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arXiv · hep-th/0503148

D-branes in a Big Bang/Big Crunch Universe: Nappi-Witten Gauged WZW Model

Yasuaki Hikida·Rashmi R. Nayak·Kamal L. Panigrahi
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Abstract

We study D-branes in the Nappi-Witten model, which is a gauged WZW model based on (SL(2,R) x SU(2)) / (U(1) x U(1)). The model describes a four dimensional space-time consisting of cosmological regions with big bang/big crunch singularities and static regions with closed time-like curves. The aim of this paper is to investigate by D-brane probes whether there are pathologies associated with the cosmological singularities and the closed time-like curves. We first classify D-branes in a group theoretical way, and then examine DBI actions for effective theories on the D-branes. In particular, we show that D-brane metric from the DBI action does not include singularities, and wave functions on the D-branes are well behaved even in the presence of closed time-like curves.

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Yasuaki Hikida, Rashmi R. Nayak, Kamal L. Panigrahi. 2005-05-06. D-branes in a Big Bang/Big Crunch Universe: Nappi-Witten Gauged WZW Model. https://doi.org/10.1088/1126-6708%2F2005%2F05%2F018

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