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Constraining axion inflation with gravitational waves across 29 decades in frequency

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arxiv 1909.12843 v2 pith:KRSGHCAU submitted 2019-09-27 astro-ph.CO hep-ph

Constraining axion inflation with gravitational waves across 29 decades in frequency

classification astro-ph.CO hep-ph
keywords gaugegravitationalpreheatingconstraintswavesaxioncouplingdemonstrate
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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We demonstrate that gravitational waves generated by efficient gauge preheating after axion inflation generically contribute significantly to the effective number of relativistic degrees of freedom $N_\mathrm{eff}$. We show that, with existing Planck limits, gravitational waves from preheating already place the strongest constraints on the inflaton's possible axial coupling to Abelian gauge fields. We demonstrate that gauge preheating can completely reheat the Universe regardless of the inflationary potential. Further, we quantify the variation of the efficiency of gravitational wave production from model to model and show that it is correlated with the tensor-to-scalar ratio. In particular, when combined with constraints on models whose tensor-to-scalar ratios would be detected by next-generation cosmic microwave background experiments, $r\gtrsim 10^{-3}$, constraints from $N_\mathrm{eff}$ will probe or rule out the entire coupling regime for which gauge preheating is efficient.

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Cited by 12 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

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    astro-ph.CO 2025-08 conditional novelty 7.0

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    astro-ph.CO 2026-07 conditional novelty 6.0

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