Pre-reheating magnetogenesis in the kinetic coupling model

Tomohiro Fujita, Ryo Namba

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


Recent blazar observations provide growing evidence for the presence of magnetic fields in the extragalactic regions. While natural speculation is to associate the production with inflationary physics, it is known that magnetogenesis solely from inflation is quite challenging. We therefore study a model in which a noninflaton field χ coupled to the electromagnetic field through its kinetic term, -I2(χ)F2/4, continues to move after inflation until the completion of reheating. This leads to a postinflationary amplification of the electromagnetic field. We compute all the relevant contributions to the curvature perturbation, including gravitational interactions, and impose the constraints from the CMB scalar fluctuations on the strength of magnetic fields. We, for the first time, explicitly verify both the backreaction and CMB constraints in a simple yet successful magnetogenesis scenario without invoking a dedicated low-scale inflationary model in the weak-coupling regime of the kinetic coupling model.

Original languageEnglish
Article number043523
JournalPhysical Review D
Issue number4
Publication statusPublished - 2016 Aug 22
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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