Parker Bound and Monopole Pair Production from Primordial Magnetic Fields

TL;DR

This paper derives new, stronger bounds on the cosmic abundance of magnetic monopoles by analyzing the survival of primordial magnetic fields and their interaction with monopoles, surpassing previous bounds from galactic fields and direct searches.

Contribution

It introduces novel bounds on monopole abundance based on primordial magnetic field survival, considering monopole production via the Schwinger effect.

Findings

New bounds are stronger than Parker bounds and direct search limits.

Primordial magnetic fields can produce monopoles through the Schwinger effect.

Conditions for the survival of primordial magnetic fields are established.

Abstract

We present new bounds on the cosmic abundance of magnetic monopoles based on the survival of primordial magnetic fields during the reheating and radiation-dominated epochs. The new bounds can be stronger than the conventional Parker bound from galactic magnetic fields, as well as bounds from direct searches. We also apply our bounds to monopoles produced by the primordial magnetic fields themselves through the Schwinger effect, and derive additional conditions for the survival of the primordial fields.