567 research outputs found
ADE String Chains and Mirror Symmetry
6d superconformal field theories (SCFTs) are the SCFTs in the highest
possible dimension. They can be geometrically engineered in F-theory by
compactifying on non-compact elliptic Calabi-Yau manifolds. In this paper we
focus on the class of SCFTs whose base geometry is determined by curves
intersecting according to ADE Dynkin diagrams and derive the corresponding
mirror Calabi-Yau manifold. The mirror geometry is uniquely determined in terms
of the mirror curve which has also an interpretation in terms of the
Seiberg-Witten curve of the four-dimensional theory arising from torus
compactification. Adding the affine node of the ADE quiver to the base
geometry, we connect to recent results on SYZ mirror symmetry for the case
and provide a physical interpretation in terms of little string theory. Our
results, however, go beyond this case as our construction naturally covers the
and cases as well.Comment: version 2: typos corrected, 30 pages, 8 figure
No-Go Theorems on Localization of Gravity around Higher Codimensional Branes in Noncompact Extra Dimensions
We study the brane world scenario of a single brane (or a single stack of
branes) with codimension higher than one. When the extra dimensions are not
small, localization of gravity around the brane is needed in order to reproduce
the observable four-dimensional gravity. We focus on the case of noncompact
extra dimensions, where the possibility of localized gravity becomes
non-trivial. We show that in large class of gravity models, localization of
massless gravity is not possible for codimension-2 branes with at least one
noncompact extra dimension. With additional mild assumptions on field
backgrounds, we also show that it is not possible for higher codimensional
branes with two or more noncompact extra dimensions.Comment: 23 pages, published version in JHE
Large U(1) charges from flux breaking in 4D F-theory models
We study the massless charged spectrum of U(1) gauge fields in F-theory that
arise from flux breaking of a nonabelian group. The U(1) charges that arise in
this way can be very large. In particular, using vertical flux breaking, we
construct an explicit 4D F-theory model with a U(1) decoupled from other gauge
sectors, in which the massless/light fields have charges as large as 657. This
result greatly exceeds prior results in the literature. We argue heuristically
that this result may provide an upper bound on charges for light fields under
decoupled U(1) factors in the F-theory landscape. We also show that the charges
can be even larger when the U(1) is coupled to other gauge groups.Comment: 29 pages, 1 figur
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