Past Quantum Field Theory Seminar

10 June 2014
12:00
John Barrett (Nottingham)
Abstract
The talk will give a definition of matrix geometries, which are particular types of finite real spectral triple that are useful for approximating manifolds. Examples include fuzzy spheres and also the internal space of the standard model. If time permits, the relation of matrix geometries with 2d state sum models will also be sketched.
  • Quantum Field Theory Seminar
29 April 2014
12:00
Stefan Hollands (Leipzig)
Abstract
Quantum field theory (QFT) originated in physics in the context of elementary particles. Although, over the years, surprising and profound connections to very diverse branches of mathematics have been discovered, QFT does not have, as yet, found a universally accepted "standard" mathematical formulation. In this talk, I shall outline an approach to QFT that emphasizes its underlying algebraic structure. Concretely, this is represented by a concept called "Operator Product Expansion". I explain the properties of such expansions, how they can be constructed in concrete QFT models, and the emergent relationship between "perturbation theory" on the physics side and "Hochschild cohomology" on the physics side. This talk is based on joint work with Ch. Kopper and J. Holland from Ecole Polytechnique, Paris.
  • Quantum Field Theory Seminar
19 March 2014
12:00
to
13:30
Daniel Sudarsky (National Autonomous University of Mexico)
Abstract
The observations of the first traces of cosmic structure in the Cosmic Microwave Background are in excellent agreement with the predictions of Inflation. However as we shall see, that account is not fully satisfactory, as it does not address the transition from an homogeneous and isotropic early stage to a latter one lacking those symmetries. We will argue that new physics along the lines of the dynamical quantum state reduction theories is needed to account for such transition and, motivated by Penrose's ideas suggest that quantum gravity might be the place from where this new physics emerges. Moreover we will show that observations can be used to constrain the various phenomenological proposals made in this regard.
  • Quantum Field Theory Seminar
4 February 2014
12:00
to
13:30
Shahn Majid (Queen Mary and Oxford)
Abstract
The talk is based on my paper with E. Beggs appearing in Class. Quantum Gravity. Working within a bimodule approach to noncommutative geometry, we show that even a small amount of noncommutativity drastically constrains the moduli space of noncommutative metrics. In particular, the algebra [x,t]=x is forced to have a geometry corresponding to a gravitational source at x=0 so strong that even light cannot escape. This provides a non-trivial example of noncommutative Riemannian geometry and also serves as an introduction to some general results.
  • Quantum Field Theory Seminar
21 January 2014
12:00
to
13:30
Mathew Pugh (Cardiff)
Abstract
The modular invariant partition functions for SU(2) and SU(3) conformal field theories have been classified. The SU(2) theory is closely related to the preprojective algebras of Coxeter-Dynkin quivers. The analogous finite dimensional superpotential algebras, which we call almost Calabi-Yau algebras, associated to the SU(3) invariants will be discussed.
  • Quantum Field Theory Seminar

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