https://doi.org/10.1140/epjc/s10052-024-13340-1
Regular Article - Theoretical Physics
Climbing over the potential barrier during inflation via null energy condition violation
1
School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, UCAS, 310024, Hangzhou, China
2
Institute for Astrophysics, School of Physics, Zhengzhou University, 450001, Zhengzhou, Henan, China
3
School of Physics, University of Chinese Academy of Sciences, 100049, Beijing, China
4
International Center for Theoretical Physics Asia-Pacific, Beijing, Hangzhou, China
5
Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, 100190, Beijing, China
6
University of Chinese Academy of Sciences, 100190, Beijing, China
a
panshi22@mails.ucas.ac.cn
b
caiyong@zzu.edu.cn
c
yspiao@ucas.ac.cn
Received:
7
July
2024
Accepted:
4
September
2024
Published online:
27
September
2024
The violation of the null energy condition (NEC) may play a crucial role in enabling a scalar field to climb over high potential barriers, potentially significant in the very early universe. We propose a single-field model where the universe sequentially undergoes a first stage of slow-roll inflation, NEC violation, and a second stage of slow-roll inflation. Through the NEC violation, the scalar field climbs over high potential barriers, leaving unique characteristics on the primordial gravitational wave power spectrum, including a blue-tilted nature in the middle-frequency range and diminishing oscillation amplitudes at higher frequencies. Additionally, the power spectrum exhibits nearly scale-invariant behavior on both large and small scales.
© The Author(s) 2024
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