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

Large N Field Theories, String Theory and Gravity

A holographic derivation of the entanglement entropy in quantum (conformal) field theories is proposed from anti-de Sitter/conformal field theory (AdS/CFT) correspondence. We argue that the entanglement entropy in d + 1 dimensional conformal field theories can be obtained from the area of d dimensional minimal surfaces in AdS(d+2), analogous to the Bekenstein-Hawking formula for black hole entropy. We show that our proposal agrees perfectly with the entanglement entropy in 2D CFT when applied to AdS(3). We also compare the entropy computed in AdS(5)XS(5) with that of the free N=4 super Yang-Mills theory.

Holographic Derivation of Entanglement Entropy from the anti de Sitter Space/Conformal Field Theory Correspondence

We outline the construction of metastable de Sitter vacua of type IIB string theory. Our starting point is highly warped IIB compactifications with nontrivial NS and RR three-form fluxes. By incorporating known corrections to the superpotential from Euclidean D-brane instantons or gaugino condensation, one can make models with all moduli fixed, yielding a supersymmetric AdS vacuum. Inclusion of a small number of $\overline{\mathrm{D}3}$-branes in the resulting warped geometry allows one to uplift the AdS minimum and make it a metastable de Sitter ground state. The lifetime of our metastable de Sitter vacua is much greater than the cosmological time scale of ${10}^{10}\mathrm{yr}.$ We also prove, under certain conditions, that the lifetime of dS space in string theory will always be shorter than the recurrence time.

/pdf/de-sitter-vacua-in-string-theory-2gp3ty8kg8.pdf

De Sitter vacua in string theory

We compute the three point correlation functions for primordial scalar and tensor fluctuations in single field inflationary models We obtain explicit expressions in the slow roll limit where the answer is given terms of the two usual slow roll parameters In a particular limit the three point functions are determined completely by the tilt of the spectrum of the two point functions We also make some remarks on the relation of this computation to dS/CFT and AdS/CFT We emphasize that (A)dS/CFT can be viewed as a statement about the wavefunction of the universe

https://iopscience.iop.org/article/10.1088/1126-6708/2003/05/013/pdf

Non-Gaussian features of primordial fluctuations in single field inflationary models

The first part is an introduction to conformal field theory and string perturbation theory. The second part deals with the search for a deeper answer to the question posed in the title. Contents: 
1. Conformal Field Theory 
2. String Theory 
3. Vacua and Dualities 
4. String Field Theory or Not String Field Theory 
5. Matrix Models

https://arxiv.org/pdf/hep-th/9411028v1.pdf

What is string theory

We discuss the emergence of $ \mathcal{W} \mbox{-algebras}$
 as asymptotic symmetries of higher-spin gauge theories coupled to three-dimensional Einstein gravity with a negative cosmological constant. We focus on models involving a finite number of bosonic higher-spin fields, and especially on the example provided by the coupling of a spin-3 field to gravity. It is described by a SL(3) × SL(3) Chern-Simons theory and its asymptotic symmetry algebra is given by two copies of the classical $ {\mathcal{W}_3}\mbox{-algebra} $
 with central charge the one computed by Brown and Henneaux in pure gravity with negative cosmological constant.

/pdf/asymptotic-symmetries-of-three-dimensional-gravity-coupled-4x4zwo0492.pdf

Asymptotic symmetries of three-dimensional gravity coupled to higher-spin fields

Wilson-Polyakov loop at finite temperature in large- N gauge theory and anti-de Sitter supergravity

http://cds.cern.ch/record/271683/files/th-7495-94.pdf

Simple singularities and N = 2 supersymmetric Yang-Mills theory

Mirror Symmetry, Picard-Fuchs equations and instanton corrected Yukawa couplings are discussed within the framework of toric geometry. It allows to establish mirror symmetry of Calabi-Yau spaces for which the mirror manifold had been unavailable in previous constructions. Mirror maps and Yukawa couplings are explicitly given for several examples with two and three moduli.

/pdf/mirror-symmetry-mirror-map-and-applications-to-calabi-yau-2eq4ztnxd5.pdf

Mirror Symmetry, Mirror Map and Applications to Calabi-Yau Hypersurfaces

We present a first step towards generalizing the work of Seiberg and Witten on N=2 supersymmetric Yang-Mills theory to arbitrary gauge groups. Specifically, we propose a particular sequence of hyperelliptic genus $n-1$ Riemann surfaces to underly the quantum moduli space of $SU(n)$ N=2 supersymmetric gauge theory. These curves have an obvious generalization to arbitrary simply laced gauge groups, which involves the A-D-E type simple singularities. To support our proposal, we argue that the monodromy in the semiclassical regime is correctly reproduced. We also give some remarks on a possible relation to string theory.

/pdf/simple-singularities-and-n-2-supersymmetric-yang-mills-1sv7qploo8.pdf

Stefan Theisen

Papers

Asymptotic symmetries of three-dimensional gravity coupled to higher-spin fields

Wilson-Polyakov loop at finite temperature in large- N gauge theory and anti-de Sitter supergravity

Simple singularities and N = 2 supersymmetric Yang-Mills theory

Mirror Symmetry, Mirror Map and Applications to Calabi-Yau Hypersurfaces

Simple Singularities and N=2 Supersymmetric Yang-Mills Theory