Phase structure of 2+1-flavor QCD from an Einstein-dilaton-flavor holographic model

A bstract We construct a 2 + 1-flavor holographic QCD model within the Einstein-dilaton-flavor framework and investigate its phase structure. At zero chemical potential, the model reproduces the equation of state and the chiral transition in quantitative agreement with lattice QCD results. By varying the light and strange quark masses, we map out the quark-mass dependence of the transition order and obtain the corresponding phase diagram, which is consistent with phase structures extracted from lattice simulations and other nonperturbative approaches. In particular, the predicted first-order region is found to be small, in line with the most recent lattice QCD analyses. We further examine the critical behavior along the second-order boundaries and in the tricritical region, finding that the critical exponents exhibit mean-field scaling characteristic of classical holographic constructions. Taken together, these results provide a coherent holographic description of QCD thermodynamics and its phase structure across a wide range of quark-mass regimes.