Related papers: Magnetogenesis in Cyclical Universe
Despite their ubiquity, there are many open questions regarding galactic and cosmic magnetic fields. Specifically, current observational constraints cannot rule out if magnetic fields observed in galaxies were generated in the Early…
We present a simplified model in which we suggest that two important galactic problems -the magnetic field configuration at large scales and the flat rotation curve- may be simultaneously explained. A highly convective disc produces a high…
We show that the decaying magnetohydrodynamic turbulence leads to a more rapid growth of the correlation length of a primordial magnetic field than that caused by the expansion of the Universe. As an example, we consider the magnetic fields…
After a brief review of different types of scenarios suggested for the solution of the problem of galactic and intergalactic magnetic field generation, the mechanism based on the electric current induction by hypothetical millicharged…
The $R^2$ term in the Starobinsky inflationary model can be regarded as a leading quantum correction to the gravitational effective action. We assume that parity-preserving and parity-violating (axial) non-minimal couplings between…
Magnetic fields of debated origin appear to permeate the Universe on all large scales. There is mounting evidence that supernovae produce not only roughly spherical ejecta and winds, but also highly relativistic jets of ordinary matter.…
The origin of extragalactic magnetic fields is still poorly understood. Based on a dedicated suite of cosmological magneto-hydrodynamical simulations with the ENZO code we have performed a survey of different models that may have caused…
It is possible that the expansion of the universe began with an inflationary phase, in which the inflaton driving the process also was a Higgs field capable of stabilizing magnetic monopoles in a grand-unified gauge theory. If so, then the…
In scalar-tensor Horndeski theories, nonsingular cosmological models - bounce and genesis - are problematic because of potential ghost and/or gradient instabilities. One way to get around this obstacle is to send the effective Planck mass…
Using the simplest model for a bouncing universe, namely that for which gravity is described by pure general relativity, the spatial sections are positively curved and the matter content is a single scalar field, we obtain the transition…
The generation of a magnetic field in the Early Universe is considered, due to the gravitational production of the Z-boson field during inflation. Scaled to the epoch of galaxy formation this magnetic field suffices to trigger the galactic…
Magnetic monopoles are a long-standing prediction of Grand Unified Theories, yet their efficient production in early universe phase transitions would lead to a monopole abundance that far exceeds observational limits. The standard solution…
The primordial density fluctuation inevitably couples to all forms of matter via loop corrections and depends on the ambient conditions while inflation was ongoing. This gives us an opportunity to observe processes which were in progress…
We propose a novel scenario to generate primordial magnetic fields during inflation induced by an oscillating coupling of the electromagnetic field to the inflaton. This resonant mechanism has two key advantages over previous proposals.…
The origin of the magnetic field in galaxies is an open question in astrophysics. Several mechanisms have been proposed related, in general, with the generation of small seed fields amplified by a dynamo mechanism. In general, these…
Observations of $\gamma$-ray from blazars suggest the presence of magnetic fields in the intergalactic medium, which may require a primordial origin. Intense enough primordial magnetic fields can arise from theories of dynamical electroweak…
Cosmological models involving a bounce from a contracting to an expanding universe can address the standard cosmological puzzles and generate "primordial" density perturbations without the need for inflation. Some such models, in particular…
We calculate, in the free Maxwell theory, the renormalized quantum vacuum expectation value of the two-point magnetic correlation function in de Sitter inflation. We find that quantum magnetic fluctuations remain constant during inflation…
At astrophysical and cosmological scales, there is a detectable amount of magnetic field. There are several probable origins for this observed magnetic field, including the possibility of its origin in the early Universe. There are several…
We use the phase plane analysis technique of Madsen and Ellis to consider a universe with a true cosmological constant as well as a cosmological "constant" that is decaying. Time symmetric dynamics for the inflationary era allows eternally…