Regular Article - Theoretical Physics
Observer-dependent D-brane for strings propagating in pp-wave time-dependent background
Universidade Federal do Pampa – UNIPAMPA, Rua Carlos Barbosa s/n, Bairro Getúlio Vargas, CEP 96412-420, Bagé, RS, Brazil
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Published online: 27 March 2008
We study the type IIB superstring in a pp-wave time-dependent background, which has a singularity at t=0. We show that this background can provide a toy model to study some ideas related to the stretched horizon paradigm and the complementary principle of black holes. To this end, we construct a unitary Bogoliubov generator that relates the asymptotically flat string Hilbert space, defined at t=±∞, to the finite time Hilbert space. For asymptotically flat observers, the closed string vacuum close to the singularity appears as a boundary state, which is in fact a D-brane described in the closed string channel. However, observers who go with the string towards the singularity see the original vacuum.
© Springer-Verlag , 2008