An effective description of momentum diffusion in a charged plasma from holography

Abstract

We discuss the physics of momentum diffusion in a charged plasma. Following the holographic strategy outlined in [1] we construct an open effective field theory for the low-lying modes of the conserved currents. The charged plasma is modeled holographically in terms of a Reissner-Nordström-AdS d+1 black hole. We analyze graviton and photon fluctuations about this background, decoupling in the process the long-lived momentum diffusion mode from the short-lived charged transport mode. Furthermore, as in the aforementioned reference, we argue that the dynamics of these modes are captured by a set of designer scalars in the background geometry. These scalars have their gravitational coupling modulated by an auxiliary dilaton with long-lived modes being weakly coupled near the spacetime asymptopia. Aided by these observations, we obtain the quadratic effective action that governs the fluctuating hydrodynamics of charge current and stress tensor, reproducing in the process transport data computed previously. We also point out an interesting length scale lying between the inner and outer horizon radii of the charged black hole associated with Ohmic conductivity.

Holographic Schwinger-Keldysh field theory of SU(2) diffusion

“…The results of [1,29] are in perfect agreement with that constructed within the non-equilibrium EFT framework [2]. Recently, the holographic SK contour [1] attracted a lot of attention in various holographic settings [37][38][39][40][41][42][43][44][45][46].…”

Schwinger-Keldysh effective action for relativistic Brownian particle in AdS-CFT

“…Particularly, the latter adopted the holographic SK contour [45] (see [46][47][48] for an alternative holographic prescription for SK contour) and derived the effective action for a nonlinear Langevin theory [10,11]. Over the past two years, the holographic SK contour [45] attracted a lot of attention in the study of SK field theory [44,[49][50][51][52][53][54][55][56].…”