Cosmological magnetic fields

Abstract

Magnetic fields are observed not only in stars, but in galaxies, clusters, and even high redshift Lyman-α systems. In principle, these fields could play an important role in structure formation and also affect the anisotropies in the cosmic microwave background radiation (CMB). The study of cosmological magnetic fields aims not only to quantify these effects on large-scale structure and the CMB, but also to answer one of the outstanding puzzles of modern cosmology: when and how do magnetic fields originate? They are either primordial, i.e. created before the onset of structure formation, or they are generated during the process of structure formation itself.

Effective potential at finite temperature in a constant hypermagnetic field: Ring diagrams in the standard model

“…We use instead the requirement that the magnetic energy density ρ mag ∼ B 2 should be smaller than the overall radiation energy density ρ rad ∼ T 4 at nucleosynthesis, in order to preserve the estimated abundances of light elements. With this, one obtains the simple bound B < ∼ T 2 [24]. On the other hand stability conditions against the formation of W -condensate indicate [25] that the field strength is also weak compared to the square of the W mass, m 2 W .…”

Imperfect Barotropic Magnetic Tilted Cosmological Model

“…This leads to F 12 = 0 = F 13 by virtue of (7). We also find that F 14 = 0 = F 24 due to the assumption of infinite conductivity (Maartens [24])of the fluid. We take the incident magnetic field to be in the direction of x-axis so that the only non-vanishing component of F ij is F 23 .…”

Symmetry restoration at finite temperature with weak magnetic fields

“…With this, one obtains the simple bound B T 2 [36]. Furthermore, to guarantee stability conditions against the formation of a W -condensate [37], one obtains that the field is also weak compared to m 2 W .…”