Transport coefficients of the quark-gluon plasma at the critical point and across the first-order line

Understand

A bottom-up Einstein-Maxwell-Dilaton holographic model is used to compute, for the first time, the behavior of several transport coefficients of the hot and baryon-rich strongly coupled quark-gluon plasma at the critical point and also across the first-order phase transition line in the phase diagram.

• The observables under study are of the shear and bulk viscosities, baryon diffusion, thermal conductivity, the jet quenching parameter $\hat{q}$, as well as the heavy-quark drag force and Langevin diffusion coefficients.
• These calculations provide a phenomenologically promising estimate for these coefficients, given that our model quantitatively reproduces lattice QCD thermodynamics results, both at zero and finite baryon density, besides naturally incorporating the nearly-perfect fluidity of the quark-gluon plasma.
• We find that the diffusion of baryon charge, and also the shear and bulk viscosities, are suppressed with increasing baryon density, indicating that the medium becomes even closer to perfect fluidity at large densities.