https://doi.org/10.1140/epjc/s10052-023-11963-4
Regular Article - Theoretical Physics
Pulsar timing array observations as possible hints for nonsingular cosmology
1
School of Physics and Microelectronics, Zhengzhou University, 450001, Zhengzhou, Henan, China
2
Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-348, Kraków, Poland
3
Institute Lorentz, Leiden University, PO Box 9506, 2300 RA, Leiden, The Netherlands
b
ye@lorentz.leidenuniv.nl
c yongcai_phy@outlook.com, caiyong@zzu.edu.cn
Received:
8
August
2023
Accepted:
25
August
2023
Published online:
13
September
2023
Recent pulsar timing array (PTA) experiments have reported strong evidence of the stochastic gravitational wave background (SGWB). If interpreted as primordial gravitational waves (GWs), the signal favors a strongly blue-tilted spectrum. Consequently, the nonsingular cosmology, which is able to predict a strongly blue-tilted GW spectrum with 
on certain scales, offers a potential explanation for the observed SGWB signal. In this paper, we present a Genesis-inflation model capable of explaining the SGWB signal observed by the PTA collaborations while also overcoming the initial singularity problem associated with the inflationary cosmology. Furthermore, our model predicts distinctive features in the SGWB spectrum, which might be examined by forthcoming space-based gravitational wave experiments.
© The Author(s) 2023
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