Determination of the shear viscosity relaxation time at weak and strong coupling

G. S. Denicol, J. Noronha, H. Niemi, D. H. Rischke

Research output: Contribution to journalArticlepeer-review


We investigate the microscopic origin of the relaxation time coefficient in relativistic fluid dynamics. We show that the extraction of the shear viscosity relaxation time via the gradient expansion is ambiguous and in general fails to give the correct result. The correct value for the shear viscosity relaxation time is extracted from the slowest non-hydrodynamic pole of the corresponding retarded Green's function, if such a pole is purely imaginary. According to the AdS/CFT correspondence, in strongly coupled N=4SYM, the non-hydrodynamic poles of the shear stress tensor nearest to the origin have a nonzero real part, which implies that the transient fluid-dynamical equations for this gauge theory are not equivalent to the well-known Israel-Stewart equations.

Original languageEnglish (US)
Article number124177
JournalJournal of Physics G: Nuclear and Particle Physics
Issue number12
StatePublished - Dec 2011
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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