Late Time Magnetogenesis from Ultralight Scalar Dark Matter
Cosmology and Nongalactic Astrophysics
2026-01-05 v1 General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
Abstract
Assuming that Dark Matter is an ultralight scalar field which is coupled to electromagnetism via a gauge-kinetic function and which at the time of recombination is oscillating coherently over a Hubble patch, we show that there is a tachyonic instability for the gauge field modes which leads to the generation of magnetic fields on cosmological scales of sufficient amplitude to explain observations.
Keywords
Cite
@article{arxiv.2601.00443,
title = {Late Time Magnetogenesis from Ultralight Scalar Dark Matter},
author = {V. Kamali and R. Brandenberger},
journal= {arXiv preprint arXiv:2601.00443},
year = {2026}
}
Comments
5 pages, no figures