Inflationary cosmology- A new approach using Non-linear electrodynamics

Payel Sarkar; Prasanta Kumar Das; Gauranga Charan Samanta

doi:10.1088/1402-4896/abf0d2

paper

Inflationary cosmology- A new approach using Non-linear electrodynamics

arXiv:2005.05568 · doi:10.1088/1402-4896/abf0d2

Abstract

We explore a new kind of field of nonlinear electrodynamics(NLED) which acts as a source of gravity and can accelerate the universe during the inflationary era. We propose a new type of NLED lagrangian which is charecterized by two paremetrs $α$ and $β$ . We investigate the classical stability and causality aspects of this model by demanding that the speed ( $C_{s} = \frac{d P}{d ρ}$ ) of the sound wave $C_{s}^{2} > 0$ and $C_{s} \leq 1$ and find that $0 < C_{s}^{2} < 1$ corresponds to $0.25 \leq α \leq 0.4$ and $0.6 \leq β B^{2} \leq 1$ . A study of the deceleration parameter( $q = \frac{1}{2} (1 + 3 ω)$ , $ω = P / ρ$ being the equation of state parameter) suggests that the value $q < 0$ (i.e. $ω < - 1/3$ and $a ¨ (t) > 0$ ( the accelerating universe)) requires $β B^{2} \geq 0.13$ . During inflation, the energy density $ρ_{B}$ is found to be maximum and is given by $ρ_{B}^{ma x} = 0.65/ β$ corresponding to $α = 0.3$ . The magnetic field necessary to trigger the inflation, is found to be $B (= B_{ma x}) ≃ \frac{0.4 ρ _{B}^{ma x}}{0.65} = 4 \times 1 0^{51} Gauss$ , where $ρ_{B}^{ma x} (= 1 0^{64} GeV^{4}$ ) is the energy density of the universe during inflation. The model also predict the e-fold number $N = 71$ , which agrees with the experimental result.

arXiv comment11 pages, 17 figures

Inflationary cosmology- A new approach using Non-linear electrodynamics

Abstract

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