Viscosity Bound Violation in Higher Derivative Gravity

By M. Brigante, Hong Liu, R. Myers, S. Shenker, Sho Yaida. 2007

628 citations recorded by the source corpus.

Motivated by the vast string landscape, we consider the shear viscosity to entropy density ratio in conformal field theories dual to Einstein gravity with curvature square corrections. After field redefinitions these theories reduce to Gauss-Bonnet gravity, which has special properties that allow us to compute the shear viscosity nonperturbatively in the Gauss-Bonnet coupling. By tuning of the coupling, the value of the shear viscosity to entropy density ratio can be adjusted to any positive value from infinity down to zero, thus violating the conjectured viscosity bound. At linear order in the coupling, we also check consistency of four different methods to calculate the shear viscosity, and we find that all of them agree. We search for possible pathologies associated with this class of theories violating the viscosity bound.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/f1f6e8e54afb6945b2452e684f8e787cff67b84b

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Citations in the corpus

Comments on holographic entanglement entropy and RG flows (2012, background): “tinct from one another, the gravity action must include higher curvature interactions [32]. In part, this motivated the recent holographic studies of Gauss-Bonnet (GB) gravity [33] | for example, see [34]. In section 6, we will extend our discussion of holographic RG ows to GB gravity with the follo”
Holographic studies of quasi-topological gravity (2010, methodology): “The appearance of such instabilities for five-dimensional GB theory were first noted in [14, 15].”
Gauge/String Duality, Hot QCD and Heavy Ion Collisions (2011, background): “[409, 420] is an example in which this occurs.”
Effect of curvature squared corrections in AdS on the viscosity of the dual gauge theory (2007, neutral): “vhannes Grigoryan, Subhaneil Lahiri and Yuji Tachikawa for useful comments on the manuscript. We appreciate communications with Steve Shenker and collaborators who are about to report similar results [37]. A. Field redeﬁnitions We start with S = Z dDx √ −g R 2κ − Λ+c1R2 +c2RµνRµν and consider gµν ”
AdS7/CFT6, Gauss-Bonnet gravity, and viscosity bound (2009, methodology): “Restricting the group velocity of these states to be bounded by the speed of light (requiring causality of the boundary theory at finite temperature) places non-trivial constraints on the value of Gauss-Bonnet coupling λ [2, 3].”
A Holographic View on Physics out of Equilibrium (2010, background): “Recently, this bound has been shown to be violated in higher-derivative theories of gravity: there are example toy-models such as Gauss-Bonnet gravity [74, 75] and other higherderivative theories [76, 77, 78, 79, 80, 81] and also some string theory inspired constructions”
On holographic entanglement entropy and higher curvature gravity (2011, methodology): “tically AdS black hole solutions were found for Lovelock gravity [19, 24, 25]. These exact solutions then proved useful in discussions of holographic hydrodynamics and consistency of the boundary CFT [19, 24, 26, 27]. Further these models have also been shown to satisfy a holographic c-theorem [20, ”
Lectures on holographic methods for condensed matter physics (2009, background): “For instance, it is now clear that while the value of the ratio of shear viscosity to entropy density, η/s = 1/4π, is universal in classical gravity [123, 72], there are controlled 1/N corrections to this result that can be both positive and negative and which for realistic values of N give signific”
Holographic entanglement entropy in Lovelock gravities (2011, background): “(Work which uses higher derivative gravitational theories to study unitarity constraints in CFTs includes [12-25].”
On graviton non-gaussianities during inflation (2011, neutral): “[30] Mauro Brigante, Hong Liu, Robert C.”
Strongly correlated quantum fluids: ultracold quantum gases, quantum chromodynamic plasmas and holographic duality (2012, background): “The cleanest example of such an effect involves [360, 10, 361] adding the leading irrelevant operator to the bulk gravitational action, the 5d Gauss-Bonnet term, a quadratic scalar built out of the curvature tensors,”
Causality in AdS/CFT and Lovelock theory (2009, methodology): “This was originally shown in 5d where λ ≤ 9 100 [5, 6] and λ ≥ −7/36 [7, 8], the dual theories being 4d N = 1 SCFTs.”
Local Fluid Dynamical Entropy from Gravity (2008, background): “The fact that it is possible to write the current (5.7) in the form (6.1) also demonstrates the Weyl covariance of our current (5.7).”
Causality of holographic hydrodynamics (2009, methodology): “It was observed in [19] that a new instability arises in the dual plasma at λGB = −1/8.”
Many-body chaos and energy dynamics in holography (2018, background): “For example, Gauss-Bonnet gravity (see [43, 46, 47]) may be a good testing ground for this purpose.”