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We present a five dimensional unified theory of gravity and electromagnetism which leads to modified Maxwell equations, suggesting a new origin for galactic magnetic fields. It is shown that a region with nonzero scalar curvature would…

General Relativity and Quantum Cosmology · Physics 2009-11-19 A. Borzou , H. R. Sepangi , R. Yousefi , A. H. Ziaie

The generation of large-scale magnetic fields is studied in inflationary cosmology. We consider the violation of the conformal invariance of the Maxwell field by dilatonic as well as non-minimal gravitational couplings. We derive a general…

Astrophysics · Physics 2009-11-11 Kazuharu Bamba , Misao Sasaki

Detailed physical processes of magnetic field generation from density fluctuations in the pre-recombination era are studied. Solving Maxwell equations and the generalized Ohm's law, the evolutions of the net charge density, the electric…

Astrophysics · Physics 2008-11-26 Keitaro Takahashi , Kiyotomo Ichiki , Naoshi Sugiyama

We show that the presence of a temporal electromagnetic field on cosmological scales generates an effective cosmological constant which can account for the accelerated expansion of the universe. Primordial electromagnetic quantum…

Astrophysics · Physics 2011-07-13 Jose Beltran Jimenez , Antonio L. Maroto

We investigate the generation of features at large scales in the primordial power spectrum (PPS) when inflation is driven by two scalar fields. In canonical single field models of inflation, these features are often generated due to…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-19 Matteo Braglia , Dhiraj Kumar Hazra , L. Sriramkumar , Fabio Finelli

We discuss the generation of large-scale magnetic fields due to the breaking of the conformal invariance in the electromagnetic field through the $CPT$-even dimension-six Chern-Simons-like effective interaction with a fermion current in…

Astrophysics · Physics 2008-12-18 K. Bamba , C. Q. Geng , S. H. Ho

Primordial magnetic fields seem to be a generic relic of phase transitions in the early universe. We consider a primordial electromagnetic field formed as a result of a second-order phase transition, and show that it is stable to thermal…

Astrophysics · Physics 2016-08-30 A. P. Martin , A. C. Davis

Using lattice techniques we investigate the generation of long range cosmological magnetic fields during a cold electroweak transition. We will show how magnetic fields arise, during bubble collisions, in the form of magnetic strings. We…

High Energy Physics - Lattice · Physics 2009-04-14 A. Diaz-Gil , J. Garcia-Bellido , M. Garcia Perez , A. Gonzalez-Arroyo

The origin of large scale magnetic fields in the Universe is widely thought to be from early Universe processes, like inflation or phase transitions. These magnetic fields evolve via magnetohydrodynamic processes until the epoch of…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-04 Molly Abramson , Emma Clarke , Tina Kahniashvili , Sayan Mandal , Salome Mtchedlidze , Jennifer Schober

The origin of our universe's cosmological magnetic fields remains a mystery. In this study, we consider whether these magnetic fields could have been generated in the early universe by a population of charged, spinning primordial black…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Dan Hooper , Aurora Ireland , Gordan Krnjaic

A generation of magnetic fields from cosmological density perturbations is investigated. In the primordial plasma before cosmological recombination, all of the materials except dark matter in the universe exist in the form of photons,…

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…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-02 Hossein Bazrafshan Moghaddam , Evan McDonough , Ryo Namba , Robert H. Brandenberger

Motivated by a scenario of magnetogenesis in which a homogeneous magnetic field is generated during inflation, we study the magnetohydrodynamic evolution of the primordial plasma motions for two kinds of initial conditions -- (i) a…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-28 Axel Brandenburg , Ruth Durrer , Yiwen Huang , Tina Kahniashvili , Sayan Mandal , Shinji Mukohyama

A completely new mechanism to generate the observed amount of large-scale cosmological magnetic fields is introduced in the context of three-form inflation. The amplification of the fields occurs via fourth order dynamics of the vector…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-17 Tomi S. Koivisto , Federico R. Urban

There is an observational indication of extragalactic magnetic fields. No known astrophysical process can explain the origin of such large scale magnetic fields, which motivates us to look for their origin in primordial inflation. By…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Teruaki Suyama , Jun'ichi Yokoyama

Generation of large-scale magnetic fields is studied in dilaton electromagnetism in noncommutative inflationary cosmology, taking into account the effects of the spacetime uncertainty principle motivated by string theory. We show that it is…

High Energy Physics - Phenomenology · Physics 2007-05-23 Kazuharu Bamba , J. Yokoyama

Magnetic fields appear wherever plasma and currents can be found. As such, they thread through all scales in Nature. It is natural, therefore, to suppose that magnetic fields might have been formed within the high temperature environments…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-16 Dai G. Yamazaki , Toshitaka Kajino , Grant J. Mathew , Kiyotomo Ichiki

Primordial magnetic fields possibly generated in the very early universe are one of the candidates for the origin of magnetic fields observed in many galaxies and galaxy clusters. After recombination, the dissipation process of the…

Astrophysics · Physics 2009-11-11 Hiroyuki Tashiro , Naoshi Sugiyama

We estimate the strength of large-scale magnetic fields produced during inflation in the framework of Dirac-Born-Infeld (DBI) theories. This analysis is sufficiently general in the sense that it covers most of conformal symmetry breaking…

Astrophysics · Physics 2010-05-12 Kazuharu Bamba , Nobuyoshi Ohta , Shinji Tsujikawa

A new generation mechanism of the magnetic field in an inhomogeneous collisionless plasma with a beam component is proposed. We show that even though the current and charge neutralities are initially satisfied, the current neutrality is…

High Energy Astrophysical Phenomena · Physics 2020-06-17 Yutaka Ohira