scholarly journals Weak field limit and gravitational waves in higher-order gravity

2019 ◽  
Vol 16 (03) ◽  
pp. 1950047 ◽  
Author(s):  
Salvatore Capozziello ◽  
Maurizio Capriolo ◽  
Loredana Caso
Keyword(s):  
Gravitational Waves ◽  
Order Term ◽  
Normal Modes ◽  
Weak Field ◽  
Higher Order ◽  
Field Limit ◽  
Weak Field Limit ◽  
Higher Order Gravity ◽  
Higher Order Derivative ◽  
Effective Theories

We derive the weak field limit for a gravitational Lagrangian density [Formula: see text], where higher-order derivative terms in the Ricci scalar [Formula: see text] are taken into account. The interest for this kind of effective theories comes out from the consideration of the infrared and ultraviolet behaviors of gravitational field and, in general, from the formulation of quantum field theory in curved spacetimes. Here, we obtain solutions in weak field regime both in vacuum and in the presence of matter and derive gravitational waves considering the contribution of [Formula: see text] terms. By using a suitable set of coefficients [Formula: see text], it is possible to find up to [Formula: see text] normal modes of oscillation with six polarization states with helicity 0 or 2. Here [Formula: see text] is the higher-order term in the [Formula: see text] operator appearing in the gravitational Lagrangian. More specifically: the mode [Formula: see text], with [Formula: see text], has transverse polarizations [Formula: see text] and [Formula: see text] with helicity 2; the [Formula: see text] modes [Formula: see text], with [Formula: see text], have transverse polarizations [Formula: see text] and non-transverse ones [Formula: see text], [Formula: see text], [Formula: see text] with helicity 0.

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.

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

scholarly journals GRAVITATIONAL LENSING IN THE WEAK FIELD LIMIT BY A BRANEWORLD BLACK HOLE

2005 ◽  
Vol 20 (32) ◽  
pp. 2487-2496 ◽  
Author(s):  
A. S. MAJUMDAR ◽  
NUPUR MUKHERJEE
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Lensing ◽  
Cosmic Ray ◽  
Weak Field ◽  
High Energy ◽  
High Energy Particle ◽  
Field Limit ◽  
Weak Field Limit ◽  
Point Light

The existence of braneworld black holes may be of primordial origin, or may even be produced in high energy particle collisions in the laboratory and in cosmic ray showers as well. These black holes obey a modified mass–radius relationship compared to standard Schwarzschild black holes. Using the variational principle we calculate the bending angle of a light ray near the horizon of a braneworld black hole in the weak field limit. We next derive the expressions of several lensing quantities like the Einstein radius and the magnification for a point light source. These expressions are modified compared to the lensing quantities for standard Schwarzschild black holes and contain the scale of the extra dimensions.

Sign in / Sign up

Export Citation Format

Share Document