Comments on Cosmological Singularities in String Theory

By M. Berkooz, Ben Craps, D. Kutasov, G. Rajesh. 2002

144 citations recorded by the source corpus.

We compute string scattering amplitudes in an orbifold of Minkowski space by a boost, and show how certain divergences in the four point function are associated with graviton exchange near the singularity. These divergences reflect large tree-level backreaction of the gravitational field. Near the singularity, all excitations behave like massless fields on a 1+1 dimensional cylinder. For excitations that are chiral near the singularity, we show that divergences are avoided and that the backreaction is milder. We discuss the implications of this for some cosmological spacetimes. Finally, in order to gain some intuition about what happens when backreaction is taken into account, we study an open string rolling tachyon background as a toy model that shares some features with R^{1,1}/Z.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/070b46ee15604c03c6c6eb94c3883cc9e37db727

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Citations in the corpus

Ekpyrotic and cyclic cosmology (2008, background): “It is also known that perturbative string theory breaks down in these and similar settings as soon as interactions are taken into account [71,13,27].”
Local bulk operators in AdS/CFT: A holographic description of the black hole interior (2006, background): “Note that back-reaction/finite N effects play a crucial role in understanding the physics near the singularity, even in the case of BTZ, as discussed in [28, 34, 16] (and references therein).”
The black hole singularity in AdS/CFT (2003, background): “The [M,N ] = [7, 12] Padé has a pole at x = 1.”
A matrix big bang (2005, background): “The conclusion was that 2 → 2 scattering amplitudes across the singularity diverge at tree-level because of large tree-level gravitational backreaction from the region close to the singularity [6].”
Rolling tachyons and decaying branes (2002, unknown): “1 We use units such that � ′ = 1. 2 Other discussions of spatial variation include [4, 9, 10, 11 ].”
Time‐dependent orbifolds and string cosmology (2003, unknown): “For concreteness of exposition, we shall consider only the O–plane orbifold [18], but notice that similar techniques have been used for other orbifolds discussed in these lectures: the amplitudes for the null–boost and null– brane, which can be derived easily from the computation here presented, wer”