Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: D7-Brane Motion from M-Theory Cycles and Obstructions in the Weak
  Coupling Limit   Motivated by the desire to do proper model building with D7-branes and
fluxes, we study the motion of D7-branes on a Calabi-Yau orientifold from the
perspective of F-theory. We consider this approach promising since, by working
effectively with an elliptically fibred M-theory compactification, the explicit
positioning of D7-branes by (M-theory) fluxes is straightforward. The locations
of D7-branes are encoded in the periods of certain M-theory cycles, which
allows for a very explicit understanding of the moduli space of D7-brane
motion. The picture of moving D7-branes on a fixed underlying space relies on
negligible backreaction, which can be ensured in Sen's weak coupling limit.
However, even in this limit we find certain 'physics obstructions' which reduce
the freedom of the D7-brane motion as compared to the motion of holomorphic
submanifolds in the orientifold background. These obstructions originate in the
intersections of D7-branes and O7-planes, where the type IIB coupling can not
remain weak. We illustrate this effect for D7-brane models on CP^1 x CP^1 (the
Bianchi-Sagnotti-Gimon-Polchinski model) and on CP^2. Furthermore, in the
simple example of 16 D7-branes and 4 O7-planes on CP^1 (F-theory on K3), we
obtain a completely explicit parameterization of the moduli space in terms of
periods of integral M-theory cycles. In the weak coupling limit, D7-brane
motion factorizes from the geometric deformations of the base space.

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The categories of this paper are: cond-mat
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph