M-theory is the nonperturbative description of string theory. Within M-theory there exist two sorts of extended object, the membrane and the five-brane. These objects self-interact and interact with each other. The goal of the research of David Berman here is to study these interactions so as to throw light on the mysteries of M-theory. In particular in recent years he has been looking at how open membranes end on five-branes this being the M-theory analogue of how fundamental strings end on D-branes. The techniques used have included: calculating scattering amplitudes of brane intersections; looking for world volume solutions; using fuzzy funnel descriptions; calculating anomalies; and searching for relevant supergravity solutions.
Andreas Brandhuber's main research interests are centered around string theory, supersymmetric gauge theories and their interrelations. Exciting advances in these fields have recently come about due to the realisation that certain field theories are dual to certain string theories. This discovery has led to major progress in our understanding of the dynamics of gauge theories at the perturbative and non-perturbative level. In the last years his research has been devoted to exploring theoretical scenarios where the interplay between string and field theory has proved to be particularly fruitful and productive:
- The novel duality between N=4 super Yang-Mills and twistor string theory, and its applications.
- The study of the non-perturbative dynamics of supersymmetric gauge theories using exactly calculable anomalies, branes in string theory and dualities.
- M-theory compactifications on G_2 manifolds and their implications for model building.
- The AdS/CFT correspondence and its generalisations to non-conformal gauge theories.
Costis Papageorgakis is interested in the study of D-brane and M-brane dynamics, in string and M-theory respectively, as well as their associated supersymmetric gauge theories. In the past he has worked towards understanding multiple M2-branes in terms of superconformal Chern-Simons-matter theory in 3d. Costis' current research focusses on the low-energy description of multiple M5-branes through the superconformal (2,0) theory in 6d. This can be tackled via lower-dimensional theories: 5d super Yang-Mills as well as 4d circular quiver gauge theories, with the latter viewed in the context of dimensional deconstruction. A range of approaches and techniques can be employed for that purpose, including exact methods in the study of the full non-perturbative dynamics and revisiting the role of soliton contributions to perturbative amplitudes.
Sanjaye Ramgoolam works on various aspects of String/M-Theory. Gauge-string duality is a dominant theme. Specific examples studied include topological strings/2d-Yang-Mills, M-theory/Matrix-Theory, AdS/CFT. Other topics of interest are fuzzy spaces, time-dependent D-branes, black holes, cosmology, and particle physics. His work interfaces with mathematical topics such as quantum groups, non-commutative geometry, Hecke algebras, and Schur-Weyl duality.
Rodolfo Russo's research interests are centered on String Theory, with particular attention to its relation with gauge theories and particle physics. The lines of his current research include: string perturbation theory, particularly its applications to phenomenological string models such as the Intersecting Brane Worlds, and formal developments on multi-loop amplitudes; gauge/string dualities, in particular the relation between strings on AdS5 x S5 and N=4 super Yang-Mills and its non-conformal extensions; supersymmetric gauge theories and their realization by means of D-branes.
Bill Spence researches in M-theory and string theory and related areas of mathematics. Particular areas of past interest have been the geometry of branes in M-theory, topological field theories, and manifolds of exceptional holonomy. During 2005-2007 he worked on a new theory called twistor string theory, proving that the twistor-inspired approach to gauge theories can be applied at the quantum level. In the past few years he has been working on the new Wilson loop approach to gauge theories and gravity, as well as other new developments in the study of amplitudes in quantum field theories and string theory.
In the past Steve Thomas has worked on orbifold compactifiactions of Heterotic superstrings and also heterotic M-theory compactifications and their phenomenological applications to particle physics. His interests have also included applications of Conformal Field Theories in condensed matter systems and so called 'conformal turbulence' in two dimensions. More recently his interests have widened to include fuzzy geometries, D-brane dynamics in curved backgrounds, unstable D-branes/Tachyon condensation and string/D-brane inspired Cosmologies.
Over the past years, Gabriele Travaglini's research has focused on the following themes:
- the study of the rich mathematical structure of perturbative scattering amplitudes in gauge theory and gravity, particularly using twistor-inspired methods and the amplitude/Wilson loop duality;
- nonperturbative effects (e.g. instantons) in supersymmetric gauge theories;
- the application of noncommutative geometry to particle physics;
- the AdS/CFT and the PP-wave/N=4 super Yang-Mills correspondence.
The unifying theme of these topics is perhaps the existence of deep connections between gauge theory and string theory. String/field theory dualities are one of the most fascinating discoveries in modern theoretical physics, and represent a powerfool tool for deepening our understanding of the dynamics of both gauge theory, gravity, and superstrings.
Brian Wecht's research has spanned a number of different topics throughout high energy theory. Much of his work focused particularly on four-dimensional superconformal field theories from both the field theory and string theory points of view. Brian Wecht has also worked on string theory in its own right, in particular studying the so-called non-geometric compactifications, expanding the set of possible four-dimensional string vacua considerably via their use. During the past several years, he has also been working on gauge mediation of supersymmetry breaking, and with N. Seiberg and T. Volansky discovered a new framework for mediating supersymmetry breaking to the Standard Model. Finally, Brian Wecht is also interested in exploring scattering amplitudes, particularly from a string theory perspective.
Donovan Young's research interests focus on correlation functions, Wilson loops and scattering amplitudes in the AdS/CFT correspondence. He has worked extensively on higher-loop computations in quantum field theory, as well as on supergravity and string theory calculations on the string side of the correspondence.