Related papers: Magnetogenesis in Matter - Ekpyrotic Bouncing Cosm…
The large-scale magnetic fields we observe today in galaxies and galaxy clusters could be the result of a pure quantum effect taking place during inflation, to wit, the creation of particles (photons) out from the vacuum in a curved…
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…
Recent observational claims of magnetic fields stronger than $10^{-16}$ G in the extragalactic medium motivate a new look for their origin in the inflationary magnetogenesis models. In this work we shall review the constraints on the…
In previous work, two of us have proposed a model of inflationary magnetogenesis based on a rolling auxiliary field able both to account for the magnetic fields inferred by the (non) observation of gamma-rays from blazars, and to start the…
Recent blazar observations provide growing evidence for the presence of magnetic fields in the extragalactic regions. While a natural speculation is to associate the production to inflationary physics, it has been known that magnetogenesis…
A bouncing cosmology with an initial matter-dominated phase of contraction during which scales which are currently probed with cosmological observations exit the Hubble radius provides a mechanism alternative to inflation for producing a…
A primordial magnetic field may be generated during an inflationary period if conformal invariance is broken. We reexamine and generalize previous results about the magnetic field produced by couplings of the form $R^n…
Bouncing scenarios offer an alternative to the inflationary paradigm for the generation of perturbations in the early universe. Recently, there has been a surge in interest in examining the issue of primordial magnetogenesis in the context…
The origin of large scale cosmological magnetic fields remains a mystery, despite the continuous efforts devoted to that problem. We present a new model of magnetic field generation, based on local charge separation provided by an…
The evolution of the gauge coupling is modelled using a scalar degree of freedom whose homogeneous and inhomogeneous modes evolve from an ordinary inflationary phase to the subsequent epochs. Depending upon various parameters (scalar mass,…
If cosmic magnetic fields are indeed produced during inflation, they are likely to be correlated with the scalar metric perturbations that are responsible for the Cosmic Microwave Background anisotropies and Large Scale Structure. Within an…
We propose a novel mechanism to generate primordial magnetic fields (PMFs) strong enough to explain the observed cosmic magnetic fields. We employ a scalar field charged under U(1) gauge symmetry with a non-trivial VEV to provide an…
In this paper, we discussed the multiple vector fields during the inflation era and the inflationary magnetogenesis with multiple vector fields. Instead of a single coupling function in single vector field models, the coupling matrix…
We propose a novel mechanism for significantly enhancing the amplitude of primordial electromagnetic fields during inflation. Similar to existing proposals, our idea is based on parametric resonance effects due to…
We study the generation of large scale primordial magnetic fields by a cosmological phase transition during the radiation dominated era. The setting is a theory of N charged scalar fields coupled to an abelian gauge field, that undergoes a…
Bouncing models of cosmology, as they arise e.g. in loop quantum cosmology, can be followed by an inflationary phase and generate close-to-scale-invariant fluctuation spectra as observed in the Cosmic Microwave Background (CMB). However,…
A nonsingular emergent universe cosmology can be realized by a nonconventional spinor field as first developed in \cite{Cai:2012yf}. We study the mechanisms of generating scale-invariant primordial power spectrum of curvature perturbation…
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…
It has been recently proposed that the presence of a temporal electromagnetic field on cosmological scales could explain the phase of accelerated expansion that the universe is currently undergoing. The field contributes as a cosmological…
We point out that a successful inflationary magnetogenesis could be realised if we break the local U(1) gauge symmetry during inflation. The effective electric charge is fixed as a fundamental constant, which allows us to obtain an almost…