SÉMINAIRE DU GRECO
"Classical de Sitter string backgrounds" |
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David Andriot |
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Realising cosmological models in string theory, by for instance embedding inflation models in a string compactification, typically requires to have a metastable de Sitter background. The latter would correspond to e.g. the vacuum at the end of inflation. Here we focus on classical backgrounds: those only contain well-controlled ingredients to realise the embedding as a compactification. Such de Sitter solutions are very difficult to obtain, and there exists so far no metastable example. We study this problem and as a first step, we derive new constraints on the existence of classical de Sitter solutions, considering various configurations of D-branes and orientifolds. While some configurations completely forbid having de Sitter solutions, others still allow for it in small regions of the parameter space that we identify. |
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lundi 9 octobre 2017 - 11:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris |
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