Article
Physics, Particles & Fields
Swagat S. Mishra, Varun Sahni
Summary: Non-canonical scalar fields with specific Lagrangian properties have the capability to exhibit dark matter-like behavior on small scales. By manipulating the potential term, the kinetic term can be utilized as dark matter while the potential term plays the role of dark energy later on. Simple potentials like V = V-0 coth(2) phi and Starobinsky-type potentials can unify dark matter and dark energy, and cascading dark energy models are also effective in this unification.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Alvaro de la Cruz Dombriz, Francisco Jose Maldonado Torralba, David F. Mota
Summary: The stable pseudo-scalar degree of freedom in the quadratic Poincare Gauge theory of gravity is identified as a suitable candidate for dark matter. The study determines the parameter space in the theory that can explain all predicted cold dark matter phenomena and constrains these parameters with astrophysical observations.
Article
Physics, Multidisciplinary
Yu-Dai Tsai, Robert McGehee, Hitoshi Murayama
Summary: This paper presents new models based on QCD-like dark sectors to solve small-scale structure problems. By drawing analogies to the meson spectra in standard model QCD, the models introduce resonant self-interacting dark matter and discuss experimental probes for both setups. The paper also comments on the resonant self-interactions already built into SIMP and ELDER mechanisms.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Jhonny A. Agudelo Ruiz
Summary: In this work, scalar field actions minimally and non-minimally coupled to gravity are analytically constructed, showing their equivalence to RRG in producing the same cosmological solutions. Additionally, the potential of combining a scalar field model for WDM with dynamical dark energy in the form of a running cosmological constant is also explored.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Astronomy & Astrophysics
Ahmad Mehrabi, Mehdi Rezaei
Summary: The study found that the results of the cosmographic approach are not precise enough compared to other methods, especially showing significant biases at higher redshifts. Due to providing biased results, the cosmographic approach is not the best method for reconstructing cosmographic functions.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Hao Wang, Yun-Song Piao
Summary: This study finds that considering the coupling between a fraction of dark matter and EDE can help alleviate the cosmic expansion tension.
Article
Physics, Particles & Fields
Rosemin John, N. Sarath, Titus K. Mathew
Summary: The phenomenologically emergent dark energy (PEDE) model is a varying dark energy model proposed by Li and Shafieloo (Astrophys J 883(1):L3, 2019) with no extra degrees of freedom to alleviate the Hubble tension. The statistical consistency of the model has been discussed by many authors. The model's Hubble and deceleration parameters display unusual behaviour in the future, and it also follows a distinct evolution in the statefinder plane.
EUROPEAN PHYSICAL JOURNAL C
(2023)
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
Shahnawaz A. Ruchika, Shahnawaz A. Adil, Koushik Dutta, Ankan Mukherjee, Anjan A. Sen
Summary: This work discusses a dark energy model with an oscillating scalar field potential and a cosmological constant. The oscillating part of the potential represents the contribution of a light axion field in the dark energy, originating from the String-Axiverse scenario. The model has been compared with recent cosmological observations, showing that a sub-Planckian value for the axion field decay constant is consistent with the observed data. Additionally, based on the considered observational data, the axion model is preferred over the ΛCDM model in terms of AIC, BIC information criteria, and Bayesian evidence. The oscillating behavior in the scalar field evolution and dark energy equation of state can be observed in the allowed parameter space. It is also found that cluster number counts in this axion model are suppressed compared to the ΛCDM model, with the suppression being enhanced for sub-Planckian values of the axion decay constant.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Physics, Particles & Fields
Dan Wang, M. Koussour, Adnan Malik, N. Myrzakulov, G. Mustafa
Summary: In this study, a logarithmic parametrization form of energy density for scalar field dark energy is proposed within the framework of the standard theory of gravity, which allows for a necessary transition from decelerated to accelerated behavior of the Universe. The model is constrained by observational data, including cosmic chronometers datasets, baryonic acoustic oscillation datasets, and supernovae datasets, with two parameters alpha and ss. The combined analysis of these datasets confirms a transition redshift of z(tr) = 0.79(-0.02)(+0.02), consistent with recent observations. The study also provides constraints on the matter parameter density value and the present value of the Hubble parameter.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Keshav Ram Mishra, Shibesh Kumar Jas Pacif, Rajesh Kumar, Kazuharu Bamba
Summary: In this paper, an interacting dark energy model is studied by assuming gravitational interaction between matter fields and dark energy in a spatially homogeneous and isotropic Friedmann-Robertson-Walker space-time. The cosmic evolution is examined in the framework of an interacting scenario using a suitable ansatz for the scale factor parametrization of the Hubble parameter. The evolution of cosmological parameters, including deceleration parameter, energy density, pressure, and equation of state, is discussed in detail. Cosmological tests and analysis are performed to support the obtained interacting model. Additionally, the potential of the scalar field is reconstructed and the refined swampland conjecture is refuted using the equation of state and relationships between energy density, pressure, scalar field, and potential.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
Emil Brinch Holm, Thomas Tram, Steen Hannestad
Summary: Decaying dark matter models can impact the predicted value of the Hubble constant and bridge the discrepancies between CMB inferences and local measurements. In this study, a reevaluation of the warm dark matter decaying model is performed, including the mass of the decaying species, and its ability to alleviate tensions in Hubble and sigma(8) is assessed. The model shows mild improvements but further research is required to fully evaluate its effectiveness.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Matteo Lucca
Summary: The study examines a dynamic fluid model of dark energy that shows promising results in addressing the S-8 tension without significantly impacting other tensions or fit to the data sets.
PHYSICS OF THE DARK UNIVERSE
(2021)
Article
Astronomy & Astrophysics
Paul H. Frampton
Summary: We discuss a model where dark energy is replaced by electrically-charged extremely-massive dark matter. The cosmological constant is of the same order as the mean matter density, consistent with observations, and is obtained classically without fine-tuning.
MODERN PHYSICS LETTERS A
(2023)
Article
Astronomy & Astrophysics
Raja Solanki, Simran Arora, Pradyumn Kumar Sahoo, Pedro H. R. S. Moraes
Summary: The standard formulation of General Relativity Theory fails to explain the observed late-time cosmic acceleration, while modifying Einstein's spacetime geometry in f(Q) gravity theory can effectively describe the acceleration and predict the transition from deceleration to acceleration. By constraining the model with observational data, the f(Q) cosmological model is found to be capable of accurately describing the universe's expansion and the behavior of cosmic fluid, and passes various tests of viability and distinguishability among dark energy models.
Article
Physics, Nuclear
Sen Yang, Cheng Liu, Tao Zhu, Li Zhao, Qiang Wu, Ke Yang, Mubasher Jamil
Summary: This study investigates the spherical accretion flow onto general parametrized spherically symmetric black hole spacetimes, analyzing the accretion process for various perfect fluids. The influences of additional parameters beyond the Schwarzschild black hole on flow behavior are studied in detail, as well as the accretion of the ideal photon gas and its correspondence with the photon sphere for general parameterized spherically symmetric black holes. Possible extensions of the analysis are also discussed.
Article
Physics, Particles & Fields
Javlon Rayimbaev, Ahmadjon Abdujabbarov, Mubasher Jamil, Wen-Biao Han
Summary: This study investigates the effects of Einstein-(Ether gravity on magnetized particles orbiting a black hole immersed in a magnetic field, exploring the impact of free parameters on particle trajectories, innermost stable circular orbits, and collision energy. The study also compares these effects with those of rotating Kerr black holes, finding similar behavior for certain values. Additionally, the cases where a static /Ether black hole can be described as a Schwarzschild black hole in modified gravity are analyzed with corresponding parameter values.
Article
Astronomy & Astrophysics
Sourabh Nampalliwar, Saurabh Kumar, Kimet Jusufi, Qiang Wu, Mubasher Jamil, Paolo Salucci
Summary: This paper investigates the impact of a dark matter spike on the vicinity of the black hole Sgr A* in the center of the Milky Way. The study examines the influence of dark matter density on the shadow radius and image of the black hole, concluding that the effect is weak for realistic densities but may become significant at higher densities near the black hole. However, simulations with radio interferometry, similar to an EHT array, suggest that detecting this effect in the near future is unlikely.
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
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)
Article
Astronomy & Astrophysics
Farruh Atamurotov, Kimet Jusufi, Mubasher Jamil, Ahmadjon Abdujabbarov, Mustapha Azreg-Ainou
Summary: This paper investigates the influence of axion-plasmon on the optical properties of Schwarzschild black hole. It is found that the size of the black hole shadow decreases with increasing axion-plasmon coupling, indicating changes in gravitational deflection angle and other properties.
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.