362 citations · 8.3k across the 216 of their papers we have counts for
26 papers · 1 filter
Constraints on Rényi Entropy through Primordial Big-Bang Nucleosynthesis and Baryogenesis
Ahmad Sheykhi, Ava Shahbazi Sooraki
The Rényi entropy, a one-parameter generalization of Boltzmann-Gibbs entropy, offers a promising framework for probing quantum gravitational effects in cosmology. By modifying the…
Three dimensional charged black holes in Gauss-Bonnet gravity
Kimet Jusufi, Mubasher Jamil, Ahmad Sheykhi
By using the zero-point length effect, we construct a new class of charged black hole solutions in the framework of three dimensional Gauss-Bonnet (GB) gravity with Maxwell electro…
New black hole solutions in three-dimensional gravity
G. G. L. Nashed, A. Sheykhi
We construct two new classes of analytical solutions in three-dimensional spacetime and in the framework of gravity. The first class represents a non-rotating black hole (BH…
New explanation for accelerated expansion and flat galactic rotation curves
Ahmad Sheykhi
Employing the non-additive Tsallis entropy, , for the large-scale gravitational systems, we disclose that in the cosmological scales both Friedmann equation and the equa…
Alternative approach to the critical behavior and microscopic structure of the power-Maxwell black holes
Ahmad Sheykhi, Mohammad Arab, Zeinab Dayyani +1
Employing a new approach toward thermodynamic phase space, we investigate the phase transition, critical behavior and microscopic structure of higher dimensional black holes in an…
Tsallis Agegraphic Dark Energy Model
M. Abdollahi Zadeh, A. Sheykhi, H. Moradpour
Using the nonextensive Tsallis entropy and the holographic hypothesis, we propose a new dark energy (DE) model with time scale as infrared (IR) cutoff. Considering the age of the U…
Implications of the Generalized Entropy Formalisms on the Newtonian Gravity and Dynamics
H. Moradpour, A. Sheykhi, C. Corda +1
Employing the Verlinde's hypothesis, and considering two well-known generalized entropy formalisms, two modifications to the Newtonian gravity are derived. In addition, it has been…
A note on holographic dark energy with varying term
A. Sheykhi, S. Ghaffari, N. Roshanshah
We reconsider the holographic dark energy (HDE) model with a slowly time varying parameter in the energy density, namely , where is the IR cuto…
Rotating black strings in -Maxwell theory
S. Salarpour, A. Sheykhi, Y. Bahrampour
In general, the field equations of theory coupled to a matter field are very complicated and hence it is not easy to find exact analytical solutions. However, if one conside…
Thermodynamics of Fractal Universe
Ahmad Sheykhi, Zeinab Teimoori, Bin Wang
We investigate the thermodynamical properties of the apparent horizon in a fractal universe. We find that one can always rewrite the Friedmann equation of the fractal universe in t…
Sounds of instability from generalized QCD ghost dark energy
Esmaeil Ebrahimi, Ahmad Sheykhi
We investigate about the stability of generalized QCD ghost dark energy model against perturbations in the FRW background. For this purpose, we use the squared sound speed …
Einstein Equations and MOND Theory from Debye Entropic Gravity
A. Sheykhi, K. Rezazadeh Sarab
Verlinde's proposal on the entropic origin of gravity is based strongly on the assumption that the equipartition law of energy holds on the holographic screen induced by the mass d…
Modified Friedmann Equations From Debye Entropic Gravity
A. Sheykhi, Z. Teimoori
A remarkable new idea on the origin of gravity was recently proposed by Verlinde who claimed that the laws of gravitation are no longer fundamental, but rather emerge naturally as…
Lovelock gravity from entropic force
A. Sheykhi, H. Moradpour, N. Riazi
In this paper, we first generalize the formulation of entropic gravity to (n+1)-dimensional spacetime. Then, we propose an entropic origin for Gauss-Bonnet gravity and more general…
Holographic Scalar Fields Models of Dark Energy
Ahmad Sheykhi
Many theoretical attempts toward reconstructing the potential and dynamics of the scalar fields have been done in the literature by establishing a connection between holographic/ag…
Power Law Entropy Corrected New-Agegraphic Dark Energy in Hořava-Lifshitz Cosmology
K. Karami, A. Sheykhi, Mubasher Jamil +3
We investigate the new agegraphic dark energy (NADE) model with power-law corrected entropy in the framework of Hořava-Lifshitz cosmology. For a non-flat universe containing the in…
Quintessence Ghost Dark Energy Model
Ahamd Sheykhi, Ali Bagheri
A so called "ghost dark energy" was recently proposed to explain the present acceleration of the universe expansion. The energy density of ghost dark energy, which originates from…
Viscous dark energy and generalized second law of thermodynamics
M. R. Setare, A. Sheykhi
We examine the validity of the generalized second law of thermodynamics in a non-flat universe in the presence of viscous dark energy. At first we assume that the universe filled o…
Thermodynamics of viscous dark energy in an RSII braneworld
M. R. Setare, A. Sheykhi
We show that for an RSII braneworld filled with interacting viscous dark energy and dark matter, one can always rewrite the Friedmann equation in the form of the first law of therm…
Power-Law Entropy Corrected Holographic Dark Energy Model
Ahmad Sheykhi, Mubasher Jamil
Among various scenarios to explain the acceleration of the universe expansion, the holographic dark energy (HDE) model has got a lot of enthusiasm recently. In the derivation of ho…
Holographic dark energy in Brans-Dicke cosmology with Granda-Oliveros cut-off
Mubasher Jamil, Kayoomars Karami, Ahmad Sheykhi +2
Motivated by the recent works of one of us [1,2] we study the holographic dark energy in Brans-Dicke gravity with the Granda-Oliveros cut-off proposed recently in literature. We fi…
Holographic dark energy in Brans-Dicke theory with log correction
Ahmad Sheykhi, Kayoomars Karami, Mubasher Jamil +2
In the derivation of holographic dark energy density, the area law of the black hole entropy plays a crucial role. However, the entropy-area relation can be modified from the inclu…
Restoring New Agegraphic Dark Energy in RS II Braneworld
Mubasher Jamil, Kayoomars Karami, Ahmad Sheykhi
Motivated by recent works [1,2], we investigate new agegraphic model of dark energy in the framework of RS II braneworld. We also include the case of variable gravitational constan…
Interacting entropy-corrected agegraphic-tachyon dark energy
Mubasher Jamil, Ahmad Sheykhi
Motivated by recent work of one of us [1], we generalize this work to agegraphic tachyon models of dark energy with entropy correction terms arising from loop quantum gravity. We e…