Damping of hard excitations in strongly coupled $\mathcal N\,{=}\,4$ plasma

TL;DR

This paper investigates how high momentum excitations in strongly coupled $ ext{N}=4$ supersymmetric Yang-Mills plasma decay, extending previous work on quasinormal modes and analyzing shock wave behavior.

Contribution

It extends and clarifies calculations of quasinormal mode spectra and confirms universal corrections to dispersion relations in strongly coupled plasma.

Findings

Universal $|{f q}|^{-1/3}$ correction to dispersion relation.

Narrow shocks can be described as superpositions of quasinormal modes.

Attenuation and profile evolution of shocks analyzed.

Abstract

The damping of high momentum excitations in strongly coupled maximally supersymmetric Yang-Mills plasma is studied. Previous calculations of the asymptotic behavior of the quasinormal mode spectrum are extended and clarified. We confirm that subleading corrections to the lightlike dispersion relation $\omega({\bf q}) = |{\bf q}|$ have a universal $|{\bf q}|^{-1/3}$ form. Sufficiently narrow, weak planar shocks may be viewed as coherent superpositions of short wavelength quasinormal modes. The attenuation and evolution in profile of narrow planar shocks are examined as an application of our results.