The equivalence between Einstein and Jordan frames: a study based on the inflationary magnetogenesis model
Year: 2025
Type: article
Abstract: The equivalence of the Jordan and Einstein frames has been a subject of considerable interest in the field. In this paper, within the context of [Formula: see text] gravity, we explore the inflationary magnetogenesis model, focusing on the magnetic field energy density and its spectrum in both the Jordan and Einstein frames to elucidate the equivalence between these two reference frames. Our analysis reveals that during the inflationary epoch, while the magnetic field exhibits a scale-invariant spectrum in the Einstein frame, it demonstrates a blue spectrum in the Jordan frame. And we compared our findings with the results derived from the analysis of observational data by other researchers and found them to be consistent. Additionally, we investigate the post-inflationary evolution of the magnetic field’s energy density in both frames, uncovering that for scale-invariant spectra in the Einstein frame during inflation, the magnetic field transitions to a blue spectrum, whereas in the Jordan frame, it evolves into a red spectrum. We also establish the conditions under which both frames may exhibit scale-invariant spectra simultaneously during the inflationary period. Finally, we discuss the validity of our conclusions for other [Formula: see text] gravity theories.
Authors: Hang Wang, Shuang Liu, Yu Li, Yao-Chuan Wang
Institution: Dalian Maritime University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2041883780, G2395616354
OpenAlex ID: W4416158404