Related papers: Primordial large-scale electromagnetic fields from…
We briefly discuss cosmic inflation, which is the dominant paradigm for the generation of the large scale structure in the Universe and also for arranging for the initial conditions of the hot Big Bang. We then present quintessential…
With an energy scale that can be as high as $10^{14}\,{\rm GeV}$, inflation may provide a unique probe of high-energy physics. Both scalar and tensor fluctuations generated during this early accelerated expansion contain crucial information…
A new model of nonlinear electrodynamics with dimensional parameters $\beta$ and $\gamma$ is proposed. The principles of causality and unitarity are studied. We show that a singularity of the electric field at the origin of charges is…
The primordial spectrum of fluctuations may present a large peak as a result of enhancing features during inflation. This may include, but is not limited to, bumps in the inflaton's potential, phases of ultra-slow-roll or turns in…
The origin of galactic and extra-galactic magnetic fields is an unsolved problem in modern cosmology. A possible scenario comes from the idea of these fields emerged from a small field, a seed, which was produced in the early universe…
We use the $f^{2}FF$ model to study the generation of primordial magnetic fields (PMF) in the context of large field inflation (LFI), described by the potential, $V \sim M \phi^{p}$. We compute the magnetic and electric spectra for all…
Generation of primordial magnetic fields during inflation typically requires the breaking of conformal invariance of the Electromagnetic action. In this paper this has been achieved naturally in a higher dimensional cosmological model with…
The deep interrelation between elementary particle physics and cosmology manifests itself when one considers the contribution of quantum fluctuations of vacuum fields to the dark energy and the effective cosmological constant. The…
Primordial inflation is regarded to be driven by a phantom field which is here implemented as a scalar field satisfying an equation of state $p=\omega\rho$, with $\omega<-1$. Being even aggravated by the weird properties of phantom energy,…
There has been a growing evidence for the existence of magnetic fields in the extra-galactic regions, while the attempt to associate their origin with the inflationary epoch alone has been found extremely challenging. We therefore take into…
We investigate the generation of primordial magnetic fields from stochastic currents created by the cosmological transition from inflation to reheating. We consider N charged scalar fields coupled to the electromagnetic field in a curved…
Cosmologists have embraced a particular ad hoc formula for the primordial power spectrum from inflation for universes with $\Omega_0 < 1$. However, the so-called ``Open Inflation'' models, which are attracting renewed interest in the…
We explore the generation of large-scale magnetic fields in the so-called moduli inflation. The hypercharge electromagnetic fields couple to not only a scalar field but also a pseudoscalar one, so that the conformal invariance of the…
Inflation has long been the accepted paradigm for understanding the early universe. Most models of inflation have a scalar field acting as the inflaton particle which decays after inflation during a process called reheating into standard…
Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable in any realistic terrestrial experiment. Theoretical insights into the inflationary era and its observational probes may…
(abridged) We suggest here that the large scale fields $\sim \mu$G, observed in galaxies at both high and low redshifts by Faraday Rotation Measurements (FRMs), have their origin in the electromagnetic fluctuations that naturally occurred…
The detection of a primordial stochastic gravitational wave background has the potential to reveal unprecedented insights into the early universe, and possibly into the dynamics of inflation. Generically, UV-complete inflationary models…
The effective field theory (EFT) of inflation provides a natural framework to study the new physical effects on primordial perturbations. Recently a healthy extension of the EFT of inflation with high-order operators has been proposed,…
We investigate if the observed small and nearly scale-invariant primordial cosmic perturbation, i.e. the perturbation amplitude $P_\zeta\sim10^{-9}$ and the spectral index $n_s \simeq 0.965$, is typical in the landscape of vacua after…
Blazar observations point toward the possible presence of magnetic fields over intergalactic scales of the order of up to $\sim1\,$Mpc, with strengths of at least $\sim10^{-16}\,$G. Understanding the origin of these large-scale magnetic…