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Primordial gravitational waves in inflationary braneworld

Tsutomu Kobayashi·Hideaki Kudoh·Takahiro Tanaka
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Abstract

We study primordial gravitational waves from inflation in Randall-Sundrum braneworld model. The effect of small change of the Hubble parameter during inflation is investigated using a toy model given by connecting two de Sitter branes. We analyze the power spectrum of final zero-mode gravitons, which is generated from the vacuum fluctuations of both initial Kaluza-Klein modes and zero-mode. The amplitude of fluctuations is confirmed to agree with the four-dimensional one at low energies, whereas it is enhanced due to the normalization factor of zero-mode at high energies. We show that the five-dimensional spectrum can be well approximated by applying a simple mapping to the four-dimensional fluctuation amplitude.

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Tsutomu Kobayashi, Hideaki Kudoh, Takahiro Tanaka. 2003-11-21. Primordial gravitational waves in inflationary braneworld. https://doi.org/10.1103/physrevd.68.044025

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