@article{32be5bdea8c84a6487c71a4fd9f20030,
title = "Constraining axion inflation with gravitational waves from preheating",
abstract = "We study gravitational wave production from gauge preheating in a variety of inflationary models, detailing its dependence on both the energy scale and the shape of the potential. We show that preheating into Abelian gauge fields generically leads to a large gravitational wave background that contributes significantly to the effective number of relativistic degrees of freedom in the early universe, Neff. We demonstrate that the efficiency of gravitational wave production is correlated with the tensor-to-scalar ratio, r. In particular, we show that efficient gauge preheating in models whose tensor-to-scalar ratio would be detected by next-generation cosmic microwave background experiments (r 10-3) will be either detected through its contribution to Neff or ruled out. Furthermore, we show that bounds on Neff provide the most sensitive probe of the possible axial coupling of the inflaton to gauge fields regardless of the potential.",
author = "Peter Adshead and Giblin, {John T.} and Mauro Pieroni and Weiner, {Zachary J.}",
note = "Funding Information: We thank Mustafa Amin and Jessie Shelton for useful discussions and Valerie Domcke for comments on our draft. Z. J. W. thanks Andreas Kloeckner for generous support and advice on the development of pystella . The work of P. A. was supported in part by NASA Astrophysics Theory Grant No. NNX17AG48G. J. T. G. is supported by the National Science Foundation Grant No. PHY-1719652. M. P. acknowledges the support of the Spanish MINECOs “Centro de Excelencia Severo Ochoa” Programme under Grant No. SEV-2016-059. This project has received funding from the European Unions Horizon 2020 research and innovation programme under the Marie Sk{\l}odowska-Curie Grant Agreement No. 713366. Z. J. W. is supported in part by the United States Department of Energy Computational Science Graduate Fellowship, provided under Grant No. DE-FG02-97ER25308. The development of pystella made use of the Extreme Science and Engineering Discovery Environment (XSEDE) through allocation TG-PHY180049, which is supported by National Science Foundation Grant No. ACI-1548562, and also made use of hardware purchased by the National Science Foundation, Kenyon College, and the Kenyon College Department of Physics. This work made use of the Illinois Campus Cluster, a computing resource that is operated by the Illinois Campus Cluster Program (ICCP) in conjunction with the National Center for Supercomputing Applications (NCSA) and which is supported by funds from the University of Illinois at Urbana-Champaign. P. A. acknowledges the hospitality of the Yukawa Institute for Theoretical Physics at Kyoto University, where some of this work was completed during the YITP-T-19-02 on “Resonant instabilities in cosmology.” Publisher Copyright: {\textcopyright} 2020 American Physical Society.",
year = "2020",
month = apr,
day = "15",
doi = "10.1103/PhysRevD.101.083534",
language = "English (US)",
volume = "101",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "American Physical Society",
number = "8",
}