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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

Generation of large-scale magnetic fields in inflationary cosmology is studied in teleparallelism, where instead of the scalar curvature in general relativity, the torsion scalar describes the gravity theory. In particular, we investigate a…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-26 Kazuharu Bamba , Chao-Qiang Geng , Ling-Wei Luo

The property of the spectrum of large-scale magnetic fields generated due to the breaking of the conformal invariance of the Maxwell theory through some mechanism in inflationary cosmology is studied. It is shown that the spectrum of the…

Astrophysics · Physics 2008-11-26 Kazuharu Bamba

The interrelation between the generation of large-scale electric fields and that of large-scale magnetic fields due to the breaking of the conformal invariance of the electromagnetic field in inflationary cosmology is studied. It is shown…

Astrophysics · Physics 2009-06-23 Kazuharu Bamba

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

The generation of large-scale magnetic fields is studied in dilaton electromagnetism in inflationary cosmology, taking into account the dilaton's evolution throughout inflation and reheating until it is stabilized with possible entropy…

Astrophysics · Physics 2008-11-26 Kazuharu Bamba , J. Yokoyama

We explore the generation of large-scale magnetic fields from inflation in teleparallelism, in which the gravitational theory is described by the torsion scalar instead of the scalar curvature in general relativity. In particular, we…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-02 Kazuharu Bamba , Chao-Qiang Geng , Ling-Wei Luo

We discuss a model which can generate scale-invariant helical magnetic fields on large scales ($\lesssim 1$Mpc) in the primordial universe. It is also shown that the electric conductivity becomes significant and terminates magnetogenesis…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-11 Tomohiro Fujita , Ruth Durrer

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-30 Kazuharu Bamba

The 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…

High Energy Physics - Phenomenology · Physics 2009-11-10 Kazuharu Bamba , J. Yokoyama

We consider several gauge invariant higher dimensional operators that couple gravity, gauge fields and scalar or fermionic fields and thus break conformal invariance. In particular, we consider terms that break conformal invariance by the…

Astrophysics · Physics 2007-05-23 Tomislav Prokopec

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

The generation of large-scale magnetic fields in inflationary cosmology is explored, in particular, in a kind of moduli inflation motivated by racetrack inflation in the context of the Type IIB string theory. In this model, the conformal…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Kazuharu Bamba

We propose a new mechanism for magnetic field generation from inflation, by which strong magnetic fields can be generated on cosmological scales. These fields may be observable by cosmic microwave background radition measurements, and may…

Astrophysics · Physics 2009-11-10 Tomislav Prokopec , Ewald Puchwein

We study the CPT-even dimension-six Chern-Simons-like term by including dynamical Kalb-Ramond and scalar fields to examine the cosmological birefringence. We show that the combined effect of neutrino current and Kalb-Ramond field could…

High Energy Physics - Phenomenology · Physics 2010-08-04 Shih-Hao Ho , W. F. Kao , Kazuharu Bamba , C. Q. Geng

If the conformal invariance of electromagnetism is broken during inflation, then primordial magnetic fields may be produced. If this symmetry breaking is generated by the coupling between electromagnetism and a scalar field---e.g. the…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-29 Robert R. Caldwell , Leonardo Motta , Marc Kamionkowski

Any attempt to understand the ubiquitous nature of the magnetic field in the present universe seems to lead us towards its primordial origin. For large-scale magnetic fields, however, their strength and length scale may not necessarily…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-01 Subhasis Maiti , Debaprasad Maity , Rohan Srikanth

We investigate the generation of large scale magnetic fields in the universe from quantum fluctuations produced in the inflationary stage. By coupling these quantum fluctuations to the dilaton field and Ricci scalar, we show that the…

Astrophysics · Physics 2008-11-26 A. Akhtari Zavareh , A. Hojjati , B. Mirza

We compute the contribution to the scalar metric perturbations from large-scale magnetic fields which are generated during inflation. We show that apart from the usual passive and compensated modes, the magnetic fields also contribute to…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-01 Camille Bonvin , Chiara Caprini , Ruth Durrer

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…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-26 Leonardo Campanelli
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