Holographic bulk viscosity: GPR vs EO

A. Buchel (1, 2) , U. Gursoy (3) , E. Kiritsis (4, 5)

1 Perimeter Institute
2 UWO - University of Western Ontario
3 CERN - European Organization for Nuclear Research
4 APC - THEORIE
5 UOC - University of Crete [Heraklion]

Recently Eling and Oz (EO) proposed a formula for the holographic bulk viscosity, in arXiv:1103.1657, derived from the null horizon focusing equation. This formula seems different from that obtained earlier by Gubser, Pufu and Rocha (GPR) in arXiv:0806.0407 calculated from the IR limit of the two-point function of the trace of the stress tensor. The two were shown to agree only for some simple scaling cases. We point out that the two formulae agree in two non-trivial holographic theories describing RG flows. The first is the strongly coupled $\mathbb{N}$=2$^*$ gauge theory plasma. The second is the semi-phenomenological model of Improved Holographic QCD.

Mots clés: Gauge-gravity correspondence; Duality in Gauge Field Theories; AdS-CFT

Domaines: Physique des Hautes Energies - Théorie [hep-th]

A. Buchel, U. Gursoy, E. Kiritsis. Holographic bulk viscosity: GPR vs EO. Journal of High Energy Physics, 2011, 9, pp.95. ⟨10.1007/JHEP09(2011)095⟩. ⟨in2p3-00714892⟩