9,961 research outputs found
Arguments for F-theory
After a brief review of string and -Theory we point out some deficiencies.
Partly to cure them, we present several arguments for ``-Theory'', enlarging
spacetime to signature, following the original suggestion of C. Vafa.
We introduce a suggestive Supersymmetric 27-plet of particles, associated to
the exceptional symmetric hermitian space . Several
possible future directions, including using projective rather than metric
geometry, are mentioned. We should emphasize that -Theory is yet just a very
provisional attempt, lacking clear dynamical principles.Comment: To appear in early 2006 in Mod. Phys. Lett. A as Brief Revie
Aspects of F-Theory GUTs
The basic tools for model building in F-theory are reviewed and applied to
the construction of SU(5) models. The flux mechanism for gauge symmetry
breaking and doublet triplet splitting is analysed. A short account for the
gauge coupling unification and the role of flux and Kaluza-Klein thresholds is
also given.Comment: 37 pages. Based on Talk presented at Corfu 2011 Workshop "Fields and
Strings: Theory - Cosmology - Phenomenology. September 14 - 18, 2011".
(Prepared for the proceedings
Axion Inflation in F-theory
We study the dynamics of axion-like fields in F-theory and suggest that they
can serve as inflatons in models of natural inflation. The axions arise from
harmonic three-forms on the F-theory compactification space and parameterize a
complex torus that varies over the geometric moduli space. In particular, this
implies that the axion decay constants depend on the complex structure moduli
that can be fixed by background fluxes. This might allow tuning them to be
super-Planckian in a controlled way and allow for interesting single field
inflationary models. We argue that this requires a localization of the
three-forms near regions of strong string coupling, analogously to the
reasoning that GUT physics requires the use of F-theory. These models can admit
a tensor to scalar ratio r>0.1.Comment: 9 pages, 1 figure; v2: added clarifying remarks and reference
Phenomenological Aspects of F-theory
Stabilizing a heterotic string vacuum with a large expectation value of the
dilaton and simultaneously breaking low-energy supersymmetry is a long-standing
problem of string phenomenology. We reconsider these issues in light of the
recent developments in F-theory.Comment: 11 pages, phyzzx macro
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