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On conformal field theories
 in fourdimensions,” Nucl. Phys. B533
, 1998
"... We review the generalization of field theory to spacetime with noncommuting coordinates, starting with the basics and covering most of the active directions of research. Such theories are now known to emerge from limits of M theory and string theory, and to describe quantum Hall states. In the last ..."
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Cited by 361 (0 self)
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We review the generalization of field theory to spacetime with noncommuting coordinates, starting with the basics and covering most of the active directions of research. Such theories are now known to emerge from limits of M theory and string theory, and to describe quantum Hall states. In the last few years they have been studied intensively, and many qualitatively new phenomena have been discovered, both on the classical and quantum level. Submitted to Reviews of Modern Physics.
Viscosity in strongly interacting quantum field theories from black hole physics
, 2004
"... The ratio of shear viscosity to volume density of entropy can be used to characterize how close a given fluid is to being perfect. Using string theory methods, we show that this ratio is equal to a universal value of �/4πkB for a large class of strongly interacting quantum field theories whose dual ..."
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Cited by 168 (4 self)
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The ratio of shear viscosity to volume density of entropy can be used to characterize how close a given fluid is to being perfect. Using string theory methods, we show that this ratio is equal to a universal value of �/4πkB for a large class of strongly interacting quantum field theories whose dual description involves black holes in anti–de Sitter space. We provide evidence that this value may serve as a lower bound for a wide class of systems, thus suggesting that black hole horizons are dual to the most ideal fluids.
Scalar speed limits and cosmology: Acceleration from D cceleration
 Phys. Rev. D70 (2004) 103505, hepth/0310221
"... Causality on the gravity side of the AdS/CFT correspondence restricts motion on the moduli space of the N = 4 super Yang Mills theory by imposing a speed limit on how fast the scalar field may roll. This effect can be traced to higher derivative operators arising from integrating out light degrees o ..."
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Cited by 166 (11 self)
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Causality on the gravity side of the AdS/CFT correspondence restricts motion on the moduli space of the N = 4 super Yang Mills theory by imposing a speed limit on how fast the scalar field may roll. This effect can be traced to higher derivative operators arising from integrating out light degrees of freedom near the origin. In the strong coupling limit of the theory, the dynamics is well approximated by the DiracBornInfeld Lagrangian for a probe D3brane moving toward the horizon of the AdS Poincare patch, combined with an estimate of the (ultimately suppressed) rate of particle and string production in the system. We analyze the motion of a rolling scalar field explicitly in the strong coupling regime of the field theory, and extend the analysis to cosmological systems obtained by coupling this type of field theory to four dimensional gravity. This leads to a mechanism for slow roll inflation for a massive scalar at subPlanckian VEV without need for a flat potential (realizing a version of kinflation in a microphysical framework). It also leads to a variety of novel FRW cosmologies, some of which
Chiral rings and anomalies in supersymmetric gauge theory
 JHEP
, 2002
"... Motivated by recent work of Dijkgraaf and Vafa, we study anomalies and the chiral ring structure in a supersymmetric U(N) gauge theory with an adjoint chiral superfield and an arbitrary superpotential. A certain generalization of the Konishi anomaly leads to an equation which is identical to the loo ..."
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Cited by 160 (7 self)
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Motivated by recent work of Dijkgraaf and Vafa, we study anomalies and the chiral ring structure in a supersymmetric U(N) gauge theory with an adjoint chiral superfield and an arbitrary superpotential. A certain generalization of the Konishi anomaly leads to an equation which is identical to the loop equation of a bosonic matrix model. This allows us to solve for the expectation values of the chiral operators as functions of a finite number of “integration constants. ” From this, we can derive the DijkgraafVafa relation of the effective superpotential to a matrix model. Some of our results are applicable to more general theories. For example, we determine the classical relations and quantum deformations of the chiral ring of N = 1 super YangMills theory with SU(N) gauge group, showing, as one consequence, that all supersymmetric vacua of this theory have a nonzero chiral condensate.
Holographic duality with a view toward manybody physics
, 2009
"... These are notes based on a series of lectures given at the KITP workshop Quantum Criticality and the AdS/CFT Correspondence in July, 2009. The goal of the lectures was to introduce condensed matter physicists to the AdS/CFT correspondence. Discussion of string theory and of supersymmetry is avoided ..."
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Cited by 148 (2 self)
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These are notes based on a series of lectures given at the KITP workshop Quantum Criticality and the AdS/CFT Correspondence in July, 2009. The goal of the lectures was to introduce condensed matter physicists to the AdS/CFT correspondence. Discussion of string theory and of supersymmetry is avoided to the extent possible.
The Analytic Bethe Ansatz for a Chain with Centrally Extended su(22) Symmetry
, 2006
"... We investigate the integrable structure of spin chain models with centrally extended su(22) and psu(2, 24) symmetry. These chains have their origin in the planar AdS/CFT correspondence, but they also contain the onedimensional Hubbard model as a special case. We begin with an overview of the repr ..."
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Cited by 140 (6 self)
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We investigate the integrable structure of spin chain models with centrally extended su(22) and psu(2, 24) symmetry. These chains have their origin in the planar AdS/CFT correspondence, but they also contain the onedimensional Hubbard model as a special case. We begin with an overview of the representation theory of centrally extended su(22). These results are applied in the construction and investigation of an interesting Smatrix with su(22) symmetry. In particular, they enable a remarkably simple proof of the YangBaxter relation. We also show the equivalence of the Smatrix to Shastry’s Rmatrix and thus uncover a hidden supersymmetry in the integrable structure of the Hubbard model. We then construct eigenvalues of the corresponding transfer matrix in order to formulate an analytic Bethe ansatz. Finally, the form of transfer matrix eigenvalues for models with psu(2, 24) symmetry is sketched.
A Covariant Holographic Entanglement Entropy Proposal
, 2008
"... With an aim towards understanding the timedependence of entanglement entropy in generic quantum field theories, we propose a covariant generalization of the holographic entanglement entropy proposal of hepth/0603001. Apart from providing several examples of possible covariant generalizations, we s ..."
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Cited by 140 (20 self)
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With an aim towards understanding the timedependence of entanglement entropy in generic quantum field theories, we propose a covariant generalization of the holographic entanglement entropy proposal of hepth/0603001. Apart from providing several examples of possible covariant generalizations, we study a particular construction based on lightsheets, motivated in similar spirit to the covariant entropy bound underlying the holographic principle. In particular, we argue that the entanglement entropy associated with a specified region on the boundary in the context of the AdS/CFT correspondence is given by the area of a codimension two bulk surface with vanishing expansions of null geodesics. We demonstrate our construction with several examples to illustrate its reduction to the holographic entanglement entropy proposal in static spacetimes. We further show how this proposal may be used to understand the time evolution of entanglement entropy in a time varying QFT state dual to a collapsing black hole background. Finally, we use our proposal to argue that the Euclidean wormhole geometries with multiple boundaries should be regarded as states in a noninteracting but entangled set of QFTs, one associated to each boundary.
The holographic principle
 Rev. Mod. Phys
, 2002
"... There is strong evidence that the area of any surface limits the information content of adjacent spacetime regions, at 1.4 ×10 69 bits per square meter. We review the developments that have led to the recognition of this entropy bound, placing special emphasis on the quantum properties of black hole ..."
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Cited by 127 (8 self)
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There is strong evidence that the area of any surface limits the information content of adjacent spacetime regions, at 1.4 ×10 69 bits per square meter. We review the developments that have led to the recognition of this entropy bound, placing special emphasis on the quantum properties of black holes. The construction of lightsheets, which associate relevant spacetime regions to any