相关论文: Gradient expansion formalism for magnetogenesis in…
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,…
While during inflation a phase of increasing gauge coupling allows for a scale-invariant hyperelectric spectrum, when the coupling decreases a flat hypermagnetic spectrum can be generated for typical wavelengths larger than the effective…
The interplay among the possible variation of gauge coupling and the inflationary dynamics is investigated in a simplified toy model. Depending upon various parameters (scalar mass, curvature scale at the end of inflation and at the onset…
In this work, we study general features of a regime where gauge fields produced during inflation cause a strong backreaction on the background evolution and its impact on the spectrum and the correlation length of gauge fields. With this…
We study the generation of magnetic fields during inflation making use of a coupling of the inflaton and moduli fields to electromagnetism via the photon kinetic term, and assuming that the coupling is an increasing function of time. We…
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…
In this paper, we discuss the inflationary magnetogenesis scenario, in which the coupling function is introduced to break the conformal invariance of electromagnetic action. Unlike in conventional models, we deduce the Maxwell's equations…
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 consider the possibility of inflationary magnetogenesis due to dynamical couplings of the electromagnetic fields to gravity. We find that large primordial magnetic fields can be generated during inflation without the strong coupling…
The simplest model of primordial magnetogenesis can provide scale-invariant magnetic fields that can explain the present abundances of it in the cosmic scales. Two kinds of solutions of the coupling function can lead to such phenomena and…
We describe a simple scenario of inflationary magnetogenesis based on a helical coupling to electromagnetism. It allows to generate helical magnetic fields of strength of order up to $10^{- 7}\,\text{G}$, when extrapolated to the current…
By assuming the kinetic coupling $f^{2}(\phi)FF$ of the effective inflaton field $\phi$ with the electromagnetic field, we explore magnetogenesis during the inflation and preheating stages in the Starobinsky model. We consider the case of…
We study the amplification of large-scale magnetic fields during preheating and inflation in several different models. Preheating can resonantly amplify seed fields on cosmological scales. In the presence of conductivity, however, the…
The effective approach is applied to the analysis of inflationary magnetogenesis. Rather than assuming a particular underlying description, all the generally covariant terms potentially appearing with four space-time derivatives in the…
Cosmological magnetic fields pervade the entire universe, from small to large scales. Since they apparently extend into the intergalactic medium, it is tantalizing to believe that they have a primordial origin, possibly being produced…
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…
The simplest gauge invariant models of inflationary magnetogenesis are known to suffer from the problems of either large backreaction or strong coupling, which make it difficult to self-consistently achieve cosmic magnetic fields from…
Models of inflationary magnetogenesis with a coupling to the electromagnetic action of the form $f^2 F_{\mu\nu}F^{\mu\nu}$, are known to suffer from several problems. These include the strong coupling problem, the back reaction problem and…
A viable class of magnetogenesis models can be constructed by coupling the kinetic term of the hypercharge to a spectator field whose dynamics does not affect the inflationary evolution. The magnetic power spectrum is explicitly related to…
We consider helical coupling to electromagnetism and present a simple scenario of evolution of the coupling function leading to a viable inflationary magnetogenesis without the problem of back-reaction. In this scenario, helical magnetic…