Researchers have explored the thermodynamics and transport properties of the quark-gluon plasma (QGP) using a holographic quantum chromodynamics (QCD) model. This model extends the Einstein-Maxwell-Dilaton framework by incorporating Gauss-Bonnet corrections. The model parameters were adjusted using thermodynamic data from lattice QCD, allowing for an accurate description of the state of matter at different temperatures and baryonic chemical potentials. The study focused on the equation of state at zero and finite baryonic chemical potential, as well as the structure of the phase diagram in the temperature-chemical potential plane.

The analysis also examined the shear and bulk viscosity to entropy ratios, $\eta/s$ and $\zeta/s$, respectively, through fluctuation equations. For a constant Gauss-Bonnet coupling, the model reasonably reproduces the equation of state and predicts a temperature-dependent $\eta/s$ ratio. However, this $\eta/s$ profile was found to be monotonic near the transition region, which differs from phenomenological expectations that suggest non-monotonic behavior in this area.

When the Gauss-Bonnet coupling was allowed to depend on the dilaton, the model generated a non-monotonic profile for $\eta/s$ and a peak in $\zeta/s$, while maintaining consistency with thermodynamic constraints. This more flexible model configuration predicts a critical point in the phase diagram in a region of phenomenological interest. These results are crucial for a better understanding of the properties of the QGP, a state of matter that existed in the early universe and is recreated in heavy-ion collision experiments.