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arXiv · hep-th/0204120

Non-BPS Brane Cosmology

Ph. Brax·D. A. Steer
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Abstract

We study cosmology on a BPS D3-brane evolving in the 10D SUGRA background describing a non-BPS brane. Initially the BPS brane is taken to be a probe whose dynamics we determine in the non-compact non-BPS background. The cosmology observed on the brane is of the FRW type with a scale factor $S(τ)$. In this mirage cosmology approach, there is no self-gravity on the brane which cannot inflate. Self-gravity is then included by compactifying the background space-time. The low energy effective theory below the compactification scale is shown to be bi-metric, with matter coupling to a different metric than the geometrically induced metric on the brane. The geometrical scale factor on the brane is now $S(τ) a(τ)$ where $a(τ)$ arises from brane self-gravity. In this non-BPS scenario the brane generically inflates. We study the resulting inflationary scenario taking into account the fact that the non-BPS brane eventually decays on a time-scale much larger than the typical inflationary time-scale. After the decay, the theory ceases to be bi-metric and COBE normalization is used to estimate the string scale which is found to be of order $10^{14}$ GeV.

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Ph. Brax, D. A. Steer. 2002-04-15. Non-BPS Brane Cosmology. https://doi.org/10.1088/1126-6708%2F2002%2F05%2F016

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