Results 1  10
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15
Nonlinear Fluid Dynamics from Gravity
, 2007
"... Black branes in AdS5 appear in a four parameter family labeled by their velocity and temperature. Promoting these parameters to Goldstone modes or collective coordinate fields – arbitrary functions of the coordinates on the boundary of AdS5 – we use Einstein’s equations together with regularity requ ..."
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Cited by 122 (4 self)
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Black branes in AdS5 appear in a four parameter family labeled by their velocity and temperature. Promoting these parameters to Goldstone modes or collective coordinate fields – arbitrary functions of the coordinates on the boundary of AdS5 – we use Einstein’s equations together with regularity requirements and boundary conditions to determine their dynamics. The resultant equations turn out to be those of boundary fluid dynamics, with specific values for fluid parameters. Our analysis is perturbative in the boundary derivative expansion but is valid for arbitrary amplitudes. Our work may be regarded as a derivation of the nonlinear equations of boundary fluid dynamics from gravity. As a concrete application we find an explicit expression for the expansion of this fluid stress tensor including terms up to second order in the derivative expansion.
Nonlinear viscous hydrodynamics in various dimensions using AdS/CFT
, 2008
"... We compute coefficients of twoderivative terms in the hydrodynamic energy momentum tensor of a viscous fluid which has an AdSD dual with 3 ≤ D ≤ 7. For the case of D = 3 we obtain an exact AdS3 black hole solution, valid to all orders in a derivative expansion, dual to a perfect fluid in 1 + 1 dime ..."
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Cited by 41 (3 self)
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We compute coefficients of twoderivative terms in the hydrodynamic energy momentum tensor of a viscous fluid which has an AdSD dual with 3 ≤ D ≤ 7. For the case of D = 3 we obtain an exact AdS3 black hole solution, valid to all orders in a derivative expansion, dual to a perfect fluid in 1 + 1 dimensions.
ENERGY LOSS IN A STRONGLY COUPLED THERMAL MEDIUM AND THE GAUGESTRING DUALITY
, 2009
"... We review methods developed in the gaugestring duality to treat energy loss by energetic probes of a strongly coupled thermal medium. After introducing the black hole description of the thermal medium, we discuss the trailing string behind a heavy quark and the drag force that it implies. We then e ..."
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Cited by 34 (1 self)
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We review methods developed in the gaugestring duality to treat energy loss by energetic probes of a strongly coupled thermal medium. After introducing the black hole description of the thermal medium, we discuss the trailing string behind a heavy quark and the drag force that it implies. We then explain how to solve the linearized Einstein equations in the presence of the trailing string and extract from the solutions the energy density and the Poynting vector of the dual gauge theory. We summarize some efforts to compare these calculations to heavy ion phenomenology.
Higher Derivative Corrections to Shear Viscosity from Graviton’s Effective Coupling
, 2009
"... The shear viscosity coefficient of strongly coupled boundary gauge theory plasma depends on the horizon value of the effective coupling of transverse graviton moving in black hole background. The proof for the above statement is based on the canonical form of graviton’s action. But in presence of ..."
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Cited by 21 (0 self)
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The shear viscosity coefficient of strongly coupled boundary gauge theory plasma depends on the horizon value of the effective coupling of transverse graviton moving in black hole background. The proof for the above statement is based on the canonical form of graviton’s action. But in presence of generic higher derivative terms in the bulk Lagrangian the action is no longer canonical. We give a procedure to find an effective action for graviton (to first order in coefficient of higher derivative term) in canonical form in presence of any arbitrary higher derivative terms in the bulk. From that effective action we find the effective coupling constant for transverse graviton which in general depends on the radial coordinate r. We also argue that horizon value of this effective coupling is related to the shear viscosity coefficient of the boundary fluid in higher derivative gravity. We explicitly check this procedure for two specific examples: (1) four derivative action and (2) eight derivative action (Weyl 4 term). For both cases we show that our results for shear viscosity coefficient (upto first order in coefficient of higher derivative term) completely agree with the existing results
The StressEnergy Tensor of Flavor Fields from AdS/CFT
"... Abstract: We use the AdS/CFT correspondence to study the transport properties of massive N = 2 hypermultiplet fields in an N = 4 SU(Nc) superYangMills theory plasma in the large Nc, large ’t Hooft coupling limit, and in the presence of a baryon number chemical potential and external electric and m ..."
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Cited by 20 (2 self)
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Abstract: We use the AdS/CFT correspondence to study the transport properties of massive N = 2 hypermultiplet fields in an N = 4 SU(Nc) superYangMills theory plasma in the large Nc, large ’t Hooft coupling limit, and in the presence of a baryon number chemical potential and external electric and magnetic fields. In particular, we compute the flavor fields’ contribution to the stressenergy tensor. We find infrared divergences in the stressenergy tensor, arising from the flavor fields ’ constant rate of energy and momentum loss. We regulate these divergences and extract the energy and momentum loss rates from the divergent terms. We also check our result in various limits in which the divergences are absent. The supergravity dual is a system of D7branes, with a particular configuration of worldvolume fields, probing an AdSSchwarzschild background. The supergravity calculation amounts to computing the stressenergy tensor of the D7branes.
Higher Derivative Corrections to Locally Black Brane Metrics
 JHEP
"... Abstract: In this paper we generalize the construction of locally boosted black brane space time to higher derivative gravities. We consider the GaussBonnet term (with coefficient α ′) as a toy example. We find the solution to the α ′ corrected Einstein equations to first order in the boundary deri ..."
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Cited by 17 (2 self)
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Abstract: In this paper we generalize the construction of locally boosted black brane space time to higher derivative gravities. We consider the GaussBonnet term (with coefficient α ′) as a toy example. We find the solution to the α ′ corrected Einstein equations to first order in the boundary derivative expansion. This allows us to find the α ′ corrections to the boundary stress tensor in the presence of the GaussBonnet term in the bulk action. We therefore obtain the ratio of shear viscosity to entropy which agrees with other methods of computation in the
Forced Fluid Dynamics from Gravity
, 2008
"... We generalise the computations of [1] to generate long wavelength, asymptotically locally AdS5 solutions to the Einsteindilaton system with a slowly varying boundary dilaton field and a weakly curved boundary metric. Upon demanding regularity, our solutions are dual, under the AdS/CFT correspondenc ..."
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Cited by 16 (1 self)
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We generalise the computations of [1] to generate long wavelength, asymptotically locally AdS5 solutions to the Einsteindilaton system with a slowly varying boundary dilaton field and a weakly curved boundary metric. Upon demanding regularity, our solutions are dual, under the AdS/CFT correspondence, to arbitrary fluid flows in the boundary theory formulated on a weakly curved manifold with a prescribed slowly varying coupling constant. These solutions turn out to be parametrised by fourvelocity and temperature fields that are constrained to obey the boundary covariant Navier Stokes equations with a dilaton dependent forcing term. We explicitly evaluate the stress tensor and Lagrangian as a function of the velocity, temperature, coupling constant and curvature fields, to second order in the derivative expansion and demonstrate the Weyl covariance of these expressions. We also construct the event horizon of the dual solutions to second order in the derivative expansion, and use the area form on this event horizon to construct an entropy current for the dual fluid. As a check of our constructions we expand the exactly known solutions for rotating black holes in global AdS5 in a boundary derivative expansion and find perfect agreement with all our results upto second order. We also find other simple solutions of the forced fluid mechanics equations and discuss their bulk interpretation. Our results may aid in determining a bulk dual to forced flows exhibiting steady state turbulence.
Gauge/String Duality, Hot QCD and Heavy Ion Collisions
, 2014
"... Over the last decade, both experimental and theoretical advances have brought the need for strong coupling techniques in the analysis of deconfined QCD matter and heavy ion collisions to the forefront. As a consequence, a fruitful interplay has developed between analyses of stronglycoupled nonabel ..."
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Cited by 10 (0 self)
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Over the last decade, both experimental and theoretical advances have brought the need for strong coupling techniques in the analysis of deconfined QCD matter and heavy ion collisions to the forefront. As a consequence, a fruitful interplay has developed between analyses of stronglycoupled nonabelian plasmas via the gauge/string duality (also referred to as the AdS/CFT correspondence) and the phenomenology of heavy ion collisions. We review some of the main insights gained from this interplay to date. To establish a common language, we start with an introduction to heavy ion phenomenology and finitetemperature QCD, and a corresponding introduction to important concepts and techniques in the gauge/string duality. These introductory sections are written for nonspecialists, with the goal of bringing readers ranging from beginning graduate students to experienced practitioners of either QCD or gauge/string duality to the point that they understand enough about both fields that they can then appreciate their interplay in all appropriate contexts. We then review the current stateofthe art in the application of the duality to the description of the dynamics of strongly coupled plasmas, with emphases that include: its thermodynamic, hydrodynamic and transport properties; the way it both modifies the dynamics of, and is perturbed by, highenergy or heavy quarks passing through it; and the physics of quarkonium mesons within it. We seek throughout to stress the lessons that can be extracted from these computations for heavy ion physics as well as to discuss future directions and open problems for the field. ar X iv
Universality of second order transport
, 2008
"... coefficients from the gaugestring duality ..."
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