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arXiv · 1404.3102

Beginning of Universe through large field hybrid inflation

Tatsuo Kobayashi·Osamu Seto
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Abstract

Recent detection of $B$-mode polarization induced from tensor perturbations by the BICEP2 experiment implies so-called large field inflation, where an inflaton field takes super-Planckian expectation value during inflation, at a high energy scale. We show however, if another inflation follows hybrid inflation, the hybrid inflation can generate a large tensor perturbation with not super-Plankian but Planckian field value. This scenario would relax the tension between BICEP2 and Planck concerning the tensor-to-scalar ratio, because a negative large running can also be obtained for a certain number of e-fold of the hybrid inflation. A natural interpretation of a large gravitational wave mode with or without the scalar spectral running might be multiple inflation in the early Universe.

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Tatsuo Kobayashi, Osamu Seto. 2015-06-30. Beginning of Universe through large field hybrid inflation. https://doi.org/10.1142/s0217732315501060

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