DBI with Primordial Magnetic Field in the Sky

TL;DR

This paper explores how a specific inflationary model with a speed limit for the inflaton field can generate large-scale primordial magnetic fields of microgauss strength, influenced by reheating details and e-foldings.

Contribution

It introduces a novel inflationary mechanism based on a speed limit that breaks conformal triviality, leading to magnetic field generation during inflation.

Findings

Primordial magnetic field amplitude depends on reheating and e-foldings.

Magnetic fields of order microgauss can be generated during inflation.

The amplitude at decoupling is calculated using late-time behavior.

Abstract

In this paper, we study the generation of a large scale magnetic field with amplitude of order $\mu$G in an inflationary model which has been introduced in hep-th/0310221. This inflationary model based on existence of a speed limit for inflaton field. Generating a mass for inflaton at scale above the $\phi_{IR}$, breaks the conformal triviality of the Maxwell equation and causes to originate a magnetic field during the inflation. The amplitude strongly depends on the details of reheating stage and also depends on the e-foldings parameter N. We find the amplitude of the primordial magnetic field at decoupling time in this inflationary background using late time behavior of the theory.