Article
Physics, Multidisciplinary
S. Ghaffari, Giuseppe Gaetano Luciano, S. Capozziello
Summary: We constructed a holographic model for dark energy in the Brans-Dicke cosmology by incorporating the Barrow entropy. The Hubble horizon was used as the IR cutoff to explore the cosmological consequences. We found that both the non-interacting and interacting cases can explain the current accelerated expansion of the universe, unlike the standard holographic dark energy model. Stability analysis showed that the non-interacting model was unstable, while the sign-changeable interacting model was stable only for certain parameter values. The linear interacting model always predicted a stable universe. The consistency of the model with cosmological observations was discussed.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Physics, Particles & Fields
Anil Kumar Yadav
Summary: This paper investigates the power law variation of the Brans-Dicke scalar field with the scale factor in a Universe filled with dark matter and Tsallis type holographic dark energy. It is found that specific choices of the free parameters lead to consistent results, while the energy conservation law for Tsallis holographic dark energy in Brans-Dicke gravity is not valid.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Particles & Fields
Pinki, Pankaj Kumar, Aroonkumar Beesham
Summary: In this paper, the concept of holographic dark energy in the framework of Brans-Dicke theory is reconsidered. The authors investigate the deceleration parameter, Hubble parameter, Brans-Dicke scalar field, and phase transition of the universe. Statefinder diagnostics is applied to compare the model with existing ones.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
S. Ghaffari
Summary: By utilizing the holographic hypothesis and Kaniadakis generalized entropy, a Kaniadakis holographic dark energy (DE) model is constructed in the Brans-Dicke framework. The cosmological parameters of this model, with the Hubble horizon as the infrared cutoff, are derived to investigate its cosmological consequences. The study demonstrates that, even in the absence of interaction between the dark sectors of the universe, the Kaniadakis holographic DE model with the Hubble radius as the infrared cutoff can account for the present accelerated expansion phase.
MODERN PHYSICS LETTERS A
(2022)
Article
Physics, Particles & Fields
Onder Dunya, Levent Akant, Metin Arik, Yelda Kardas, Selale Sahin, Tarik Tok
Summary: A field theoretical approach was investigated to extend the Jordan-Brans-Dicke (JBD) theory on a cosmological background, revealing a coupled Lagrangian density for the JBD field and the scale factor. The study demonstrated that particle masses remain constant while the universe is expanding.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Bardia H. Fahim, Valerio Faraoni, Andrea Giusti
Summary: A new one-parameter family of solutions to the vacuum Brans-Dicke field equations is reported in this study, which are spherically symmetric, inhomogeneous, and time-dependent. These solutions are conformal to the Roberts scalar field geometries of Einstein gravity and contain a naked central singularity. By using this new solution as a seed, another two-parameter family of solutions can be generated through a known symmetry of vacuum Brans-Dicke gravity.
Article
Physics, Nuclear
Mahasweta Biswas, Ujjal Debnath
Summary: In this study, we investigate the stability of generalized ghost dark energy and new holographic dark energy in the framework of Chameleon Brans-Dicke gravity. The adiabatic squared sound speed is crucial for analyzing the stability of these models. We find that these models are stable with suitable parameter choices in a nonflat FLRW universe.
INTERNATIONAL JOURNAL OF MODERN PHYSICS A
(2022)
Article
Astronomy & Astrophysics
Kunio Kaneta, Kin-ya Oda, Motohiko Yoshimura
Summary: This paper presents a cosmological analysis of extended Jordan-Brans-Dicke (eJBD) gravity in the Einstein metric frame. It is the first systematic investigation of how to introduce the lagrangian of standard particle physics in the eJBD framework consistently. The study is significant for understanding the time evolution of eJBD gravity and its compatibility with observational and laboratory bounds.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Physics, Particles & Fields
Hatice Ozer, Ozgur Delice
Summary: The study investigates weak field gravitational wave solutions in Brans-Dicke theory with a cosmological constant, revealing massless scalar waves and their effects on free particles and polarization properties. The analysis also includes the role of the cosmological constant in these phenomena and discusses the energy flux of these waves, leading to an extension of the Cosmic no Hair Conjecture to BD theory with a cosmological constant.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Multidisciplinary
Sania, Nadeem Azhar, Shamaila Rani, Abdul Jawad
Summary: In this paper, we investigate the cosmological and thermodynamic aspects of the Brans-Dicke theory of gravity for a spatially flat FRW universe. By considering the interaction between Kaniadakis holographic dark energy and matter, we study different aspects of cosmic evolution and explore the state and parameters of the universe. The results show that the model is consistent with the current accelerating expansion of the universe and the suggested range of Planck data, and also satisfies the generalized second law of thermodynamics.
Article
Astronomy & Astrophysics
Simran Kaur, C. P. Singh
Summary: This study discusses the adiabatic matter creation in a spatially flat, homogeneous, and isotropic universe within the context of holographic dark energy (HDE) in Brans-Dicke theory. The HDE model with matter creation is shown to unify early and late-time acceleration, with best fit values obtained through observational data and thermodynamic analysis. Comparisons with ΛCDM model and discussion about model viability are also explored.
PHYSICS OF THE DARK UNIVERSE
(2021)
Article
Astronomy & Astrophysics
Alexandre M. R. Almeida, Julio C. Fabris, Mahamadou Hamani Daouda, Richard Kerner, Hermano Velten, Willian S. Hipolito-Ricaldi
Summary: This paper introduces a unimodular version of the Brans-Dicke theory with a constrained Lagrangian formulation, resulting in traceless field equations. The vacuum solutions in the cosmological background reproduce the solutions of the usual Brans-Dicke theory with an additional cosmological constant term. A perturbative analysis of the scalar modes reveals both stable and unstable configurations, contrasting with the Brans-Dicke case where only stable configurations occur. However, the tensorial modes remain unchanged in this theory compared to the traditional Brans-Dicke theory.
Article
Astronomy & Astrophysics
J. Sadeghi, S. Noori Gashti, T. Azizi
Summary: In this paper, two different dynamic structures of holographic dark energy, Tsallis and Kaniadakis, are studied within the framework of Brans-Dicke cosmology. The complex form of the quintessence model is considered, and various cosmological parameters are calculated and discussed. The effects of the fractional energy density and the two parts of the quintessence field are examined, and relationships between these parameters are established.
MODERN PHYSICS LETTERS A
(2023)
Article
Astronomy & Astrophysics
Gabriele S. J. Gionti
Summary: This study explores the Jordan and Einstein frames in the context of Hamiltonian formalism, analyzing the Brans-Dicke theory using Dirac's constraint theory. Contrary to popular belief, the Weyl transformation between these frames is not considered a canonical transformation in the Hamiltonian formalism, highlighting quantum mechanical inequivalence. Additionally, a canonical transformation is demonstrated in the study.
Article
Physics, Particles & Fields
M. Dehghani
Summary: It has been shown that the exact solutions of the 4D Brans-Dicke-Maxwell (BDM) theory are Reissner-Nordstrom (RN) black holes coupled to a constant scalar field or zero. However, when the scalar potential is not constant or zero, novel black hole solutions affected by a nontrivial scalar hair are obtained. The inclusion of the scalar hair makes the asymptotic behavior of the solutions non-flat and non-AdS, and the theory allows for the occurrence of multi-horizon black holes due to the conformal invariance of Maxwell's electrodynamics, implying anti-evaporation quantum effect. The thermodynamic properties and stability of the BDM black holes are analyzed and found to satisfy the first law of black hole thermodynamics.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Zeinab Teimoori, Kazem Rezazadeh, Kayoomars Karami
Summary: This study investigates the formation of primordial black holes (PBHs) as a possible candidate for dark matter, utilizing a gravitationally enhanced friction mechanism. By considering a nonminimal derivative coupling between the scalar field and gravity, three parameter sets were identified that resulted in ultra slow-roll inflation, leading to the formation of PBHs. The model also predicts the presence of secondary gravitational waves (GWs) at frequencies within the sensitivity region of certain GW detectors, allowing for observational compatibility assessment.
ASTROPHYSICAL JOURNAL
(2021)
Article
Physics, Particles & Fields
Seyed Hossein Hendi, Somayeh Hajkhalili, Mubasher Jamil, Mehrab Momennia
Summary: This paper investigates the thermodynamics and phase transitions of a four-dimensional rotating Kaluza-Klein black hole solution in the presence of Maxwell electrodynamics. The stability of the black hole is checked in the canonical ensemble by analyzing the behavior of the heat capacity. Additionally, the study explores massive scalar perturbations coupled to the background geometry of the static Kaluza-Klein black hole and investigates quasinormal modes using the WKB approximation.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Mathematical
Kimet Jusufi, Mustapha Azreg-Ainou, Mubasher Jamil, Tao Zhu
Summary: This paper investigates the effects of the Generalized Uncertainty Principle (GUP) on the shadow and quasinormal modes (QNMs) of GUP-modified Kerr black holes. The study reveals that the GUP modification increases the curvature radius of the shadow and that it increases linearly with the GUP parameter. By using observational data and fitting techniques, the upper limits of the GUP parameter and the correction parameter in the modified black hole metric are determined.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2022)
Article
Astronomy & Astrophysics
Kimet Jusufi, Mustapha Azreg-Ainou, Mubasher Jamil, Emmanuel N. Saridakis
Summary: Using observations of the central black hole and stars, we extract constraints on Barrow entropy, finding an upper bound less strong than the Big Bang Nucleosynthesis but significantly stronger than late-time cosmological constraints.
Article
Astronomy & Astrophysics
Javlon Rayimbaev, Bushra Majeed, Mubasher Jamil, Kimet Jusufi, Anzhong Wang
Summary: In this article, we investigate the particle dynamics around a Bardeen-Kiselev black hole, including its geometrical properties, the dynamics of test particles, and the relationship with rotating Kerr black hole.
PHYSICS OF THE DARK UNIVERSE
(2022)
Article
Astronomy & Astrophysics
Kimet Jusufi, Mustapha Azreg-Ainou, Mubasher Jamil, Qiang Wu
Summary: This paper focuses on the relationship between quasinormal modes (QNMs) and a rotating black hole shadow, using the example of a quantum deformed Kerr black hole. The study shows that, in the eikonal limit, the real part of QNMs is related to the Keplerian frequency for equatorial orbits. The paper also explores the typical shadow radius, computes the corresponding modes, and investigates the thermodynamical stability of the quantum deformed Kerr black hole, as well as other astrophysical applications.
Article
Astronomy & Astrophysics
Javlon Rayimbaev, Ahmadjon Abdujabbarov, Mubasher Jamil, Wen-Biao Han, Malika Khudoyberdieva
Summary: This paper discusses the motion of various types of charged, magnetized, and neutral test particles near static and spherically symmetric electrically charged black holes in the Einstein-/Ether gravitational theory. The effects of the free parameters in the theory on particle motion in curved spacetime are analyzed, focusing on the stability of circular and radially varying orbits for different types of particles. The behavior of charged particle motion around black holes with a uniform magnetic field is investigated, and values of the parameters c13 and c14 are proposed to model astrophysical black holes based on the spin of Kerr black holes.
MODERN PHYSICS LETTERS A
(2022)
Article
Astronomy & Astrophysics
Mohammad Sadeghi, Karam Bahari, Kayoomars Karami
Summary: Observations indicate the existence of twisted magnetic flux tubes and plasma flow in the solar atmosphere. The goal of this study is to determine the damping rate of sausage modes in the presence of magnetic twist and plasma flow. By numerically solving the dispersion relation for sausage modes in a non-uniform layer with magnetic pores under the condition of slow continuity, we find that the effect of twisted magnetic field on resonance absorption is greater for low speed plasma flow than for high speed.
ASTROPHYSICAL JOURNAL
(2023)
Article
Physics, Nuclear
Farruh Atamurotov, Mubasher Jamil, Kimet Jusufi
Summary: In this study, the optical properties of a renormalization group improved Schwarzschild black hole in a plasma medium are investigated. The deflection angle of light in the weak gravity regime is computed for uniform and non-uniform plasma media, revealing the modifications caused by the plasma medium. The effects of plasma media play an important role in the optical appearance of black holes.
Article
Physics, Particles & Fields
Kimet Jusufi, Salvatore Capozziello, Sebastian Bahamonde, Mubasher Jamil
Summary: We use observational data to constrain a black hole solution of extended teleparallel gravity models based on the S2 star orbiting the Galactic Center. We construct the shadow images of the Sgr A* black hole and find that the shadow radius increases with the parameter alpha. The observables, such as the deflection angle and angular diameter, are close to the Schwarzschild case. However, the electromagnetic intensity observed in the shadow images is smaller compared to General Relativity (GR), indicating differences in the Born-Infeld f(T) gravity.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Kimet Jusufi, Saurabh Kumar, Mustapha Azreg-Ainou, Mubasher Jamil, Qiang Wu, Cosimo Bambi
Summary: In this study, we investigate the possibility of a wormhole as a candidate for the central object of Sgr A(star) and test this idea by constraining their geometry using the motion of S2 star and the reconstructed shadow images. We consider three wormhole models and find that they satisfy the flare out condition. We also explore the accretion of infalling gas model and study the accretion rate, electromagnetic radiation intensity, and shadow images.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Sanjar Shaymatov, Mubasher Jamil, Kimet Jusufi, Kazuharu Bamba
Summary: In this study, we investigate the dynamics of test particles around a magnetized Ernst black hole, taking into account its surrounding magnetic field. We find that the magnetic field has a significant impact on the radius of the innermost stable circular orbit (ISCO) and the epicyclic frequencies, especially for charged particles. By analyzing the astrophysical quasiperiodic oscillation (QPO) data of three microquasars, we determine the order of magnitude of the magnetic field.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Correction
Astronomy & Astrophysics
Cheng Liu, Tao Zhu, Qiang Wu, Kimet Jusufi, Mubasher Jamil, Mustapha Azreg-Ainou, Anzhong Wang
Article
Astronomy & Astrophysics
S. Amiri, K. Karami, Z. Ebrahimi
Summary: This paper evaluates the effects of inclination and asymmetry of solar coronal loops on kink magnetohydrodynamic oscillations. It is found that the frequencies and damping rates of the oscillations are smaller in inclined and asymmetric loops compared to uninclined loops. The ratios of mode frequency to damping rate remain unchanged approximately regardless of inclination or asymmetry, and these ratios can reliably infer the physical parameters of coronal loops and medium.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Kimet Jusufi, Mustapha Azreg-Ainou, Mubasher Jamil, Shao-Wen Wei, Qiang Wu, Anzhong Wang
Summary: This paper obtains an effective metric describing a regular and rotating magnetic black hole solution and studies various properties including BH shadow, QNMs, QPOs, and observational constraints on the EYM parameter. The study shows interesting correlations between the magnetic charge, shadow radius, and QNMs of scalar and electromagnetic fields, also distinguishing the rotating EYM black hole from the Kerr-Newman black hole.
