Using Gravitational Waves to put limits on Primordial Magnetic Fields

TL;DR

This paper introduces a method using simulated gravitational wave perturbations to constrain the strength of primordial magnetic fields, with initial application to the era of nucleosynthesis.

Contribution

The paper presents a novel technique for constraining early universe magnetic fields using gravitational wave simulations, extending analysis to various epochs.

Findings

Upper limits on primordial magnetic field strength at nucleosynthesis

Magnetic seed fields were still amplifying before nucleosynthesis

Technique applicable to multiple cosmological epochs

Abstract

We describe a technique for using simulated tensor perturbations in order to place upper limits on the intensity of magnetic fields in the early universe. As an example, we apply this technique to the beginning of primordial nucleosynthesis. We determined that any magnetic seed fields that existed before that time were still in the process of being amplified. In the future, we plan to apply this technique to a wider range of initial magnetic fields and cosmological epochs.