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arXiv · 1710.00305

Cosmological imprints of string axions in plateau

Jiro Soda·Yuko Urakawa
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Abstract

We initiate a study on various cosmological imprints of string axions whose scalar potentials have plateau regions. In such cases, we show that a delayed onset of oscillation generically leads to a parametric resonance instability. In particular, for ultralight axions, the parametric resonance can enhance the power spectrum slightly below the Jeans scale, alleviating the tension with the Lyman $α$ forest observations. We also argue that a long-lasting resonance can lead to an emission of gravitational waves at the frequency bands which are detectable by gravitational wave interferometers and pulsar timing arrays.

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Jiro Soda, Yuko Urakawa. 2018-12-14. Cosmological imprints of string axions in plateau. https://doi.org/10.1140/epjc%2Fs10052-018-6246-6

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