Regular Article – Theoretical Physics
Resonance instability of primordial gravitational waves during inflation in Chern–Simons gravity
Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, 410081, Changsha, Hunan, China
2 School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 310024, Hangzhou, China
3 School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
4 Institute for Theoretical Physics and Cosmology, Zhejiang University of Technology, 310032, Hangzhou, Zhejiang, China
5 United Center for Gravitational Wave Physics (UCGWP), Zhejiang University of Technology, 310032, Hangzhou, Zhejiang, China
Accepted: 23 February 2021
Published online: 1 March 2021
We investigate axion inflation where the gravitational Chern–Simons term is coupled to a periodic function of the inflaton. We find that tensor perturbations with different polarizations are amplified in different ways by the Chern–Simons coupling. Depending on the model parameters, the resonance amplification results in a parity-violating peak or a board plateau in the energy spectrum of gravitational waves, and the sharp cutoff in the infrared region constitutes a characteristic distinguishable from stochastic gravitational wave backgrounds produced by matter fields in Einstein gravity.
© The Author(s) 2021
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3