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Gauge Fields, Strings and Gravity

Final Report Summary - HOLOGRAPHY (Gauge fields, strings and gravity)

Two central problems in modern theoretical high energy physics are:
(a) the problem of obtaining an analytic formulation of the strong coupling dynamics of asymptotically free gauge theories (e.g. in quantum chromodynamics (QCD)), and
(b) the problem of understanding the dynamics of gravity in the vicinity of spacetime singularities (e.g. black holes or cosmological singularities).
The present project aims to make progress in both of these problems with a parallel study of D-brane dynamics in string theory and black holes in gravity.

More specifically, two major goals were set:
(i) to engineer QCD-like gauge theories in open string theory (special emphasis was given to D-brane dynamics in non-critical string theory backgrounds and non-supersymmetric situations), to explore the implications of such descriptions on the strong coupling dynamics of these theories, and to develop new techniques in the general context of the AdS/CFT correspondence,
(ii) to develop a systematic description of black hole statics and dynamics in higher dimensional gravity, e.g. to establish new horizon topologies.

Work was performed in parallel stages in both directions and was carried out in separate individual projects led by the researcher alone and by the researcher in collaboration with two different groups of scientists from different universities in England, Israel, France, Spain, Denmark and Sweden.

In part (i) of the planned research work, a major result was obtained early on in collaboration with Adi Armoni, Dan Israel and Gregory Moraitis. With a combination of string and field theory methods we found strong evidence for Seiberg duality and exact conformal windows in 4D non-supersymmetric QCD-like gauge theories at finite-N. This is a very rare instance where the exact conformal window of a 4D non-supersymmetric gauge theory can be determined exactly. It is also a rare instance where a Seiberg duality is proposed for a non-supersymmetric gauge theory.

Additional work was performed in the context of 3D Chern-Simons-Matter quantum field theories. Recent developments have demonstrated that these theories are relevant for the dynamics of M2-branes in string/M theory and for a set of very interesting examples of the AdS4/CFT3 correspondence. Our work has uncovered new Seiberg-like dualities in a large class of such theories. Beyond the formulation of new examples of Seiberg duality in 3D conformal field theory this work illustrates vividly the fascinating wealth of quantum field theory dynamics in three dimensions.

Work was also performed in the context of the AdS/CFT correspondence. In Fortsch. Phys. 57:646-653, 2009 results were reported based on work with Elias Kiritsis on the subject of the multi-AdS/multi-CFT correspondence. This work addresses a well-known problem -the non-perturbative consistency of theories with massive (multi)gravity- in the context of the AdS/CFT correspondence. Some of the main tools developed in this work are also relevant for the implementation of the replica trick in AdS/CFT discussions of disorder and glassy physics, where we anticipate that they will find interesting applications.

Finally, we have initiated a systematic effort to develop a new effective field theory tool for the description of flavour dynamics in the quenched approximation in holographic QCD.

Regarding part (ii) of the planned research work, we developed a new powerful tool that captures efficiently many of the qualitatively new properties of black holes in higher dimensions. These properties include new stationary phases with exotic horizon geometries, critical phenomena and horizon topology-changing transitions. A whole new line of research is opening up with these developments and previously inaccessible aspects of higher dimensional gravity are now within reach. Besides a better understanding of gravity, this work has potential applications in AdS/CFT and the subject of black holes/branes in string theory.