scholarly journals Metric-affine bumblebee gravity: classical aspects

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Adrià Delhom ◽  
J. R. Nascimento ◽  
Gonzalo J. Olmo ◽  
A. Yu. Petrov ◽  
Paulo J. Porfírio
Keyword(s):  
Physical Properties ◽  
Weak Field ◽  
The Other ◽  
Effective Theory ◽  
Field Equations ◽  
Field Limit ◽  
Weak Field Limit ◽  
Effective Metric ◽  
The Stability ◽  
Matter Fields

AbstractWe consider the metric-affine formulation of bumblebee gravity, derive the field equations, and show that the connection can be written as Levi-Civita of a disformally related metric in which the bumblebee field determines the disformal part. As a consequence, the bumblebee field gets coupled to all the other matter fields present in the theory, potentially leading to nontrivial phenomenological effects. To explore this issue we compute the post-Minkowskian, weak-field limit and study the resulting effective theory. In this scenario, we couple scalar and spinorial matter to the effective metric, and then we explore the physical properties of the VEV of the bumblebee field, focusing mainly on the dispersion relations and the stability of the resulting effective theory.

scholarly journals Weak field limit and gravitational waves in f(T, B) teleparallel gravity

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Salvatore Capozziello ◽  
Maurizio Capriolo ◽  
Loredana Caso
Keyword(s):  
Gravitational Waves ◽  
Teleparallel Gravity ◽  
Weak Field ◽  
Massive Scalar ◽  
Tensor Polarization ◽  
Field Equations ◽  
Field Limit ◽  
Weak Field Limit ◽  
Limit Approximation ◽  
Scalar Mode

Abstract We derive the gravitational waves for $$f\left( T, B\right) $$fT,B gravity which is an extension of teleparallel gravity and demonstrate that it is equivalent to f(R) gravity by linearized the field equations in the weak field limit approximation. f(T, B) gravity shows three polarizations: the two standard of general relativity, plus and cross, which are purely transverse with two-helicity, massless tensor polarization modes, and an additional massive scalar mode with zero-helicity. The last one is a mix of longitudinal and transverse breathing scalar polarization modes. The boundary term B excites the extra scalar polarization and the mass of scalar field breaks the symmetry of the TT gauge by adding a new degree of freedom, namely a single mixed scalar polarization.

Gravity as a gauge theory

2018 ◽  
Author(s):  
Michael Kachelriess
Keyword(s):  
Gauge Theory ◽  
Weak Field ◽  
Einstein Equations ◽  
Field Equations ◽  
Field Limit ◽  
Weak Field Limit ◽  
Standard Formalism

The vielbein formalism is developed as a tool to determine the coupling of matter to gravity. After determining the relation to the standard formalism, the action and the field equations of gravity are introduced. The linearised Einstein equations which describe the weak-field limit of gravity are derived.

scholarly journals Dark Matter as Gravitational Solitons in the Weak Field Limit

Universe ◽  
2020 ◽  
Vol 6 (12) ◽  
pp. 234
Author(s):  
Torsten Asselmeyer-Maluga ◽  
Jerzy Król
Keyword(s):  
Dark Matter ◽  
Equation Of State ◽  
Gravitational Lensing ◽  
Weak Field ◽  
Field Limit ◽  
Gravitational Fields ◽  
Weak Field Limit ◽  
Lensing Effect ◽  
The Stability

In this paper, we will describe the idea that dark matter partly consists of gravitational solitons (gravisolitons). The corresponding solution is valid for weak gravitational fields (weak field limit) with respect to a background metric. The stability of this soliton is connected with the existence of a special foliation and amazingly with the smoothness properties of spacetime. Gravisolitons have many properties of dark matter, such as no interaction with light but act on matter via gravitation. In this paper, we showed that the gravitational lensing effect of gravisolitons agreed with the lensing effect of usual matter. Furthermore, we obtained the same equation of state w=0 as matter.

GALACTIC AND ASTROPHYSICAL SIZES FROM SCALAR-TENSOR THEORY OF GRAVITY

2004 ◽  
Vol 13 (02) ◽  
pp. 359-371 ◽  
Author(s):  
GIUSEPPE BASINI ◽  
MARCO RICCI ◽  
FULVIO BONGIORNO ◽  
SALVATORE CAPOZZIELLO
Keyword(s):  
Scalar Field ◽  
Spiral Galaxies ◽  
Weak Field ◽  
Newtonian Potential ◽  
Scalar Tensor Theory ◽  
Field Limit ◽  
Weak Field Limit ◽  
Tensor Theory ◽  
Flat Rotation Curves ◽  
Theory Of Gravity

We investigate the weak-field limit of scalar-tensor theory of gravity and show that results are directly depending on the coupling and self-interaction potential of the scalar field. In particular, corrections are derived for the Newtonian potential. We discuss astrophysical applications of the results, in particular the flat rotation curves of spiral galaxies.

scholarly journals Quantum Faraday Effect in the Universe

2017 ◽  
Vol 45 ◽  
pp. 1760046
Author(s):  
Lídice Cruz Rodríguez ◽  
Aurora Pérez Martínez ◽  
Gabriella Piccinelli ◽  
Elizabeth Rodríguez Querts
Keyword(s):  
Faraday Effect ◽  
Weak Field ◽  
Field Limit ◽  
Self Energy ◽  
Weak Field Limit ◽  
Resonant Behavior ◽  
Degenerate Regime ◽  
The Universe ◽  
Resonant Mechanism ◽  
Recombination Epoch

We study the Quantum Faraday rotation starting from the photon self-energy in the presence of a constant magnetic field. The Faraday angle is calculated in the non-degenerate regime and for weak field limit. Two physical scenarios, possibly characterized by these conditions, are the recombination epoch and the jets originated in pulsars. We discuss the resonant behavior that the Faraday angle exhibits in these scenarios and investigate the possibility of detecting cosmic magnetic fields through this resonant mechanism.

Weak-field limit

2010 ◽  
pp. 165-208
Author(s):  
Salvatore Capozziello ◽  
Valerio Faraoni
Keyword(s):  
Weak Field ◽  
Field Limit ◽  
Weak Field Limit

scholarly journals Jeans instability in non-minimal matter-curvature coupling gravity

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Cláudio Gomes
Keyword(s):  
Boltzmann Equation ◽  
Dispersion Relation ◽  
Weak Field ◽  
Model Parameters ◽  
Field Limit ◽  
Modified Dispersion Relation ◽  
Weak Field Limit ◽  
Special Cases ◽  
Jeans Instability ◽  
Scalar Potentials

Abstract The weak field limit of the nonminimally coupled Boltzmann equation is studied, and relations between the invariant Bardeen scalar potentials are derived. The Jean’s criterion for instabilities is found through the modified dispersion relation. Special cases are scrutinised and considerations on the model parameters are discussed for Bok globules.

scholarly journals Weak field limit of higher dimensional massive Brans-Dicke gravity: Observational constraints

2020 ◽  
Vol 101 (2) ◽  
Author(s):  
Özgür Akarsu ◽  
Alexey Chopovsky ◽  
Valerii Shulga ◽  
Ezgi Yalçınkaya ◽  
Alexander Zhuk
Keyword(s):  
Weak Field ◽  
Observational Constraints ◽  
Field Limit ◽  
Weak Field Limit ◽  
Higher Dimensional
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