Abstract
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 cannot remain weak. We illustrate this effect for D7-brane models on CP 1 × 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.
Highlights
Significant progress has been made in the understanding of stringtheoretic inflation, moduli stabilization, supersymmetry breaking and the fine tuning of the cosmological constant using the flux discretuum
This is a non-trivial task since the underlying Calabi– Yau geometry has to be sufficiently complicated to allow for the necessary enormous fine tuning of the cosmological constant mentioned above
Our main points in this article were the implications of the weak coupling limit and the description of D7-brane motion on CP1 in terms of integral M-theory cycles
Summary
Significant progress has been made in the understanding of stringtheoretic inflation, moduli stabilization, supersymmetry breaking and the fine tuning of the cosmological constant using the flux discretuum. We are able to express these 2-cycles in terms of the standard integral homology basis of K3 This situation corresponds to a base space with the shape of a pillowcase (i.e. T 2/Z2) with one O-plane and four D-branes at each corner. Our new point is the explicit mapping between the periods and certain geometrically intuitive 2-cycles and, the mapping between those 2-cycles and the standard integral homology basis of K3 We believe that this will be crucial for the future study of brane stabilization by fluxes (since those are quantized in terms of the corresponding integral cohomology) and for the generalization to higher-dimensional situations. We end with a brief section describing our conclusions and perspectives on future work
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
