|Speaker:||Rajeev Kumar Jain (U Southern Denmark)|
|Title:||Cosmological magnetic fields from inflation and their non-Gaussian imprints|
|Date (JST):||Fri, Nov 07, 2014, 15:30 - 16:30|
|Place:||Seminar Room C|
Primordial magnetic fields are generated during inflation if the conformal invariance of the electromagnetic action is broken. For the case of kinetic coupling model which is one of the simplest gauge invariant models of inflationary magnetogenesis, I will discuss the constraints arising from the strong coupling, backreaction and the anisotropies due to the induced bispectrum of the generated electromagnetic fields. We find that in the best case scenario, the maximal allowed magnetic field strength from inflation on the Mpc scale is less than 10^(-30)G.
In the later part of my talk, I will discuss non-Gaussian imprints of cosmic magnetic fields by means of a cross-correlation between the primordial curvature perturbations and magnetic fields. Such a correlation serves as a new contribution to the non-Gaussian signatures induced by primordial magnetic fields. We show that there exists a simple consistency relation for this cross-correlation in the squeezed limit while the signal is maximized for the flattened configuration where the magnetic non-linear parameter becomes as large as O(10^3). Detectability of such a correlation can both provide a new observational window to the underlying theory of cosmic inflation, and also shed light on the origin of cosmic magnetic fields.