Zobrazeno 1 - 10
of 56
pro vyhledávání: '"Akhshabi, Siamak"'
Autor:
Arabahmadi, Elham, Akhshabi, Siamak
The torsion of spacetime, if exists, plays an important role at the very early universe when the spin density of particles was very high. It is generally believed that in extremely high energies of the early universe a new physics called trans-Planck
Externí odkaz:
http://arxiv.org/abs/2404.03141
Publikováno v:
Eur. Phys. J. C 84, 316 (2024)
We study the evolution of scalar and tensor cosmological perturbations in the framework of the Einstein-Cartan theory of gravity. The value of the gravitational slip parameter which is defined as the ratio of the two scalar potentials in the Newtonia
Externí odkaz:
http://arxiv.org/abs/2401.02129
Autor:
Akhshabi, Siamak, Zamani, Saboura
Publikováno v:
Gen Relativ Gravit 55, 102 (2023)
We analyze the measurement of cosmological distances in the presence of torsion in both Einstein-Cartan and Poincare gauge theory of gravity. Using the modified cosmological distance measurements, we use the observed time delays in gravitational lens
Externí odkaz:
http://arxiv.org/abs/2305.00415
Using a recently found black hole solution in the framework of the Poincar{\'e} gauge theory of gravity, we study gravitational lensing for a system where the lens is a static spherically symmetric black hole. By analyzing the equations of motion for
Externí odkaz:
http://arxiv.org/abs/2104.10016
Autor:
Akhshabi, Siamak
Publikováno v:
Modern Physics Letters A 2 Vol. 34 (2019) 1950029
We investigate the propagation of light rays and evolution of optical scalars in gauge theories of gravity where torsion is present. Recently the modified Raychaudhuri equation in the presence of torsion has been derived. We use this result to derive
Externí odkaz:
http://arxiv.org/abs/1805.07534
Publikováno v:
EPL, 119 (2017) 29002
In Poincare gauge theory of gravity, in addition to mass-energy content, spin is also a source for gravitational interactions. Although the effects of spin are negligible at low energies, they can play a crucial role at very early universe when the s
Externí odkaz:
http://arxiv.org/abs/1705.04931
Autor:
Nozari, Kourosh, Akhshabi, Siamak
Publikováno v:
Phys.Lett.B700:91-96,2011
Recently Verlinde proposed that gravity can be described as an emergent phenomena arising from changes in the information associated with the positions of material bodies. By using noncommutative geometry as a way to describe the microscopic, microst
Externí odkaz:
http://arxiv.org/abs/1104.4849
Autor:
Nozari, Kourosh, Akhshabi, Siamak
Publikováno v:
Research in Astronomy and Astrophys, 12 (2012) 625-635
Following our previous work in noncommutative braneworld inflation (arXiv:0911.4418), in this paper we use the smeared, coherent state picture of noncommutativity to study evolution of perturbations in a noncommutative braneworld scenario. We show th
Externí odkaz:
http://arxiv.org/abs/1004.5007
Autor:
Nozari, Kourosh, Akhshabi, Siamak
Publikováno v:
Phys.Lett.B683:186-190,2010
Recently a new approach to inflation proposal has been constructed via the smeared coherent state picture of spacetime noncommutativity. Here we generalize this viewpoint to a Randall-Sundrum II braneworld scenario. This model realizes an inflationar
Externí odkaz:
http://arxiv.org/abs/0911.4418
Autor:
Nozari, Kourosh, Akhshabi, Siamak
Publikováno v:
Int.J.Mod.Phys.D19:513-521,2010
We investigate the effects of the generalized uncertainty principle on the inflationary dynamics of the early universe in both standard and braneworld viewpoint. We choose the Randall-Sundrum II model as our underlying braneworld scenario. We find th
Externí odkaz:
http://arxiv.org/abs/0910.2808