197 research outputs found
On Relativistic Brane Probes in Singular Spacetimes
We study the relativistic dynamics of brane probes in singular warped
spacetimes and establish limits for such analysis. The behavior of the
semiclassical brane probe wave functions implies that unitarity boundary
conditions can be imposed at the singularity.Comment: 9 pages, 1 figure, typos corrected and references adde
Exponential Hierarchy From Spacetime Variable String Vacua
It is shown that non-supersymmetric spacetime varying string vacua can lead
to an exponential hierarchy between the electroweak and the gravitational
scales. The hierarchy is naturally generated by a string coupling of O(1).Comment: 22 pages, Latex, 2 figure
Probing Naked Singularities in Non-supersymmetric String Vacua
We present a detailed analysis of non-supersymmetric spacetime varying string
vacua which can lead to an exponential hierarchy between the electroweak and
the gravitational scales. In particular, we identify a limit in which these
vacua can be interpreted as supersymmetric vacua of F-theory. Furthermore, we
study the properties of these solutions as seen by -brane probes and
establish a non-supersymmetric analogue of the enhancon mechanism.Comment: 46 pages, Latex, 7 figures; the brane probe analysis (sections 3 and
4) has been revised, references added and typos correcte
On the Geometry and Homology of Certain Simple Stratified Varieties
We study certain mild degenerations of algebraic varieties which appear in
the analysis of a large class of supersymmetric theories, including superstring
theory. We analyze Witten's sigma-model and find that the non-transversality of
the superpotential induces a singularization and stratification of the ground
state variety. This stratified variety (the union of the singular ground state
variety and its exo-curve strata) admit homology groups which, excepting the
middle dimension, satisfy the "Kahler package" of requirements, extend the
"flopped" pair of small resolutions to an "(exo)flopped" triple, and is
compatible with mirror symmetry and string theory. Finally, we revisit the
conifold transition as it applies to our formalism.Comment: LaTeX 2e, 18 pages, 4 figure
- …