Stringy Pomeron: Entropy and Shear Viscosity

TL;DR

This paper models the soft pomeron as a closed string exchange in AdS5, revealing how entropy and shear viscosity depend on collision rapidity, with implications for understanding scattering processes in high-energy physics.

Contribution

It introduces a novel string-theoretic model of the soft pomeron in AdS5, linking entropy and shear viscosity to rapidity in dipole-dipole scattering.

Findings

Shear viscosity to entropy density ratio decreases with increasing rapidity.

The model predicts a specific dependence of viscosity on N-ality k.

Entropy and temperature are related to the rapidity interval chi.

Abstract

We model the soft pomeron contribution to dipole-dipole scattering as a closed string exchange in AdS5 with a wall. The exchange of closed and long strings is characterized by an apparent Unruh temperature and entropy that are caused by the rapidity interval chi of the collision. We show that the primordial transverse shear viscosity to transverse entropy density ratio is eta-perp/s-perp=(pi k/chi)^2/(8 pi) for scattering dipoles of N-ality k, vanishing at large chi.