Debye screening in strongly coupled N=4 supersymmetric Yang-Mills plasma

TL;DR

The paper investigates Debye screening in strongly coupled N=4 SYM plasma using AdS/CFT, focusing on Polyakov loop correlators as screening probes. It identifies the Debye mass as set by the lightest CT-odd supergravity mode and the mass gap by the lightest CT-even mode, yielding precise strong-coupling values $m_{\rm gap}=2.3361\, (\pi T)$ and $m_D=3.4041\, (\pi T)$, with the Im$\mathcal{P}$ channel controlled by $\tilde{m}=5.1085\, (\pi T)$. The correlator exhibits a crossover at $r_*=0.240/T$ between a smooth connected worldsheet and a horizon-exchange dominated regime, illustrating the nonperturbative structure of screening at strong coupling. When contrasted with lattice QCD at $2T_c$, the ratio $m_D/m_{\rm gap}\approx1.46$ aligns closely, suggesting QCD at this temperature behaves like intermediate coupling SYM; the work also discusses weak-to-strong coupling interpolations and outlines subleading $\lambda^{-3/2}$ corrections and future extensions to flavor sectors.

Abstract

Using the AdS/CFT correspondence, we examine the behavior of correlators of Polyakov loops and other operators in N=4 supersymmetric Yang-Mills theory at non-zero temperature. The implications for Debye screening in this strongly coupled non-Abelian plasma, and comparisons with available results for thermal QCD, are discussed.