Time-like Gravitational Formfactors and Shear Viscosity

TL;DR

This paper identifies a gravitational form factor analogous to shear viscosity, linking it to exotic hybrid mesons in the time-like region and estimating the viscosity to entropy ratio within a holographic framework.

Contribution

It introduces a gravitational form factor related to shear viscosity and connects it to hybrid mesons and dissipation in the crossed channel, providing new insights into their properties.

Findings

The gravitational form factor is linked to hybrid mesons.

The viscosity to entropy density ratio is estimated.

Smallness of this ratio aligns with holographic bounds.

Abstract

The gravitational formfactor similar to shear viscosity is identified. In the time-like region it corresponds to the contribution of exotic hybrid meson. The exotic quantum numbers may be considered as a counterpart of dissipation in crossed channel. The ratio of viscosity to entropy density is estimated. The smallness due to holographic bound corresponds to the relative smallness of coupling of hybrid meson and the intrinsic transverse momentum, being the dynamical counterpart of temperature.