Friday's
Organizers: S. Vandoren, B. de Wit, E. Looijenga, J. Stienstra
 

Joint Mathematics-Physics Seminar abstract

A. Dancer ( Oxford, U.K. ) and M. Zabzine ( Uppsala, Sweden ) - 27 February 2009

Ricci sollitons with large symmetry group and Generalized geometry and chiral de Rham complex

C. Schweigert (Univ. of Hamburg) - 23 May 2008

Bundle gerbes and surface holonomy

Hermitian bundle gerbes are the appropriate geometric framework for Wess-Zumino terms entering the Lagrangian description of certain two-dimensional quantum field theories. We introduce algebraic notions for Hermitian bundle gerbes, including Jandl structures, gerbe modules and gerbe bimodules. We show how they arise in the description of such theories on unoriented surfaces, surfaces with boundaries and surfaces with defect lines, respectively.

L. Hollands (UvA) - 7 December 2007

Topological strings as D-modules

slides of the talk

Following arxiv:0709.4446 I'll describe a chain of string dualities relating the counting of Donaldson-Thomas invariants on a large class of non-compact Calabi-Yau threefolds to four-dimensional supersymmetric gauge theories and to free fermions in two dimensional intersecting brane systems with a B-field turned on, which may be mathematically described as D-modules.

V. Cortes (Univ. Hamburg) - 13 April 2007

Cones over pseudo-Riemannian manifolds

By a classical theorem of Gallot (1979), a Riemannian cone over a complete Riemannian manifold is either flat or has irreducible holonomy. We consider metric cones with reducible holonomy over pseudo-Riemannian manifolds and obtain local and global structure theorems.

(This is joint work in progress with Dmitri Alekseevsky, Thomas Leistner and Anton Galaev.)

J. Stienstra (UU) - 13 April 2007

Geometric structures related to AdS/CFT

I will discuss connections (found in physics papers) between Sasaki-Einstein 5-folds on the one hand and quivers on the other hand.
This will also involve intrigueing viewpoints on zero loci of 2-variable Laurent polynomials.


V. Mathai (University of Adelaide) - 24 November 2006

T-duality in a background H-flux

This talk will be concerned with global aspects of T-duality on compactified spacetimes that are torus bundles, in the presence of a topologically nontrivial background H-flux. The characterization of when exactly the T-dual is another torus bundle with H-flux will be discussed. Global, nonclassical spacetimes will be proposed in the other cases, and justified. Finally, the current status of this theory will be outlined.

S. Vandoren (UU) - 3 February 2006

Quaternionic manifolds from special Kahler geometry

Special Kahler, hyper-Kahler and Quaternionic-Kahler geometries play an important role in theories with supersymmetry, in particular in string theory and supergravity. Mathematically, these manifolds appear as moduli spaces of Calabi-Yau threefolds. In this talk, we review some aspects of these geometries, and show how one can construct a class of Quaternionic-Kahler spaces from Special Kahler spaces, using a map that physicist call "the c-map".

L. Hoevenaars (UU) - 3 February 2006

Special Kahler geometry and Frobenius manifolds

Frobenius manifolds are a way to describe families of 2-dimensional topological field theories, characterized by a single holomorphic function satisfying the Witten-Dijkgraaf-Verlinde-Verlinde
(WDVV) equations. On the other hand, 4-dimensional gauge theories with
N=2 supersymmetry can be described using special Kahler manifolds, also associated with a holomorphic function which sometimes satisfies the WDVV equations and are thereby almost Frobenius manifolds. In this talk, after introducing the notions above we will explain their relation following a paper by Dubrovin on almost duality of Frobenius manifolds.