Mon, 09 Feb 2009

12:00 - 13:00
L3

Topology changing T-dualities

Jarah Evslin
(SISSA)
Abstract
We define an action of ordinary and Narain T-duality on an arbitrary torus bundle by applying Buscher and Narain's formulations patchwise. In general it changes the topology of the compactification manifold and its NS 3-form flux, for example in the case of a circle bundle it interchanges the Chern class with a pushforward of the flux. It nonetheless provides a candidate duality of the full string theory because it preserves several topological and geometric invariants such as the twisted K-theory in type II and the tadpole and supersymmetry conditions in non-Kahler heterotic compactifications.
Mon, 02 Feb 2009

17:00 - 18:00
Gibson 1st Floor SR

Existence of conformal metric with constant Q-curvature

Andrea Malchiodi
(SISSA)
Abstract
A classical problem in differential geometry is to deform the metric of a given manifold so that some of its curvatures become prescribed functions. Classical examples are the Uniformization problem for compact surfaces and the Yamabe problem for compact manifolds of dimension greater than two.
We address a similar problem for the so-called Q-curvature, which plays an important role in conformal geometry and is a natural higher order analogue of the Gauss curvature. The problem is tackled using a variational and Morse theoretical approach.
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