Theory of Initial State Fluctuations, Thermalization and CGC

We describe how the dynamics of strongly correlated gluons at high parton densities lead to a natural understanding of di-hadron correlations in high-multiplicity p+p and p+Pb collisions. The physics of which is intimately related to quantum fluctuations responsible for the decoherence of the strongly occupied initial classical fields generated in heavy-ion collisions. We outline a program to compute the effect of real time evolution of unstable quantum modes on the bulk dynamics of the system and demonstrate within a scalar $\phi^4$ theory that an equation of state and hydrodynamic behavior is obtained.