Formation time of quark–gluon plasma in heavy-ion collisions in the holographic shock wave model

We estimate the thermalization time in a holographic model of two colliding shock waves corresponding to heavy-ion collisions. For this, we model the process by the Vaidya metric with a horizon defined by the trapped surface location. We consider two bottom-up AdS/QCD models that in the colliding shock wave approach give a dependence of the multiplicity on energy compatible with the RHIC and LHC results. One model is a bottom-up AdS/QCD confining model, and the other is related to an anisotropic thermalization. We estimate the thermalization time and show that increasing the confining potential decreases the thermalization time and anisotropy accelerates the thermalization.