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arXiv · 1904.12878

Gravitational Waves Induced by Scalar Perturbations during a Gradual Transition from an Early Matter Era to the Radiation Era

Keisuke Inomata·Kazunori Kohri·Tomohiro Nakama·Takahiro Terada
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Abstract

We revisit the effects of an early matter-dominated era on gravitational waves induced by scalar perturbations. We carefully take into account the evolution of the gravitational potential, the source of these induced gravitational waves, during a gradual transition from an early matter-dominated era to the radiation-dominated era, where the transition timescale is comparable to the Hubble time at that time. Realizations of such a gradual transition include the standard perturbative reheating with a constant decay rate. Contrary to previous works, we find that the presence of an early matter-dominated era does not necessarily enhance the induced gravitational waves due to the decay of the gravitational potential around the transition from an early matter-dominated era to the radiation-dominated era.

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Keisuke Inomata, Kazunori Kohri, Tomohiro Nakama, Takahiro Terada. 2019-04-29. Gravitational Waves Induced by Scalar Perturbations during a Gradual Transition from an Early Matter Era to the Radiation Era. https://doi.org/10.1088/1475-7516%2F2019%2F10%2F071

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