117 citations
- Ferdowsi University of MashhadIR10 papers
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8 papers · 1 filter
The Role of Torsion in Trans-Planckian Physics
Elham Arabahmadi, Siamak Akhshabi
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…
Gravitational Slip parameter and Gravitational Waves in Einstein-Cartan theory
Maryam Ranjbar, Siamak Akhshabi, Mohsen Shadmehri
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 whic…
Cosmological Distances And Hubble Tension In Einstein-Cartan Theory
Siamak Akhshabi, Saboura Zamani
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 distan…
Gravitational lensing by a black hole in Poincar{é} gauge theory of gravity
Saboura Sadat Zamani, Siamak Akhshabi
Using a recently found black hole solution in the framework of the Poincar{é} gauge theory of gravity, we study gravitational lensing for a system where the lens is a static spheri…
Light propagation and optical scalars in torsion theories of gravity
Siamak Akhshabi
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…
Inflation by spin and torsion in Poincare gauge theory of gravity
Siamak Akhshabi, Elham Qorani, Fazeleh Khajenabi
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 en…