Massless Mode and Positivity Violation in Hot QCD

Abstract

We calculate the quark self-energy at one-loop level at high temperature, taking into account contributions from both the (chromo)electric scale $gT$ and the (chromo)magnetic scale $g^{2}T$. While reproducing standard massive excitations due to the electric scale, we uncover a novel massless excitation ascribable to the magnetic scale. The residue of this massless excitation is nonpositive at all temperatures, which consequently gives rise to positivity violation in the quark spectral functions. This demonstrates the profound impact of confinement effects on thermal quark collective excitations, which manifest genuine long-range correlations in the system.

5 pages, 2 figures; v3 - published version

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Cited by in corpus (6)

• Effective description of hot QCD medium in strong magnetic field and longitudinal conductivity
• Revisit to electrical and thermal conductivities, Lorenz number and Knudsen number in thermal QCD in a strong magnetic field
• Effect of the Gribov horizon on the Polyakov loop and vice versa
• Quantization of Yang-Mills Theories without the Gribov Ambiguity
• Non-perturbative study of spectral function and its application in Quark Gluon Plasma
• Gribov horizon, Polyakov loop and finite temperature