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Related papers: Charge Enhancement of Noncommutative Gravity

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Starting from Jefimenko's equations, we consider the multipole expansions of electric and magnetic fields for a confined system of charges and currents. We analyze and comment on the calculus of radiated power, on the consistent use of…

Classical Physics · Physics 2009-10-08 C. Vrejoiu , R. Zus

The main contribution to the pulsar power can be calculated by assuming a rotating magnetically-dominated magnetosphere described by the force-free approximation. Although this simple model has been used thoroughly to study pulsar…

High Energy Astrophysical Phenomena · Physics 2018-07-18 Federico Carrasco , Carlos Palenzuela , Oscar Reula

In this paper, we investigate the effects of electromagnetic field on the isotropic spherical gravastar models in metric $f(R,T)$ gravity. For this purpose, we have explored singularity-free exact models of relativistic spheres with a…

General Relativity and Quantum Cosmology · Physics 2020-03-03 Z. Yousaf , Kazuharu Bamba , M. Z. Bhatti , U. Ghafoor

We search for viable f(R) theories of gravity, making use of the equivalence between such theories and scalar-tensor gravity. We find that models can be made consistent with solar system constraints either by giving the scalar a high mass…

Astrophysics · Physics 2008-11-26 Thomas Faulkner , Max Tegmark , Emory F. Bunn , Yi Mao

We consider inflation within the context of what is arguably the simplest non-metric extension of Einstein gravity. There non-metricity is described by a single graviscalar field with a non-minimal kinetic coupling to the inflaton field…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Kari Enqvist , Tomi Koivisto , Gerasimos Rigopoulos

Modified gravity theories have richer observational consequences for large-scale structure than conventional dark energy models, in that different observables are not described by a single growth factor even in the linear regime. We examine…

Astrophysics · Physics 2009-02-20 Bhuvnesh Jain , Pengjie Zhang

In a modified gravity theory, the propagation equation of gravitational waves will be presented in a non-standard way. Therefore this tenor mode perturbation of time-space, as a complement to the scalar mode perturbation, provides a unique…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Lixin Xu

This is an introduction to an algebraic construction of a gravity theory on noncommutative spaces which is based on a deformed algebra of (infinitesimal) diffeomorphisms. We start with some fundamental ideas and concepts of noncommutative…

High Energy Physics - Theory · Physics 2007-05-23 Frank Meyer

We explore the weak-field phenomenology of a compact star spacetime modified by quantum gravitational corrections derived from the effective field theoretical (EFT) approach by Calmet et al. [1]. These corrections, encoded in non-local…

General Relativity and Quantum Cosmology · Physics 2026-02-10 Reggie C. Pantig , Ali Ovgun , Gaetano Lambiase

Searches for empirical clues beyond Einstein's general relativity (GR) are crucial to understand gravitation and spacetime. Radio pulsars have been playing an important role in testing gravity theories since 1970s. Because radio timing of…

General Relativity and Quantum Cosmology · Physics 2023-05-16 Lijing Shao

The recent observation of high-energy astrophysical neutrinos can be used to constrain violations of Lorentz invariance emerging from a quantum theory of gravity. We perform threshold and Cherenkov analyses that improve existing bounds by…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Jorge S. Diaz , Alan Kostelecky , Matthew Mewes

Starting with an entropy that includes volumetric, area and length terms as well as logarithmic contributions, we derive the corresponding modified Newtonian gravity and derive the expression for planetary orbits. We calculate the shift of…

General Relativity and Quantum Cosmology · Physics 2021-06-18 G. Pérez-Cuéllar , M. Sabido

Complete flavour decompositions of the scalar, axial and tensor charges of the proton, deuteron, diproton and $^3$He at SU(3)-symmetric values of the quark masses corresponding to a pion mass $m_\pi\sim806$ MeV are determined using lattice…

Current astrophysical observations show that on large scale the Universe is electrically neutral. However, locally this may be quite different. Black holes enveloped by a plasma in the presence of a strong magnetic field may have acquired a…

General Relativity and Quantum Cosmology · Physics 2023-04-04 Torben C. Frost

Pulsar-timing has become a celebrated tool for probing modifications to General Relativity in the strong-field surroundings of neutron stars. Here we investigate whether scalar-tensor theories that incorporate a nonminimally coupled scalar…

General Relativity and Quantum Cosmology · Physics 2019-06-19 Raissa F. P. Mendes , Tulio Ottoni

The modified gravity, which eliminates the need for dark energy and which seems to be stable, is considered. The terms with positive powers of the curvature support the inflationary epoch while the terms with negative powers of the…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

Higher-curvature corrections to the effective gravitational action may leave signatures in the spectrum of primordial tensor perturbations if the inflationary energy scale is sufficiently high. In this paper we further investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-15 William Giarè , Fabrizio Renzi , Alessandro Melchiorri

We investigate the effect of a strong magnetic field on the structure of neutron stars in a model with perturbative $f(R)$ gravity. The effect of an interior strong magnetic field of about $10^{17 \sim 18}$ G on the equation of state is…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Myung-Ki Cheoun , Cemsinan Deliduman , Can Güngör , Vildan Keleş , C. Y. Ryu , Toshitaka Kajino , Grant J. Mathews

Here we present an overview on the various works, in which many collaborators have contributed, regarding the interesting dipole of noncommutativity and physics. In brief, we present the features that noncommutativity triggers both in the…

High Energy Physics - Theory · Physics 2023-05-22 George Manolakos , Pantelis Manousselis , Danai Roumelioti , Stelios Stefas , George Zoupanos

We study the influence of the spacetime noncommutative parameter on the strong field gravitational lensing in the noncommutative Reissner-Nordstr\"{o}m black-hole spacetime. Supposing that the gravitational field of the supermassive central…

General Relativity and Quantum Cosmology · Physics 2011-10-14 Chikun Ding , Jiliang Jing