation of state around and above the QCD phase transition. The model correctly reproduces lattice QCD thermodynamics, but it does not provide a proper description of the hadronic phase. For this reason, we merge the holographic equation of state with the hadronic one at temperatures below the phase transition. This new equation of state, that contains a first order phase transition at high chemical potential and a critical point at T=103 MeV and μ_B = 597 MeV, covers a large range in temperature and chemical potential, thus providing a useful tool for hydrodynamic simulations of heavy-ion collisions.