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The attempt to describe the recent accelerated expansion of the Universe includes different propositions for dark energy models and modified gravity theories. Establish their features in order to discriminate and even rule out part of these…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-01 M. Penna-Lima , S. D. P. Vitenti , M. E. S. Alves , J. C. N. de Araujo , F. C. Carvalho

Over the last few years much attention has been given to the study of modified gravity theories in order to find a more natural explanation for the late time acceleration of the Universe. Nevertheless, a comparison of the matter power…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Amare Abebe , Alvaro de la Cruz Dombriz , Peter K. S. Dunsby

The effect of static electromagnetic fields on the propagation of light is analyzed in the context of a particular class of scalar-tensor gravitational theories. It is found that for appropriate field configurations and light polarization,…

General Relativity and Quantum Cosmology · Physics 2013-10-10 T. E. Raptis , F. O. Minotti

A cosmic scalar field evolving very slowly in time can account for the observed dark energy of the Universe. Unlike a cosmological constant, an evolving scalar field also has local spatial gradients due to gravity. If the scalar field has a…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-01 Michael V. Romalis , Robert R. Caldwell

Experiments are beginning to probe the interaction of quantum particles with gravitational fields beyond the uniform-field regime. In non-relativistic quantum mechanics, the gravitational field in such experiments can be written as a…

Latent space Energy-Based Models (EBMs), also known as energy-based priors, have drawn growing interests in generative modeling. Fueled by its flexibility in the formulation and strong modeling power of the latent space, recent works built…

Machine Learning · Computer Science 2023-10-06 Peiyu Yu , Sirui Xie , Xiaojian Ma , Baoxiong Jia , Bo Pang , Ruiqi Gao , Yixin Zhu , Song-Chun Zhu , Ying Nian Wu

The origin of extragalactic magnetic fields is still poorly understood. Based on a dedicated suite of cosmological magneto-hydrodynamical simulations with the ENZO code we have performed a survey of different models that may have caused…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-22 F. Vazza , M. Brüggen , C. Gheller , S. Hackstein , D. Wittor , P. M. Hinz

Earth System Models (ESM) are important tools that allow us to understand and quantify the physical, chemical & biological mechanisms governing the rates of change of elements of the Earth System, comprising of the atmosphere, ocean, land,…

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

The Lagrangian formulation of Gravitoelectromagnetism (GEM) theory is considered. GEM is a gravitational theory constructed based on the similarities between gravity and electromagnetism. In this framework, we investigate gravitational…

General Relativity and Quantum Cosmology · Physics 2025-02-20 L. A. S. Evangelista , A. F. Santos

We consider the effect of gravity on extended quantum systems (EQS) in the low energy regime. We model the gravitational effect due to a nearby source mass as a redshift in the internal Hamiltonian of the EQS. Due to the dependence of the…

Quantum Physics · Physics 2022-10-10 Harshit Verma , Magdalena Zych , Fabio Costa

We analyze cosmography as a tool to constrain modified gravity theories. We take four distinct models and obtain their parameters in terms of the cosmographic parameters favored by observational data of strong gravitational lensing. We…

General Relativity and Quantum Cosmology · Physics 2025-02-06 Mario H. Amante , Andrés Lizardo , Javier Chagoya , C. Ortiz

Theory and recent experiments concerning exchange-driven magnetic excitation (EDME) are reviewed. This phenomenon employs the exchange field produced by a narrowly distributed spin-polarized electron current to excite Larmor precession in a…

Condensed Matter · Physics 2007-05-23 J. C. Slonczewski

Modified gravitational wave propagation is a smoking gun of modifications of gravity at cosmological scales, and can be the most promising observable for testing such theories. The observation of gravitational waves (GW) in recent years has…

General Relativity and Quantum Cosmology · Physics 2022-03-18 Francesco Iacovelli , Andreas Finke , Stefano Foffa , Michele Maggiore , Michele Mancarella

A modification of the Maxwell equations due to the presence of a gravitational field was formerly proposed for a scalar theory with a preferred reference frame. With this modification, the electric charge is not conserved. The aim of the…

General Physics · Physics 2018-01-31 Mayeul Arminjon

Observational manifestations of some models of modified gravity, which have been suggested to explain the accelerated cosmological expansion, are analyzed for gravitating systems with time dependent mass density. It is shown that if the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 E. V. Arbuzova , A. D. Dolgov

An alternative for the Higgs mechanism is proposed. It predicts the appearance in the broken phase of a scalar background field which may be interpreted as describing an almost uniform (i.e., homogeneous and isotropic) superfluid condensate…

High Energy Physics - Phenomenology · Physics 2008-02-03 V. Delgado

Reconstructing the initial conditions of the universe is a key problem in cosmology. Methods based on simulating the forward evolution of the universe have provided a way to infer initial conditions consistent with present-day observations.…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-11 Ronan Legin , Matthew Ho , Pablo Lemos , Laurence Perreault-Levasseur , Shirley Ho , Yashar Hezaveh , Benjamin Wandelt

Previously we conjectured that extremely high Electromagnetic (EM) fields in a vacuum generate a gravitational field that causes Maxwell's equations to no longer be linear. This results in a "4-force" in the field configuration space, also…

General Physics · Physics 2023-12-12 Pierre Marx

We discuss the possibility that spacetime geometry may be an emergent phenomenon. This idea has been motivated by the Analogue Gravity programme. These are systems where the kinematics of small perturbations are dominated by an effective…

General Relativity and Quantum Cosmology · Physics 2007-11-29 Silke Weinfurtner
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