Primordial magnetic fields from gravitationally coupled electrodynamics in nonsingular bounce cosmology

• 来源期刊: 中国科学（物理学 力学 天文学）
• 年，卷（期）: 2018,（10）
• 页码范围: 43-50
• 页数: 8页
• 语种: 中文

摘要

We in this paper study a class of mechanism of the production of the primordial magnetic field (PMF) in the non-singular bouncing cosmology,through the coupling of the electromagnetic field to gravity.We adopt an electrodynamic model with a coupling coefficient as a function of the scale factor a,i.e.,f =1 + (a/a*)-n,with a* and n ＞ 0 being constants.With analytical calculations,we find that this model can yield a blue tilted power spectrum of PMF on large scales from 1 Mpc to the Hubble length if the bounce scenario has experienced a contracting phase with an equation-of-state parameter larger than-1/3.Furthermore,in order to satisfy the constraints of observational data,the present mechanism favors the so-called ekpyrotic-bounce paradigm.The back-reaction of the energy density of PMF at the bouncing point can lead to additional theoretical constraints on the underlying bouncing paradigm.