Universal hydrodynamic flow in holographic planar shock collisions

TL;DR

This paper investigates shock wave collisions in a holographic model, revealing universal hydrodynamic behavior after initial non-universal transient effects, and finds that particle rapidity distributions are Gaussian.

Contribution

It demonstrates the universality of hydrodynamic flow in holographic shock collisions despite initial profile-dependent differences.

Findings

Post-collision stress tensor shows transient non-universal behavior near the light cone.

Hydrodynamic evolution becomes universal across various shock profiles and widths.

Rapidity distribution of produced particles is well approximated by a Gaussian.

Abstract

We study the collision of planar shock waves in AdS$_5$ as a function of shock profile. In the dual field theory the shock waves describe planar sheets of energy whose collision results in the formation of a plasma which behaves hydrodynamically at late times. We find that the post-collision stress tensor near the light cone exhibits transient non-universal behavior which depends on both the shock width and the precise functional form of the shock profile. However, over a large range of shock widths, including those which yield qualitative different behavior near the future light cone, and for different shock profiles, we find universal behavior in the subsequent hydrodynamic evolution. Additionally, we compute the rapidity distribution of produced particles and find it to be well described by a Gaussian.