April 13: “An effective field theory of stochastic diffusion from gravity” by Mukund Rangamani

Date : April 13, 2021, 16:00 CEST

Link: https://zoom.us/j/98810153463?pwd=WWtWQXBURGw1NTZ2Rm82QThPbW42dz09

Title: An effective field theory of stochastic diffusion from gravity

Abstract:  Planar black holes in AdS have long-lived quasinormal modes which capture the physics of charge and momentum diffusion in the dual field theory. We would like to understand the effective description of this system using an external field that couples to these slow degrees of freedom. Using holography we will construct universal gauge invariant framework which captures the physics of stochastic diffusion. We will argue that  designer scalar with a gravitational coupling governed by a single parameter (the Markovianity index) captures the effective dynamics and reproduces the physics of  diffusive Hawking photons and gravitons. As a corollary we will derive the quadratic effective action that governs fluctuating hydrodynamics of the dual CFT.