Zobrazeno 1 - 10
of 152
pro vyhledávání: '"Shahidi, Shahab"'
We consider a mimetic type extension of the Weyl geometric gravity theory, by assuming that the metric of the space-time manifold can be parameterized in terms of a scalar field, called the mimetic field. The action of the model is obtained by starti
Externí odkaz:
http://arxiv.org/abs/2410.22787
In a recent paper (Lacombe, Mukohyama, and Seitz, JCAP {\bf 2024}, 05, 064 (2024)), the authors provided an in-depth analysis of a class of modified gravity theories, generally called $f(R,{\rm Matter})$ theories, which assume the existence of a non-
Externí odkaz:
http://arxiv.org/abs/2408.13594
Autor:
Harko, Tiberiu, Shahidi, Shahab
Publikováno v:
Eur. Phys. J. C 84, 509 (2024)
We consider cosmological implications of the Weyl geometric gravity theory. The basic action of the model is obtained from the simplest conformally invariant gravitational action, constructed, in Weyl geometry, from the square of the Weyl scalar, the
Externí odkaz:
http://arxiv.org/abs/2405.04129
In a recent Comment on the paper "Dark matter as a Weyl geometric effect", by Burikham et al., Phys. Rev. D 107, 064008 (2023), posted on arxiv. org as eprint arXiv:2306.11926, it was claimed that the exact solution found in the above mentioned paper
Externí odkaz:
http://arxiv.org/abs/2310.13423
Publikováno v:
Phys. Rev. D 107 (2023) 064008
We investigate the possibility that the observed behavior of test particles outside galaxies, which is usually explained by assuming the existence of dark matter, is the result of the dynamical evolution of particles in a Weyl type geometry, and its
Externí odkaz:
http://arxiv.org/abs/2302.08289
Publikováno v:
Phys. Dark Univ. 44 (2024) 101448
The first order variation of the matter energy-momentum tensor $T_{\mu \nu}$ with respect to the metric tensor $g^{\alpha \beta}$ plays an important role in modified gravity theories with geometry-matter coupling, and in particular in the $f(R,T)$ mo
Externí odkaz:
http://arxiv.org/abs/2301.12133
Publikováno v:
Eur. Phys. J. C 82, 1171 (2022)
We consider numerical black hole solutions in the Weyl conformal geometry, and its associated conformally invariant Weyl quadratic gravity. In this model Einstein gravity (with a positive cosmological constant) is recovered in the spontaneously broke
Externí odkaz:
http://arxiv.org/abs/2212.05542
Autor:
Harko, Tiberiu, Shahidi, Shahab
Publikováno v:
Eur. Phys. J. C 82, 1003 (2022)
We investigate the field equations of the conformally invariant models of gravity with curvature-matter coupling, constructed in Weyl geometry, by using the Palatini formalism. We consider the case in which the Lagrangian is given by the sum of the s
Externí odkaz:
http://arxiv.org/abs/2210.03631
Autor:
Harko, Tiberiu, Shahidi, Shahab
We investigate the coupling of matter to geometry in conformal quadratic Weyl gravity, by assuming a coupling term of the form $L_m\tilde{R}^2$, where $L_m$ is the ordinary matter Lagrangian, and $\tilde{R}$ is the Weyl scalar. The coupling explicitl
Externí odkaz:
http://arxiv.org/abs/2202.06349
Publikováno v:
Phys. Dark Univ. 34, 100886 (2021)
We consider an extension of standard General Relativity in which the Hilbert-Einstein action is replaced by an arbitrary function of the Ricci scalar, nonmetricity, torsion, and the trace of the matter energy-momentum tensor. By construction, the act
Externí odkaz:
http://arxiv.org/abs/2110.00358