Viscosity Bound and Causality Violation

Abstract

In recent work we showed that, for a class of conformal field theories (CFT) with Gauss-Bonnet gravity dual, the shear viscosity to entropy density ratio, $\eta /s$, could violate the conjectured Kovtun-Starinets-Son viscosity bound, $\eta /s\ge 1/4\pi$. In this paper we argue, in the context of the same model, that tuning $\eta /s$ below $(16/25)(1/4\pi )$ induces microcausality violation in the CFT, rendering the theory inconsistent. This is a concrete example in which inconsistency of a theory and a lower bound on viscosity are correlated, supporting the idea of a possible universal lower bound on $\eta /s$ for all consistent theories.

5 pages, 2 figures; v2: a slight change in the title and minor revisions made, references updated

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Cited by in corpus (29)

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• Shear Viscosity from Effective Couplings of Gravitons
• The applicability of causal dissipative hydrodynamics to relativistic heavy ion collisions
• Universal holographic hydrodynamics at finite coupling
• Shear Viscosity from Gauss-Bonnet Gravity with a Dilaton Coupling
• Thermodynamics of the Maxwell-Gauss-Bonnet anti-de Sitter Black Hole with Higher Derivative Gauge Corrections
• 1/N Effects in Non-Relativistic Gauge-Gravity Duality
• Shear Viscosity from AdS Born-Infeld Black Holes
• Higher derivative effects on eta/s at finite chemical potential
• Constraining relativistic viscous hydrodynamical evolution
• Drag Force of Moving Quark in STU Background
• Phase Transitions and the Perfectness of Fluids
• The Heavy Quark Potential as a Function of Shear Viscosity at Strong Coupling
• Higher derivative corrections to R-charged AdS_5 black holes and field redefinitions
• Sound Modes in Holographic Hydrodynamics for Charged AdS Black Hole
• Causal Viscous Hydrodynamics for Relativistic Heavy Ion Collisions
• Hydrodynamics of N=6 Superconformal Chern-Simons Theories at Strong Coupling
• R^2 Corrections to Asymptotically Lifshitz Spacetimes
• Holographic quark gluon plasma with flavor
• Comments on Bounds on Central Charges in N=1 Superconformal Theories
• The Double Life of Thermal QCD
• Jet Propagation and Mach-Cone Formation in (3+1)-dimensional Ideal Hydrodynamics
• From Thermodynamics to the Bound on Viscosity
• Landscape versus Swampland for Higher Derivative Gravity
• Shear viscosity of pure Yang-Mills theory at strong coupling
• Viscosity to entropy density ratio: violation of the lower bound at small temperatures