Hall 123

Studies of ultra-relativistic macroscopic phenomena including real time correlations

Toshali Mitra

IMSc

The existence of hydrodynamic attractors in various microscopic theories and phenomenological models has paved the way for understanding hydrodynamization in out-of- equilibrium systems. The thesis studies a far-away-from equilibrium system in the context of Bjorken model of QGP, boost-invariant expansion along the collisional axis. It explores the effect of continuous symmetry breaking and the corresponding phase transition on hydrodynamization in the Bjorken expanding system and also compute real-time hydrodynamic correlation functions of a system that hydrodynamizes at late time. In addition, we also explore thermalisation in a hybrid system coupled in semi-holographic framework.

In this presentation, I will discuss the formulation of an effective theory of dissipative superfluid and evolution of the dissipative system in out-of-equilibrium situation in the context of Bjorken flow. I will demonstrate the existence of hydrodynamic attractor and even number of U(1) symmetry breaking fixed points in the unbroken and broken phase of this system. I will discuss a method to compute real time correlation functions of an expanding system using a holographic approach in the limit where the state hydrodynamizes. In this limit, real-time correlation function of the expanding system assumes a thermal form with constant temperature. I will conclude the presentation by providing a generic proof of thermalisation in a hybrid system involving a weakly self- interacting and a strongly self-interacting sector, coupled in a semi-holographic framework.