Physics

Dr. Ayan Mukhopadhaya
IIT Madras

Abstract:

I will describe a new approach towards constructing effective non-perturbative dynamics of quantum many-body systems. In this approach, we can consistently combine perturbative descriptions for ultraviolet degrees of freedom with a dual description of a strongly coupled infrared, eg in the form of an appropriate holographic classical gravity theory. I will present a toy construction of such a framework and demonstrate that it satisfies many non-trivial consistency checks. I will apply this framework for a simple hybrid model of the quark-gluon plasma consisting of two fluids coupled via their effective metrics. The thermodynamics of this model has features reminiscent of the de-confinement phase transition of QCD featuring both a crossover and a first order phase transition line ending at a second order critical point. Our model also reveals very rich phenomenology for the collective flow -- eg the coupling of the fluids reduces their individual viscosities and at high temperature there is a second sound mode which is slower than the thermodynamic sound but less attenuated. Furthermore, when one of the sectors is described by kinetic theory, we find that the damping rates of a large sector of non-hydrodynamic modes receive mild or no non-perturbative corrections. This may provide qualitative explanation for a few experimental puzzles.