326 citations · 958 across the 29 of their papers we have counts for
29 papers
Bose-Einstein Condensate dark matter with logarithmic nonlinearity
Zahra Haghani, Tiberiu Harko
If dark matter is composed of massive bosons, a Bose-Einstein Condensation process must have occurred during the cosmological evolution. Therefore, galactic dark matter may be in a…
Compact stellar structures in Weyl geometric gravity
Zahra Haghani, Tiberiu Harko
We consider the structure and physical properties of specific classes of neutron, quark, and Bose-Einstein Condensate stars in the conformally invariant Weyl geometric gravity theo…
The first variation of the matter energy-momentum tensor with respect to the metric, and its implications on modified gravity theories
Zahra Haghani, Tiberiu Harko, Shahab Shahidi
The first order variation of the matter energy-momentum tensor with respect to the metric tensor plays an important role in modified gravity theories with geometr…
Compact stars in the Einstein dark energy model
Zahra Haghani, Tiberiu Harko
We investigate the properties of high density compact objects in a vector type theory, inspired by Einstein's 1919 theory of elementary particles, in which Einstein assumed that el…
Generalizing the coupling between geometry and matter: gravity
Zahra Haghani, Tiberiu Harko
We generalize and unify the and type gravity models by assuming that the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar , of…
Matter perturbations in Einstein dark energy model
Zahra Haghani
We consider the growth rate of matter perturbations in the Einstein dark energy theory. The theory consists of the Einstien-Hilbert Lagrangian plus the trace of the energy momentum…
Static spherically symmetric three-form stars
Bruno J. Barros, Zahra Haghani, Tiberiu Harko +1
We consider interior static and spherically symmetric solutions in a gravity theory that extends the standard Hilbert-Einstein action with a Lagrangian constructed from a three-for…
Growth of matter density perturbations in 4D Einstein-Gauss-Bonnet gravity
Zahra Haghani
Recently, a novel Einstein-Gauss-Bonnet gravity in four dimensions has been introduced [Phys. Rev. Lett. 124 (2020) 081301]. We will investigate cosmological consequences of this m…
Cosmology in theories with derivative matter coupling
Zahra Haghani, Shahab Shahidi
A new class of modified gravity theories with a healthy higher order derivative terms of a function of the matter Lagrangian is considered. Generally the energy momentum t…
Cosmology of the non-local Proca theory
Zahra Haghani
In this paper, we will consider cosmological implications of the Maxwell theory coupled to a non-local -symmetric term. It is well-known that the theory in flat space time, r…
Cosmic acceleration via derivative matter couplings
Zahra Haghani, Shahab Shahidi
A gravitational theory with derivative matter coupling is proposed which adopt de Sitter expansion at late times with ordinary baryonic matter. Matter components are conserved sepa…
Modified gravity one-loop partition function
Shahab Shahidi, Farid Charmchi, Zahra Haghani +1
The one-loop partition function of the gravity theory is obtained around AdS background. After suitable choice of the gauge condition and computation of the…
The Einstein dark energy model
Zahra Haghani, Tiberiu Harko, Shahab Shahidi
In 1919 Einstein tried to solve the problem of the structure of matter by assuming that the elementary particles are held together solely by gravitational forces. In addition, Eins…
The Maxwell-Chern-Simons gravity and its cosmological implications
Zahra Haghani, Tiberiu Harko, Shahab Shahidi
We consider the cosmological implications of a gravitational theory containing two vector fields coupled minimally to gravity as well as a generalized Chern-Simons term that couple…
Quantum corrections to the generalized Proca theory via a matter field
André Amado, Zahra Haghani, Azadeh Mohammadi +1
We study the quantum corrections to the generalized Proca theory via matter loops. We consider two types of interactions, linear and nonlinear in the vector field. Calculating the…
Vector dark energy models with quadratic terms in the Maxwell tensor derivatives
Zahra Haghani, Tiberiu Harko, Hamid Reza Sepangi +1
We consider a vector-tensor gravitational model with terms quadratic in the Maxwell tensor derivatives, called the Bopp-Podolsky term. The gravitational field equations of the mode…
One-loop corrections to vector Galileon theory
Farid Charmchi, Zahra Haghani, Shahab Shahidi +1
The effective action of the recently proposed vector Galileon theory is considered. Using the background field method, we obtain the one-loop correction to the propagator of the Pr…
Energy conditions in mimetic- gravity
Zahra Haghani, Maryam Shiravand, Shahab Shahidi
The energy conditions of mimetic- gravity theory is analyzed. We will obtain the parameter space of the theory in some special forms of in which the self-acceleration…
Cosmology of a Lorentz violating Galileon theory
Zahra Haghani, Tiberiu Harko, Hamid Reza Sepangi +1
We modify the scalar Einstein-aether theory by breaking the Lorentz invariance of a gravitational theory coupled to a Galileon type scalar field. This is done by introducing a Lagr…
The Weyl-Cartan Gauss-Bonnet gravity
Zahra Haghani, Nima Khosravi, Shahab Shahidi
In this paper, we consider the generalized Gauss-Bonnet action in -dimensional Weyl-Cartan space-time. In this space-time, the presence of torsion tensor and Weyl vector implies…
Matter may matter
Zahra Haghani, Tiberiu Harko, Hamid Reza Sepangi +1
We propose a gravitational theory in which the effective Lagrangian of the gravitational field is given by an arbitrary function of the Ricci scalar, the trace of the matter energy…
The scalar Einstein-aether theory
Zahra Haghani, Tiberiu Harko, Hamid Reza Sepangi +1
We consider an Einstein-aether type Lorentz-violating theory of gravity in which the aether vector field is represented as the gradient of a scalar field , $V_{μ}=\nabla…
Weyl-Cartan-Weitzenböck gravity through Lagrange multiplier
Zahra Haghani, Tiberiu Harko, Hamid Reza Sepangi +1
We consider an extension of the Weyl-Cartan-Weitzenböck (WCW) and teleparallel gravity, in which the Weitzenböck condition of the exact cancellation of curvature and torsion in a W…
Further matters in space-time geometry: gravity
Zahra Haghani, Tiberiu Harko, Francisco S. N. Lobo +2
We consider a gravitational model in which matter is non-minimally coupled to geometry, with the effective Lagrangian of the gravitational field being given by an arbitrary functio…