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arXiv · hep-th/0207214

On Time-dependent Backgrounds in Supergravity and String Theory

Alex Buchel·Peter Langfelder·Johannes Walcher
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Abstract

Time-dependent solutions of supergravity and string theory are studied. The examples are obtained from de Sitter deformation of gauge/gravity dualities, analytical continuation of static solutions, and ``exactly solvable'' worldsheet models. Among other things, it is shown that turning on a Hubble parameter in the background of a confining gauge theory in four dimensions can restore chiral symmetry. Some of the solutions obtained from analytical continuation have the interpretation of a universe with a bounce separating a big bang from a big crunch singularity. In the worldsheet context, it is argued why string propagation close to a Milne-type cosmological singularity might be physically non-singular.

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Alex Buchel, Peter Langfelder, Johannes Walcher. 2002-08-13. On Time-dependent Backgrounds in Supergravity and String Theory. https://doi.org/10.1103/physrevd.67.024011

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