Sonic booms and diffusion wakes generated by a heavy quark in thermal AdS/CFT

TL;DR

The paper uses AdS/CFT to compute the stress-tensor disturbance produced by a heavy quark moving through a thermal N=4 SYM plasma, revealing both a sonic boom and a diffusion wake. It develops a robust UV/IR subtraction and FFT-based reconstruction to obtain the position-space Poynting vector and decomposes the energy flow into sound and diffusion channels. The results show that, in the plasma rest frame, energy lost to sound modes and energy fed by the diffusion wake follow a precise ratio, highlighting the prominence of the sonic contribution alongside a non-negligible diffusion effect with potential implications for jet-quenching phenomenology. The study provides a first-principles, all-scales description of dissipation from near-field to hydrodynamic regimes in a strongly coupled gauge theory.

Abstract

We evaluate the Poynting vector generated by a heavy quark moving through a thermal state of N=4 gauge theory using AdS/CFT. A significant diffusion wake is observed as well as a Mach cone. We discuss the ratio of the energy going into sound modes to the energy coming in from the wake.

Figures (1)

• Figure 1: Energy density and components of the Poynting vector. Sp means $S_\perp = \sqrt{S_2^2+S_3^2}$. $|X|=1$ corresponds to $0.2\,{\rm fm}$ from the quark if $T \approx 318\,{\rm MeV}$. Red means positive, blue means negative, and white is close to zero. The lower right plot is colored according to the magnitude of $\vec{S}$, while the arrows show the direction of $\vec{S}$. For $X_1 > 3$, $\vec{S}$ is so small that we probably cannot determine its direction reliably. The Mach cone is shown in dashed green, and the solid blue line shows where the large distance analytic estimate of the diffusion wake profile reaches half its maximum value.