Sign-flipping axion potentials via Kapitza-type modulation by heavy axions
Abstract
A bstract We show that the potential of a light axion can flip sign, or even nearly vanish, as a result of coherent oscillations of a heavier axion with which it mixes. This phenomenon is analogous to the Kapitza pendulum, where a high-frequency external force stabilizes an otherwise unstable configuration, but here it arises naturally from the inherent mass hierarchy and mixing among axions in the axiverse, without the need for any externally imposed modulation. We further show that a late-time sign flip of the potential can significantly enhance the abundance of the light axion, which has important cosmological and observational consequences. Such dynamics may also be realized in multi-natural inflation, or inside oscillons and boson stars formed by a heavy axion.
Fields of Study & Subjects
Dark Matter and Cosmic Phenomena
Quantum Mechanics and Applications
Cosmology and Gravitation Theories
Publication details
- Journal / source
- Journal of High Energy Physics
- Publisher
- Springer Science and Business Media LLC
- Volume
- 2026
- Issue
- 7
- Publication date
- 17 July 2026
- Language
- EN