54 citations · 296 across the 38 of their papers we have counts for
14 papers · 1 filter
A Survey through Conformal Time
Tahereh Aeenehvand, Ahmad Shariati
We revisit conformal time in a spatially flat Friedmann--Robertson--Walker universe and use a -dimensional setting as a technically transparent pedagogical arena. Our purp…
Modified Inertia as Nonconservative Newtonian Dynamics
Ahmad Shariati, Nosratollah Jafari
Modified Newtonian dynamics by Milgrom is a paradigm for explaining the rotation curves of spiral galaxies and various other large scale structures. This paradigm includes several…
Is there a map between Galilean relativity and special relativity?
Ahmad Shariati, N. Jafari
Mandanici has provided a map which he claims to be a two way map between Galilean relativity and special relativity. We argue that this map is simply a curvilinear coordinate syste…
A Projective Interpretation of Some Doubly Special Relativity Theories
N. Jafari, A. Shariati
A class of projective actions of the orthogonal group on the projective space is being studied. It is shown that the Fock--Lorentz, and Magueijo--Smolin transformations known as Do…
MOND, dark matter, and conservation of energy
Ahmad Shariati, Nosratollah Jafari
The MOND equation could be transformed to the equivalent form , where $\Vec{F'}$ is a transformed force. Using this transformation we…
Doubly Special Relativity: A New Relativity or Not?
Nosratollah Jafari, Ahmad Shariati
Double Special Relativity theories are the relativistic theories in which the transformations between inertial observers are characterized by two observer-independent scales of the…
A tight constraint on some varying speed of light theories
Ahmad Shariati, Nosratollah Jafari
We argue that if the velocity of electromagnetic waves in vacuum, \cem, is different from the limiting velocity for massive particles, \cst, then, a proton moving with velocity $\c…
Comments on the Quantum Vacuum and the Light Acceleration
Nosratollah Jafari, Ahmad Shariati
The recent observations on the far quasars absorption lines spectra and comparison of these lines with laboratory ones provide a framework for explantation of these observations by…
Operational indistinguishably of varying speed of light theories
Nosratollah Jafari, Ahmad Shariati
The varying speed of light theories have been recently proposed to solve the standard model problems and anomalies in the ultra high energy cosmic rays. These theories try to formu…
Spin 0 and spin 1/2 quantum relativistic particles in a constant gravitational field
M. Khorrami, M. Alimohammadi, A. Shariati
The Klein-Gordon and Dirac equations in a semi-infinite lab (), in the background metric $\ds^2 = u^2(x) (-\dt^2 + \dx^2) + \dy^2 + \dz^2$, are investigated. The resulting e…
Berry phase for spin--1/2 particles moving in a spacetime with torsion
M. Alimohammadi, A. Shariati
Berry phase for a spin--1/2 particle moving in a flat spacetime with torsion is investigated in the context of the Einstein-Cartan-Dirac model. It is shown that if the torsion is d…
Equivalence principle and radiation by a uniformly accelerated charged particle
A. Shariati, M. Khorrami
We address the old question of whether or not a uniformly accelerated charged particle radiates, and consequently, if weak equivalence principle is violated by electrodynamics. We…
Quantum reflection of massless neutrinos from a torsion-induced potential
M. Alimohammadi, A. shariati
In the context of the Einstein-Cartan-Dirac model, where the torsion of the space-time couples to the axial currents of the fermions, we study the effects of this quantum-gravitati…
Neutrino oscillation in a space-time with torsion
M. alimohammadi, A. Shariati
Using the Einstein-Cartan-Dirac theory, we study the effect of torsion on neutrino oscillation. We see that torsion cannot induce neutrino oscillation, but affects it whenever osci…