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AT1 - Extended Theories of Gravity and Quantum Cosmology

Speaker

Sakakihara, Yuki

Coauthors

Jiro Soda

Talk Title

Inflationary spacetime and primordial gravitational waves in bimetric gravity

Abstract

We examined inflationary spacetime and the gravitational waves generated during inflation in bimetric gravity. We first analyzed the stability of de Sitter spacetime which is the slow-roll limit of inflationary spacetime and obtained stable solutions. Next, we studied inflationary solutions which correspond to the obtained stable de Sitter solutions by introducing a inflaton coupling with the physical metric. We calculated tensor perturbations on the inflationary background and we clarified the expressions of the tensor amplitude and the spectral index. Since the physical metric is represented as the superposition of the massive graviton and the massless graviton, the amplitude is suppressed compared to that in GR cases and the spectral index depends on the ratio of the spatial scales of the physical metric and the other metric.

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