http://inspirehep.net/record/499969/files/arXiv:hep-th_9905111.pdf

Large N Field Theories, String Theory and Gravity

Superstring theoryをめぐって(放談室)

Journal of Physics Condensed Matter: Preface

In the first part of this paper we find supergravity solutions corresponding to branes on worldvolumes of the form Rd×Σ where Σ is a Riemann surface. These theories arise when we wrap branes on holomorphic Riemann surfaces inside K3 or CY manifolds. In some cases the theory at low energies is a conformal field theory with two less dimensions. We find some non-singular supersymmetric compactifications of M-theory down to AdS5. We also propose a criterion for permissible singularities in supergravity solutions. In the second part of this paper, which can be read independently of the first, we show that there are no non-singular Randall-Sundrum or de-Sitter compactifications for large class of gravity theories.

http://cds.cern.ch/record/445802/files/0007018.pdf

Supergravity description of field theories on curved manifolds and a no go theorem

Flux compactifications in string theory: A Comprehensive review

We consider multi-energy level distributions in the SYK model, and in particular, the role of global fluctuations in the density of states of the SYK model The connected contributions to the moments of the density of states go to zero as $N \to \infty$, however, they are much larger than the standard RMT correlations We provide a diagrammatic description of the leading behavior of these connected moments, showing that the dominant diagrams are given by 1PI cactus graphs, and derive a vector model of the couplings which reproduces these results We generalize these results to the first subleading corrections, and to fluctuations of correlation functions In either case, the new set of correlations between traces (ie between boundaries) are not associated with, and are much larger than, the ones given by topological wormholes The connected contributions that we discuss are the beginning of an infinite series of terms, associated with more and more information about the ensemble of couplings, which hints towards the dual of a single realization In particular, we suggest that incorporating them in the gravity description requires the introduction of new, lighter and lighter, fields in the bulk with fluctuating boundary couplings

Multi-trace Correlators in the SYK Model and Non-geometric Wormholes

We study the Lyapunov exponent $\lambda_L$ in quantum field theories with spacetime-independent disorder interactions. Generically $\lambda_L$ can only be computed at isolated points in parameter space, and little is known about the way in which chaos grows as we deform the theory away from weak coupling. In this paper we describe families of theories in which the disorder coupling is an exactly marginal deformation, allowing us to follow $\lambda_L$ from weak to strong coupling. We find surprising behaviors in some cases, including a discontinuous transition into chaos. We also derive self-consistency equations for the two- and four-point functions for products of $N$ nontrivial CFTs deformed by disorder at leading order in $1/N$.

The onset of quantum chaos in disordered CFTs

We suggest a model of the large N limit ${\cal N}=4$ D=4 SU(N) SYM as a gas of 3-branes in a 10 dimensional space. Field theory analysis suggests that this 10 dimensional space does not carry the usual gravity dynamics but rather a contraction of it. Using a non-local transformation some aspects of the dynamics of this system are mapped to the dynamics of standard gravitons on $AdS_5\times S^5$. In particular some of the correspondence between operator in the CFT and states on $AdS$ is more transparent.

Micha Berkooz

Papers

Multi-trace Correlators in the SYK Model and Non-geometric Wormholes

The onset of quantum chaos in disordered CFTs

A Proposal on Some Microscopic Aspects of the AdS/CFT Duality