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Magnetic fields in various astrophysical settings may be helical and, in the cosmological context, may provide a measure of primordial CP violation during baryogenesis. Yet it is difficult, even in principle, to devise a scheme by which…

Astrophysics · Physics 2009-11-13 Tina Kahniashvili , Tanmay Vachaspati

In the present work, we have studied the spectrum of the primordial gravitational waves due to magnetic instability in the presence of neutrino asymmetry. The magnetic instability generates a helical magnetic field on a large scale. The…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-23 Arun Kumar Pandey , Pravin Kumar Natwariya , Jitesh R Bhatt

Spontaneous breaking of Lorentz invariance compatible with observational limits may realistically take place in the context of string theories, possibly endowing the photon with a mass. In this process the conformal symmetry of the…

General Relativity and Quantum Cosmology · Physics 2016-08-31 O. Bertolami , D. F. Mota

It is known that cosmic magnetic field, if present, can generate anisotropic stress in the plasma and hence, can act as a source of gravitational waves. These cosmic magnetic fields can be generated at very high temperature, much above…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-25 Sampurn Anand , Jitesh R. Bhatt , Arun Kumar Pandey

The Hofstadter problem is the lattice analog of the quantum Hall effect and is the paradigmatic example of topology induced by an applied magnetic field. Conventionally, the Hofstadter problem involves adding $\sim 10^4$ T magnetic fields…

Mesoscale and Nanoscale Physics · Physics 2020-12-30 Jonah Herzog-Arbeitman , Zhi-Da Song , Nicolas Regnault , B. Andrei Bernevig

In this work we consider the most general electromagnetic theory in curved space-time leading to linear second order differential equations, including non-minimal couplings to the space-time curvature. We assume the presence of a temporal…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Jose Beltran Jimenez , Antonio L. Maroto

We compute the generation of vorticity from velocity dispersion in the dark matter fluid. For dark matter at zero temperature Helmholtz's theorem dictates that no vorticity is generated and we therefore allow the dark matter fluid to have a…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-05 Giulia Cusin , Vittorio Tansella , Ruth Durrer

Magnetorotational Instability (MRI), the instability causing turbulent transport in accretion disks, is studied in the kinetic regime. Radiatively Inefficient Accretion Flows (RIAFs), like the one around the supermassive black hole in the…

Astrophysics · Physics 2007-05-23 Prateek Sharma

We study a holographic model with vector condensate by coupling the anti-de Sitter gravity to an Abelian gauge field and a charged vector field in $(3+1)$ dimensional spacetime. In this model there exists a non-minimal coupling of the…

High Energy Physics - Theory · Physics 2014-01-27 Rong-Gen Cai , Song He , Li Li , Li-Fang Li

The chiral magnetic and vortical effects denote the generation of dissipationless currents due to magnetic fields or rotation. They can be studied in holographic models with Chern-Simons couplings dual to anomalies in field theory. We study…

High Energy Physics - Theory · Physics 2017-09-20 Christian Copetti , Jorge Fernández-Pendás , Karl Landsteiner , Eugenio Megías

We have tested the ability of driven turbulence to generate magnetic field structure from a weak uniform field using three dimensional numerical simulations of incompressible turbulence. We used a pseudo-spectral code with a numerical…

Astrophysics · Physics 2009-10-31 Jungyeon Cho , Ethan T. Vishniac

Electric field control of magnetic structures, particularly topological defects in magnetoelectric materials, draws a great attention in recent years, which has led to experimental success in creation and manipulation by electric field of…

Strongly Correlated Electrons · Physics 2017-05-24 P. I. Karpov , S. I. Mukhin

We reexamine generation of the primordial magnetic fields, at temperature $T>80$TeV, by applying a consistent kinetic theory framework which is suitably modified to take the quantum anomaly into account. The modified kinetic equation can…

General Relativity and Quantum Cosmology · Physics 2016-09-01 Arun Kumar Pandey , Jitesh R. Bhatt

Magnetic fields of cosmic bodies are generated by the hydromagnetic dynamo effect in moving electrically conducting fluids, such as liquid metals or plasmas. Once produced, cosmic magnetic fields are able to act back on moving fluids. This…

History and Philosophy of Physics · Physics 2014-03-17 Frank Stefani

It is shown that the magnetic current-driven (`kink-type') instability produces flow and field patterns with helicity and even with \alpha-effect but only if the magnetic background field possesses non-vanishing current helicity…

Solar and Stellar Astrophysics · Physics 2015-05-20 Guenther Ruediger , Marcus Gellert , Rainer Arlt

The perturbation of a magnetostatic field by a toroid made of a homogeneous anisotropic magnetic material was formulated using the solutions of the Laplace equation in the toroidal coordinate system. That was straightforward in the region…

Classical Physics · Physics 2025-04-11 Hamad M. Alkhoori , Akhlesh Lakhtakia , Nikolaos L. Tsitsas

To find out whether toroidal field can stably exist in galaxies the current-driven instability of toroidal magnetic fields is considered under the influence of an axial magnetic field component and under the influence of both rigid and…

Astrophysics of Galaxies · Physics 2015-05-19 G. Ruediger , M. Schultz , D. Elstner

Dyonic and magnetic black holes solutions with spherically symmetric configurations in general relativity are obtained. Black holes possessing electric and magnetic charges are studied where the source of the gravitational field is…

General Relativity and Quantum Cosmology · Physics 2019-11-12 S. I. Kruglov

The origin of large scale cosmological magnetic fields remains a mystery, despite the continuous efforts devoted to that problem. We present a new model of magnetic field generation, based on local charge separation provided by an…

Astrophysics · Physics 2009-04-16 Mathieu Langer , Jean-Loup Puget , Nabila Aghanim

Helicity and \alpha effect driven by the nonaxisymmetric Tayler instability of toroidal magnetic fields in stellar radiation zones are computed. In the linear approximation a purely toroidal field always excites pairs of modes with…

Solar and Stellar Astrophysics · Physics 2015-05-28 G. Ruediger , L. L. Kitchatinov , D. Elstner