Bulk viscosity of strongly coupled plasmas with holographic duals

By S. Gubser, Silviu S. Pufu, F. Rocha. 2008

171 citations recorded by the source corpus.

We explain a method for computing the bulk viscosity of strongly coupled thermal plasmas dual to supergravity backgrounds supported by one scalar field. Whereas earlier investigations required the computation of the leading dissipative term in the dispersion relation for sound waves, our method requires only the leading frequency dependence of an appropriate Green's function in the low-frequency limit. With a scalar potential chosen to mimic the equation of state of QCD, we observe a slight violation of the lower bound on the ratio of the bulk and shear viscosities conjectured in [1].

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/72dec6257e3352a53f2d39ce3d21bd7e46a611fc

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Citations in the corpus

Heavy ions and string theory (2013, methodology): “We may demonstrate this by using an ω → 0 expansion to analytically match the r → rH and r →∞ limits; we take our discussion from [126].”
Gauge/String Duality, Hot QCD and Heavy Ion Collisions (2011, methodology): “However, the bulk viscosity has been calculated both in more sophisticated examples of the gauge/string duality in which the gauge theory is not conformal [422–426], as well as in AdS/QCD models that incorporate an increase in the bulk viscosity near a deconfinement phase transition [51,427,428].”
Universal hydrodynamics of non-conformal branes (2009, result): “ is ﬁxed. A diﬀerent ratio in the nonconformal ﬂuid would uplift to a non-vanishing bulk viscosity in the conformal ﬂuid, which is forbidden by conformal symmetry. A related argument was presented in [21]. Hence the ratio of bulk and shear viscosity in the non-conformal ﬂuid is dictated by the gener”
Thermal transport and drag force in improved holographic QCD (2009, methodology): “t [49] is due to our different normalization of the dilaton kinetic term.”
From Gauge-string duality to strong interactions: A Pedestrian's guide (2009, background): “Computations of ζ in theories where the equation of state is close to that of QCD have appeared in (57,58); see also the closely related work (59), where the equation of state is closer to that of pure Yang-Mills theory.”
Generalized holographic quantum criticality at finite density (2011, methodology): “Not surprisingly, this metric is that of an AdSp+q+1 -Schwarzschild black-hole, [30, 18, 19, 17]:”
Improved Holographic QCD (2010, methodology): “Here, we follow the method proposed by [74].”
Bulk viscosity of QCD matter near the critical temperature (2007, background): “The authors also observe an increase of bulk viscosity near the deconfinement temperature [33, 34], with the numerical values somewhat smaller than reported in this paper.”
The gravity dual of a p-wave superconductor (2008, background): “ized in the xdirection can be expanded for large ras Ax = e−iωt " A(0) x + A(1) x r +O 1 r2 # , (13) 7Modulo some issues related to behavior near ω = 0, this prescription can also be justiﬁed [19] by the fact that if one analytically continues GR ij (ω) to the upper half-plane, then at the Mat”