Mon, 11 Feb 2013

12:00 - 13:00
L3

On sequestering and decoupling in stabilized string models

David Marsh
(Oxford)
Abstract
I will describe recent efforts to understand the mediation of supersymmetry breaking in stabilized compactifications of type IIB string theory. By geometrically separating the visible sector from the supersymmetry breaking effects one may hope to achieve sequestered supersymmetry breaking and much ameliorated constraints from bounds on flavor changing neutral currents. However, in this talk I will discuss how non-perturbative superpotential cross-couplings between the visible sector and the Kähler moduli may spoil sequestering and introduce a sensitivity to the global details of the compactification. As a simple example, I will describe the structure of these `de-sequestering’ operators for a class of visible sectors realized by D-branes probing an orbifold singularity, and I will discuss their importance in the KKLT and LVS moduli stabilization scenarios.
Mon, 14 Jan 2013

12:00 - 13:00
L3

Non-commuting closed strings on non-geometric backgrounds

Magdalena Larfors
(Oxford)
Abstract
Strings are extended objects, and this means that they can be compactified not only on Riemannian manifolds, but also on more exotic spaces with generalized transition functions. An example of this is the T-fold, where T-duality is used to glue the Neveu-Schwarz fields of the background. Collectively, these exotic set-ups are known as non-geometric string compactifications, and in this talk I will discuss two of their aspects. First, I will present a field redefinition in the Neveu-Schwarz sector that allows a ten-dimensional, effective description of certain non-geometric backgrounds. This redefinition is inspired by Generalized Geometry and Double Field Theory. Second, I will show that closed strings become non-commuting when non-geometric fluxes are turned on. This will be done through the analysis of a three-torus with H-flux and its T-dual configurations.
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