scholarly journals Modified scalar-tensor-vector gravity theory and the constraint on its parameters

2009 ◽  
Vol 79 (4) ◽  
Author(s):  
Xue-Mei Deng ◽  
Yi Xie ◽  
Tian-Yi Huang
Keyword(s):  
Gravity Theory

A Gravity Theory on Noncommutative Spaces

2007 ◽  
Author(s):  
Frank Meyer ◽  
P. Aschieri ◽  
C. Blohmann ◽  
M. Dimitrijevic ◽  
P. Schupp ◽  
...  
Keyword(s):  
Gravity Theory ◽  
Noncommutative Spaces

scholarly journals Gravitational waves in metric-affine gravity theory

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
Alejandro Jiménez-Cano ◽  
Yuri N. Obukhov
Keyword(s):  
Gravitational Waves ◽  
Gravity Theory ◽  
Affine Gravity

scholarly journals Bianchi I metric solutions with nonminimally coupled Einstein–Maxwell gravity theory

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Hossein Ghaffarnejad ◽  
Hoda Gholipour
Keyword(s):  
Gravity Theory ◽  
Bianchi I

Cosmological inflation in f(X) gravity theory

2019 ◽  
Vol 26 ◽  
pp. 100401 ◽  
Author(s):  
Hafiza Rizwana Kausar ◽  
Rabia Saleem ◽  
Amara Ilyas
Keyword(s):  
Gravity Theory ◽  
Cosmological Inflation

Three classical tests of Hořava-Lifshitz gravity theory

2011 ◽  
Vol 337 (2) ◽  
pp. 779-784 ◽  
Author(s):  
Shi-Wei Zhou ◽  
Wen-Biao Liu
Keyword(s):  
Gravity Theory

scholarly journals On Quantum Cosmology of the R2 Gravity Theory

2014 ◽  
Vol 6 (3) ◽  
Author(s):  
Mohamed A. Ahmed
Keyword(s):  
Quantum Cosmology ◽  
Gravity Theory

CLASSICAL INSTABILITY OF THE EINSTEIN-GAUSS-BONNET GRAVITY THEORY WITH COMPACTIFIED HIGHER DIMENSIONS

1991 ◽  
Vol 06 (25) ◽  
pp. 4517-4555 ◽  
Author(s):  
LESZEK M. SOKOŁOWSKI ◽  
ZDZISŁAW A. GOLDA ◽  
MARCO LITTERIO ◽  
LUCA AMENDOLA
Keyword(s):  
Scalar Fields ◽  
Gravity Theory ◽  
Effective Theory ◽  
Internal Space ◽  
Bonnet Gravity ◽  
Four Dimensions ◽  
Effective Gravity ◽  
Tensor Theory ◽  
Exciting System ◽  
Bonnet Term

The energy spectrum and stability of the effective theory resulting from the Einstein-Gauss-Bonnet gravity theory with compactified internal space are investigated. The internal space can evolve in its volume and/or shape, giving rise to a system of scalar fields in the external space-time. The resulting scalar-tensor theory of gravity has physically unacceptable properties. First of all, the scalar fields’ energy is indefinite and unbounded from below, and thereby the gravitational and scalar fields form a self-exciting system. In contradistinction to the case of multidimensional Einstein gravity, this inherent instability of the effective theory cannot be removed by field redefinitions in the process of dimensional reduction (e.g. by a conformal rescaling of the metric in four dimensions, as is done in the former case). To get a viable effective gravity theory one should discard either the geometric scalar fields or the Gauss-Bonnet term from the Lagrangian of the multidimensional theory. It is argued that it is the Gauss-Bonnet term that should be discarded.

scholarly journals Los principios de la relatividad: una introducci´on pedag´ogica

2018 ◽  
Vol 64 (1) ◽  
pp. 87
Author(s):  
Y. Bonder ◽  
E. Okon
Keyword(s):  
Quantum Gravity ◽  
Gravity Theory ◽  
Theory Of Relativity

The principles underlying the theory of relativity, special and general, are presented. An easy to follow and pedagogical language is used and, based on physical examples, the motivation and some consequences of such principles are discussed. In addition, some roles of these principles when looking for a quantum gravity theory are mentioned

scholarly journals Gödel and Gödel-type solutions in the Palatini f(R,T) gravity theory

2020 ◽  
pp. 2150014
Author(s):  
J. S. Gonçalves ◽  
A. F. Santos
Keyword(s):  
Trace Formula ◽  
Arbitrary Function ◽  
Critical Radius ◽  
Energy Momentum Tensor ◽  
Gravitational Theory ◽  
Momentum Tensor ◽  
Gravity Theory ◽  
Ricci Scalar ◽  
Independent Variables ◽  
Hilbert Action

The Palatini [Formula: see text] gravity theory is considered. The standard Einstein–Hilbert action is replaced by an arbitrary function of the Ricci scalar [Formula: see text] and of the trace [Formula: see text] of the energy-momentum tensor. In the Palatini approach, the Ricci scalar is a function of the metric and the connection. These two quantities, metric and connection, are taken as independent variables. Then, it is examined whether Palatini [Formula: see text] gravity theory allows solutions in which lead to violation of causality. The Gödel and Gödel-type spacetimes are considered. In addition, a critical radius, which permits to examine limits for violation of causality, is calculated. It is shown that, for different matter contents, noncausal solutions can be avoided in this Palatini gravitational theory.

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