DBI with primordial magnetic field in the sky

Abstract

In this paper, we study the generation of a large scale magnetic field with amplitude of order µG 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 φ 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.

Higher order statistics of curvature perturbations inIFFmodel and its Planck constraints

“…We consider the kinetic coupling model [1][2][3][4][5][6][7][8] in this paper. Although it can not generate the primordial magnetic field which is strong enough to be more than 10 −15 G at present [15][16][17], it is nicely simple and gives us the essential understanding of the problem.…”

“…Although a U(1) gauge field is not fluctuated during inflation in its minimal form due to the conformal symmetry, several ideas to extend it are proposed. Among them, the kinetic coupling model [1] is nicely simple, free of ghost instabilities [2] and well motivated by the supergravity or the string theory frame work [3][4][5][6][7][8]. The model action is given by…”

Generic estimates for magnetic fields generated during inflation including Dirac-Born-Infeld theories

“…In this case one has I(φ) = 1, which means that the generation of the magnetic field does not occur unlike the results found in Ref. [38]. Since the coupling f 3 (φ) given above is chosen to reproduce the standard Maxwell Lagrangian in the low-energy regime (f φ2 ≪ 1), the field φ is not directly coupled to the electromagnetic field.…”

Inflation from charged scalar and primordial magnetic fields?

“…one requires that b 1 = 1 and b 2 = 0 in Eq. (21). On the other hand, for long wavelength modes, k|τ | → 0, and by using the asymptotic relation…”