# Magnetogenesis from a rotating scalar: \`a la scalar chiral magnetic effect

## TL;DR

This paper explores how a rotating pseudo-scalar field can induce electromagnetic currents analogous to the chiral magnetic effect, leading to potential cosmological implications such as magnetic field generation.

## Contribution

It introduces a novel mechanism linking pseudo-scalar field dynamics to magnetic field generation via an anomalous coupling, inspired by the Affleck-Dine scenario.

## Key findings

- Pseudo-scalar field dynamics can induce electromagnetic currents similar to the CME.
- Initial phase velocity and anomalous coupling lead to magnetic field instabilities.
- Cosmological magnetic field generation is possible through this mechanism.

## Abstract

The chiral magnetic effect (CME) is a phenomenon in which an electric current is induced parallel to an external magnetic field in the presence of chiral asymmetry in a fermionic system. In this paper, we show that the electric current induced by the dynamics of a pseudo-scalar field which anomalously couples to electromagnetic fields can be interpreted as closely analogous to the CME. In particular, the velocity of the pseudo-scalar field, which is the phase of a complex scalar, indicates that the system carries a global U(1) number asymmetry as the source of the induced current. We demonstrate that an initial kick to the phase-field velocity and an anomalous coupling between the phase-field and gauge fields are naturally provided, in a set-up such as the Affleck-Dine mechanism. The resulting asymmetry carried by the Affleck-Dine field can give rise to instability in the (electro)magnetic field. Cosmological consequences of this mechanism are also investigated.