Conclusion and a Look Ahead

Abstract

These notes aim at a self-contained introduction to applications of the gauge/gravity correspondence to the theory of strong interactions, QCD, with an emphasis on describing the thermodynamic and transport properties of the quark-gluon plasma. We outlined construction of the improved holographic QCD model, explained how to fix its parameters, the resulting structure of the ground and thermal states, calculation of thermodynamic observables and their comparison to the first-principles theory i.e. lattice QCD, how the holographic and hydrodynamic descriptions are merged and the calculation of the transport coefficients such as the bulk and the shear viscosities. We also focused on the electromagnetic properties of strong interactions within the holographic approach to QCD. In particular, we discussed what holography has to say about some of the open problems such as how the magnetic fields affect the phase diagram, how do the transport coefficients depend on it, and the underlying mechanisms behind recently discovered phenomena such as the inverse magnetic catalysis.