108 citations · 875 across the 25 of their papers we have counts for
26 papers
Passive Identification of Unequal Phase Grid Impedances by Phase-Domain Source Cancellation
Songyang Zhang, Xun Gong, Bo Cao +1
Passive grid impedance estimators that return a single resistance--inductance pair cannot represent a grid whose phase impedances are unequal. This paper identifies a separate pair…
A Six-Parameter Teleparallel Cosmology Beyond CDM: Sign-Changing Torsional Dark Energy and Implications for
Mohamed Bedair, Mahmoud Hashim, Jackson Levi Said +1
We investigate a particular case of the extended exponential infrared f(T) teleparallel gravity, in which the geometric sector naturally produces an effective dark-energy density t…
Cosmological Viability of Exponential Infrared Gravity
Mahmoud Hashim, Eleonora Di Valentino, Jackson Levi Said +1
We investigate the cosmological viability of exponential infrared teleparallel gravity using current cosmological observations. This framework realizes late-time cosmic acce…
Revisiting Flat Rotation Curves in Chern-Simons Modified Gravity
Waleed El Hanafy, Mahmoud Hashim, G. G. L. Nashed
We revisit slow rotating black hole (BH) solutions in Chern-Simons modified gravity (CSMG) by considering perturbative solution about Schwarzschild BH. In particular, the case when…
Quadratic Rastall Gravity: from low-mass HESS J1731-347 to high-mass PSR J0952-0607 pulsars
Waleed El Hanafy
Similar to Rastall gravity we introduce matter-geometry nonminimal coupling which is proportional to the gradient of quadratic curvature invariants. Those are mimicking the conform…
Implications of the Conformal Constraint on Sound Speed on the Radius of PSR J0952-0607 within Rastall Gravity
Waleed El Hanafy, Adel Awad
It has been shown that the nonminimal coupling between geometry and matter can provide models for massive compact stars that are consistent with the conformal bound on the sound sp…
Impact of Rastall gravity on mass, radius and sound speed of the pulsar PSR J0740+6620
Waleed El Hanafy
Millisecond pulsars are perfect laboratories to test possible matter-geometry coupling and its physical implications in light of recent Neutron Star Interior Composition Explorer (…
Non-trivial class of anisotropic compact stellar model in Rastall gravity
G. G. L. Nashed, W. El Hanafy
We investigated Rastall gravity, for an anisotropic star with a static spherical symmetry, whereas the matter-geometry coupling as assumed in Rastall Theory (RT) is expected to pla…
Revisiting diagonal tetrads: New Black Hole solutions in gravity
Adel Awad, Alexey Golovnev, María-José Guzmán +1
We study various forms of diagonal tetrads that accommodate Black Hole solutions in gravity with certain symmetries. As is well-known, vacuum spherically symmetric diagonal…
Toward a concordance teleparallel Cosmology II: Linear perturbation
Mahmoud Hashim, Amr A. El-Zant, Waleed El Hanafy +1
Late time cosmic acceleration may be achieved by modifying gravity on large scales. This should also have consequences on the evolution of perturbations. We thus extend our study o…
Toward a concordance teleparallel Cosmology I: Background Dynamics
Mahmoud Hashim, Waleed El Hanafy, Alexey Golovnev +1
Assuming a spatially flat universe, we study the cosmological viability of an infrared corrected teleparallel gravity model, which accounts for late acceleration by weakening gravi…
Phase Portraits of general f(T) Cosmology
A. Awad, W. El Hanafy, G. G. L. Nashed +1
We use dynamical system methods to explore the general behaviour of cosmology. In contrast to the standard applications of dynamical analysis, we present a way to transform…
Constant-roll Inflation in Teleparallel Gravity
A. Awad, W. El Hanafy, G. G. L. Nashed +2
We investigate in detail the implications of the constant-roll condition on the inflationary era of a scalar field coupled to a teleparallel gravity. The resulting cosmologi…
Generic Phase Portrait Analysis of the Finite-time Singularities and Generalized Teleparallel Gravity
W. El Hanafy, G. G. L. Nashed
We analyze the common four types of the finite-time singularities using a generic framework of the phase portrait geometric approach. This technique requires that the Friedmann sys…
Analytic rotating black hole solutions in -dimensional gravity
G. G. L. Nashed, W. El Hanafy
A non-diagonal vielbein ansatz is applied to the -dimension field equations of gravity. An analytical vacuum solution is derived for the quadratic polynomial $f(T)=T+εT^2…
Einstein Geometrization Philosophy and Differential Identities in PAP-Geometry
M. I. Wanas, Nabil L. Youssef, W. El Hanafy +1
The importance of Einstein's geometrization philosophy, as an alternative to the least action principle, in constructing general relativity (GR), is illuminated. The role of differ…
Bounce inflation in Cosmology: A unified inflaton-quintessence field
Kazuharu Bamba, G. G. L. Nashed, W. El Hanafy +1
We investigate a bounce inflation model with a graceful exit into the Friedmann-Robertson-Walker (FRW) decelerated Universe within gravity framework, where is the torsio…
Cosmological behaviors of the cubic gravity in early and late universe
G. G. L. Nashed, W. El Hanafy
A cubic correction of gravity, where is the teleparallel scalar torsion, is considered to describe gravity in spatially flat Friedmann-Robertson-Walker model. A scale fa…
The Hidden Flat Like Universe II: Quasi inverse power law inflation by gravity
W. El Hanafy, G. G. L. Nashed
In a recent work, a particular class of gravity, where is the teleparallel torsion scalar, has been derived. This class has been identified by flat-like universe (FLU) a…
Exact Teleparallel Gravity of Binary Black Holes
W. El Hanafy, G. G. L. Nashed
An exact solution of two singularities in the teleparallel equivalent to general relativity theory has been obtained. A holographic visualization of the binary black holes (BBHs) s…
Graceful Exit Inflation in Gravity
G. G. L. Nashed, W. El Hanafy, Sh. Kh. Ibrahim
We apply a quadratic teleparallel torsion scalar of the field equations to the spatially flat Friedmann-Robertson-Walker (FRW) model. We assume two perfect fluid co…
Reconstruction of -gravity in the absence of matter
W. El Hanafy, G. L. Nashed
We derive an exact gravity in the absence of ordinary matter in Friedmann-Robertson-Walker (FRW) universe, where is the teleparallel torsion scalar. We show that vanishi…
The Hidden Flat Like Universe: Starobinsky-like inflation induced by f(T) gravity
W. El Hanafy, G. G. L. Nashed
We study a single fluid component in a flat like universe (FLU) governed by gravity theories, where is the teleparallel torsion scalar. The FLU model, regardless the val…
Pure Geometric Field Theory: Description of Gravity and Material Distribution
M. I. Wanas, Nabil L. Youssef, W. El Hanafy
A field theory is constructed in the context of parameterized absolute parallelism geometry. The theory is shown to be a pure gravity one. It is capable of describing the gravitati…