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Bps Brane Cosmology In N=2 Supergravity, Moataz Emam Aug 2015

Bps Brane Cosmology In N=2 Supergravity, Moataz Emam

Moataz Emam

We study the embedding of flat BPS 3-branes in five dimensional N=2 supergravity theory. We derive the branes' dynamical equations as well as general expressions for the hypermultiplet fields then focus on a single brane and study its time evolution. It is shown that the brane's Hubble parameter correlates with the moduli of the underlying manifold's complex structure. For certain particular solutions, the moduli seem to exhibit an instability; being large valued at early times then rapidly decaying to either zero or some convergent constant value. The possibility of extending these results to the cosmology of our universe is implied …

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Bps One-Branes In Five Dimensions, Moataz Emam Jan 2013

Bps One-Branes In Five Dimensions, Moataz Emam

Moataz Emam

In a recent paper, we studied the scalar fields of the five dimensional N=2 hypermultiplets using the method of symplectic covariance. For static spherically symmetric backgrounds, we showed that exactly two possibilities exist and detailed one of them. In this paper, we present the second case: Bogomol'nyi-Prasad-Sommerfield (BPS) one-branes carrying charge under the hypermultiplets. We find an explicitly symplectic solution of the fields in this background and derive the conditions required for a full spacetime understanding.

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The Five Dimensional Universal Hypermultiplet And The Cosmological Constant Problem, Moataz Emam, Charles Canestaro Jan 2013

The Five Dimensional Universal Hypermultiplet And The Cosmological Constant Problem, Moataz Emam, Charles Canestaro

Moataz Emam

We model the universe as a 3-brane embedded in five dimensional spacetime with N=2 supersymmetry. The presence of the scalar fields of the universal hypermultiplet in the bulk results in a positive pressure effectively reducing the value of the cosmological constant and thereby providing a possible answer as to why the measured value of the cosmological constant is many orders of magnitude smaller than predicted from the vacuum energy. The solution allows for any number of parallel branes to exist and relates their cosmological constants (as well as matter densities and radiation pressures) to the value of the dilaton in …

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Split-Complex Representation Of The Universal Hypermultiplet, Moataz Emam Jan 2011

Split-Complex Representation Of The Universal Hypermultiplet, Moataz Emam

Moataz Emam

Split-complex fields usually appear in the context of Euclidean supersymmetry. In this paper, we propose that this can be generalized to the non-Euclidean case and that, in fact, the split-complex representation may be the most natural way to formulate the scalar fields of the five dimensional universal hypermultiplet. We supplement earlier evidence of this by studying a specific class of solutions and explicitly showing that it seems to favor this formulation. We also argue that this is directly related to the symplectic structure of the general hypermultiplet fields arising from non-trivial Calabi-Yau moduli. As part of the argument, we find …

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Are We There Yet? The Search For A Theory Of Everything, Moataz Emam Jan 2011