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We study linear cosmological perturbations in the most general teleparallel gravity setting, where gravity is mediated by the torsion and nonmetricity of a flat connection alongside the metric. For a general linear perturbation of this…

General Relativity and Quantum Cosmology · Physics 2023-12-22 Lavinia Heisenberg , Manuel Hohmann

A generalized model of space-time is given, taking into consideration the anisotropic structure of fields which are depended on the position and the direction (velocity).In this framework a generalized FRW-metric the Raychaudhouri and…

General Relativity and Quantum Cosmology · Physics 2008-11-26 P. C. Stavrinos , A. P. Kouretsis , M. Stathakopoulos

First the second-order perturbations of nonzero-\Lambda cosmological models are derived with an arbitrary potential function of spatial coordinates, using the nonlinear version of Lifshitz's method in the synchronous gauge. Their expression…

Astrophysics · Physics 2009-11-10 Kenji Tomita

We present the classical solutions to the Einstein field equations derived using the WKB-like and Hamilton procedures. The investigation is carried out in the commutative and noncommutative scenario for the Bianchi type I cosmological model…

General Relativity and Quantum Cosmology · Physics 2009-11-13 C. Ortiz , E. Mena-Barboza , M. Sabido , J. Socorro

We propose a new theory of gravitation on noncommutative space-time which is invariant under the general coordinate transformations, while the local Lorentz invariance is realized as twisted gauge symmetry. Our theory is remarkably simpler…

High Energy Physics - Theory · Physics 2010-09-29 Archil Kobakhidze

We show the existence of a noncommutative spacetime structure in the context of a complete discussion on the underlying spacetime symmetries for the physical system of a free massless relativistic particle. The above spacetime symmetry…

High Energy Physics - Theory · Physics 2009-11-10 R. P. Malik

We investigate a three-dimensional gravitational theory on a noncommutative space which has a cosmological constant term only. We found various kinds of nontrivial solutions, by applying a similar technique which was used to seek…

High Energy Physics - Theory · Physics 2015-05-14 Tsuguhiko Asakawa , Shinpei Kobayashi

Noncommutative quantum mechanics can be considered as a first step in the construction of quantum field theory on noncommutative spaces of generic form, when the commutator between coordinates is a function of these coordinates. In this…

Mathematical Physics · Physics 2013-11-20 V. G. Kupriyanov

In this paper we present the noncommutative Bianchi Class A cosmological models coupled to barotropic perfect fluid. The commutative and noncommutative quantum solution to the Wheeler-DeWitt equation for any factor ordering, to the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Aguero , J. A. Aguilar S. , C. Ortiz , M. Sabido , J. Socorro

Scalar fields play an important role in constructing modified gravity theories. In the case of a single scalar field with timelike gradient, the corresponding Lagrangian in the unitary gauge takes the form of spatially covariant gravity…

General Relativity and Quantum Cosmology · Physics 2024-07-23 Yang Yu , Zheng Chen , Xian Gao

In this thesis, I investigate how to construct a self-consistent model of deformed general relativity using canonical methods and metric variables. The specific deformation of general covariance is predicted by some studies into loop…

General Relativity and Quantum Cosmology · Physics 2019-10-07 Rhiannon Cuttell

We construct a deformed adS-Einstein-Born-Infeld black hole from noncommutative gauge theory of gravity and determine the metric coefficients up to second order on the noncommutative parameter. We analyse the modifications on the…

High Energy Physics - Theory · Physics 2020-02-12 Román Linares , Marco Maceda , Oscar Sánchez-Santos

The present paper is devoted to the study of bouncing cosmology in $f(R,T)$ modified gravity where we presume $f(R,T) = R + 2 \lambda T$, with $R$ the Ricci scalar, $T$ the trace of energy momentum tensor and $\lambda$ the model parameter.…

General Relativity and Quantum Cosmology · Physics 2020-04-07 Snehasish Bhattacharjee , P. K. Sahoo

We study modifications of the Schwarzschild solution within the noncommutative gauge theory of gravity. In the present analysis, the deformed solutions are obtained by solving the field equations perturbatively, up to the second order in…

High Energy Physics - Theory · Physics 2015-09-23 R. Bufalo , A. Tureanu

We explore a background-independent theory of composite gravity. The vacuum expectation value of the composite metric satisfies Einstein's equations (with corrections) as a consistency condition, and selects the vacuum spacetime. A…

General Relativity and Quantum Cosmology · Physics 2021-06-09 Austin J. Batz , Joshua Erlich , Luke Mrini

We consider a problem of the consistent deformation of physical system introducing a new features, but preserving its fundamental properties. In particular, we study how to implement the noncommutativity of space-time without violation of…

High Energy Physics - Theory · Physics 2014-09-15 V. G. Kupriyanov

We explore the consequences of time-space noncommutativity in the quantum mechanics of atoms and molecules, focusing on the Moyal plane with just time-space noncommutativity ($[\hat{x}_\mu ,\hat{x}_\nu]=i\theta_{\mu\nu}$, $\theta_{0i}\neqq…

High Energy Physics - Theory · Physics 2010-11-05 A. P. Balachandran , A. Pinzul

Noncommutative space has been found to be of use in a number of different contexts. In particular, one may use noncommutative spacetime to generate quantised gravity theories. Via an identification between the Moyal $\star$-product on…

High Energy Physics - Theory · Physics 2015-05-20 Andrew Iskauskas

Theories based on the Ricci and the trace of the energy-momentum tensor, or the short name Ricci-trace-based (RTB) theories, represent a gravitational approach based on the Ricci scalar $R$, and the trace of the energy-momentum tensor…

General Relativity and Quantum Cosmology · Physics 2024-09-24 Jonas Pinheiro da Silva , Hermano Velten

We consider the Brans-Dicke theory in non-metricity gravity, which belongs to the family of symmetric teleparallel scalar-tensor theories. Our focus lies in exploring the implications of the conformal transformation, as we derive the…

General Relativity and Quantum Cosmology · Physics 2023-10-26 Andronikos Paliathanasis
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