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Related papers: A Holographic Bound on Cosmic Magnetic Fields

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Due to quantum fluctuations, spacetime is foamy on small scales. For maximum spatial resolution of the geometry of spacetime, the holographic model of spacetime foam stipulates that the uncertainty or fluctuation of distance $l$ is given,…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Michele Arzano , Thomas W. Kephart , Y. Jack Ng

A three-dimensional (3D) MHD model is applied to simulate the evolution of a large-scale magnetic field in a barred galaxy possessing a gaseous halo extending to about 2.8 kpc above the galactic plane. As the model input we use a…

Astrophysics · Physics 2009-11-07 K. Otmianowska-Mazur , D. Elstner , M. Soida , M. Urbanik

If a magnetic field is frozen into a plasma that undergoes spherical compression then the magnetic field B varies with the plasma density \rho according to B \propto \rho^{2/3}. In the gravitational collapse of cosmological density…

Astrophysics · Physics 2007-05-23 Emma J. King , Peter Coles

Magnetic fields are involved in every astrophysical process on every scale: from planetary and stellar interiors to neutron stars, stellar wind bubbles and supernova remnants; from the interstellar medium in galactic disks, nuclei, spiral…

It is generally expected that heavy fields are present during inflation, which can leave their imprint in late-time cosmological observables. The main signature of these fields is a small amount of distinctly shaped non-Gaussianity, which…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-05 P. Daniel Meerburg , Moritz Münchmeyer , Julian B. Muñoz , Xingang Chen

Magnetic fields of laboratory, planetary, stellar, and galactic plasmas commonly exhibit significant order on large temporal or spatial scales compared to the otherwise random motions within the hosting system. Such ordered fields can be…

Solar and Stellar Astrophysics · Physics 2015-06-18 Eric G. Blackman

As well known, magnetic fields in space are distributed very inhomogeneously. Some-times field distributions have forms of filaments with high magnetic field values. As many ob-servations show, such a filamentation takes place in convective…

Solar and Stellar Astrophysics · Physics 2024-03-03 Evgeny A. Kuznetsov , Evgeny A. Mikhailov

Even though magnetic fields play an important role in galaxy evolution, the redshift evolution of galactic-scale magnetic fields is not well constrained observationally. In this paper we aim to provide an observational constraint on the…

Astrophysics of Galaxies · Physics 2025-07-18 Timea Orsolya Kovacs , Sui Ann Mao , Aritra Basu , Yik Ki Ma , B. M. Gaensler

As additional perturbative degrees of freedom, it is known that magnetic fields of inflationary origin can source curvature perturbations on super-Hubble scales. By requiring the magnetic generated curvature to remain smaller than its…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Christophe Ringeval , Teruaki Suyama , Jun'ichi Yokoyama

Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the Cosmic Microwave Background (CMB in what follows). For the first time, a consistent numerical approach to the…

Astrophysics · Physics 2010-04-29 Massimo Giovannini , Kerstin E. Kunze

The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It has…

We search for observational signatures of magnetic helicity in data from all-sky radio polarization surveys of the Milky Way Galaxy. Such a detection would help confirm the dynamo origin of the field and may provide new observational…

Astrophysics of Galaxies · Physics 2020-10-14 J. L. West , R. N. Henriksen , K. Ferrière , A. Woodfinden , T. Jaffe , B. M. Gaensler , J. A. Irwin

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,…

The origin of the first magnetic fields in the Universe is a standing problem in cosmology. Intergalactic magnetic fields (IGMFs) may be an untapped window to the primeval Universe, providing further constrains on magnetogenesis. We…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-07 Rafael Alves Batista , Andrey Saveliev

It is argued that the entropy bound places an upper limit of about 1 TeV on the temperature of the last reheating era in the early Universe. Implications for inflation and non-standard paradigms for beyond the standard model of hot…

High Energy Physics - Theory · Physics 2012-08-20 Mahdi Torabian

The dynamics of magnetic fields with amplitude of several tens of Megagauss, generated at both sides of a solid target irradiated with a high intensity (? 1019W/cm2) picosecond laser pulse, has been spatially and temporally resolved using a…

In holographic inflation, the $4D$ cosmological dynamics is postulated to be dual to the renormalization group flow of a $3D$ Euclidean conformal field theory with marginally relevant operators. The scalar potential of the $4D$ theory ---in…

High Energy Physics - Theory · Physics 2019-05-22 Ana Achucarro , Sebastian Cespedes , Anne-Christine Davis , Gonzalo A. Palma

Using cosmological MHD simulations of the magnetic field in galaxy clusters and filaments we evaluate the possibility to infer the magnetic field strength in filaments by measuring cross-correlation functions between Faraday Rotation…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 F. Stasyszyn , S. E. Nuza , K. Dolag , R. Beck , J. Donnert

We explore the amplification of magnetic fields in the high-redshift Universe. For this purpose, we perform high-resolution cosmological simulations following the formation of primordial halos with \sim10^7 M_solar, revealing the presence…

We present a new cosmological model, based on the holographic principle, which shares many of the virtues of inflation. The very earliest semiclassical era of the universe is dominated by a dense gas of black holes, with equation of state…

High Energy Physics - Theory · Physics 2007-05-23 T. Banks , W. Fischler