Abstract:
We construct a nonperturbative holographic QCD model that simultaneously reproduces the lattice equation of state and the temperature dependence of transport coefficients across the deconfinement crossover. Embedding a Gauss–Bonnet term nonminimally coupled to a dilaton within an Einstein–Maxwell–dilaton framework, we calibrate all potentials at zero chemical potential to lattice thermodynamics and compute the shear viscosity–to–entropy ratio $\eta/s$ and bulk viscosity–to–entropy ratio $\zeta/s$ without small-coupling expansions. The model exhibits a high-temperature plateau in $\eta/s$ above critical temperature $T_c$, a pronounced minimum of $\eta/s$, and a peak in $\zeta/s$ near the pseudo-critical temperature, in agreement with expectations from critical dynamics. This unified holographic construction shows that higher-curvature corrections tied to scalar dynamics capture both equilibrium and real-time properties of the quark–gluon plasma.
