Article
Astronomy & Astrophysics
Priyanka Adhikary, Sudipta Das, Spyros Basilakos, Emmanuel N. Saridakis
Summary: The study discusses the construction of Barrow holographic dark energy in nonflat universe, deriving differential equations for the evolution of dark-energy density parameter and providing analytical expression for the dark energy equation-of-state parameter. The scenario is shown to describe the thermal history of the universe and the sequence of matter and dark energy epochs. Comparisons with flat cases and different spatial geometries reveal interesting behaviors in the evolution of dark-energy equation-of-state parameters under Barrow exponent variations. Incorporating slightly non-flat spatial geometry improves the phenomenology of Barrow holographic dark energy while maintaining smaller values for the new Barrow exponent.
Article
Astronomy & Astrophysics
Song Li, Yun Chen
Summary: In this study, a cosmological model within the framework of the Einstein-Cartan theory is considered. The corresponding relation between the torsion field and holographic dark energy is analyzed, revealing its behavior as quintessence or quintom dark energy. Stability analysis shows that the model is classically stable for c<1. The statefinder parameters also indicate a phase transition from deceleration to acceleration in the universe. The fitting with Type Ia supernovae samples confirms the compatibility of the model with the latest observations.
Article
Astronomy & Astrophysics
Abolhassan Mohammadi, Tayeb Golanbari, Kazuharu Bamba, Iarley P. Lobo
Summary: The application of holographic principle in early and late-time evolution, especially during inflation, shows that modifying entropy can result in changes in energy density. Through the use of Tsallis entropy and GO length scale, parameters of the model are calculated, establishing a correspondence between holographic dark energy and scalar field, and considering the trans-Planckian censorship conjecture.
Article
Physics, Mathematical
Pankaj, Nisha Muttathazhathu Ali, Umesh Kumar Sharma, P. Suresh Kumar, Shikha Srivastava
Summary: In this work, a new Tsallis holographic dark energy model with an apparent horizon as an infrared (IR) cutoff is constructed in a non-flat Friedmann-Lemaitre-Robertson-Walker Universe. The transition of the NTHDE Universe from a decelerating to an accelerating phase is described using the deceleration parameter and equation of state parameter with different values of the NTHDE parameter delta. The behavior of the equation of state parameter and the stability of the model are investigated using Hubble data sets and distance modulus measurements of Type Ia Supernovae.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Astronomy & Astrophysics
A. Remya, Umesh Kumar Pankaj, Umesh Kumar Sharma, Nisha Muttathazhathu Ali
Summary: We investigate the cosmological evolution of the Barrow holographic dark energy (BHDE) model in a non-flat universe using the FRW-metric with open and closed geometries. The scenario properly represents the thermodynamics of the universe with the evolution of matter and dark energy eras. The transition from decelerated to accelerated expansion phase is characterized by the dynamical properties of the deceleration parameter.
ASTROPHYSICS AND SPACE SCIENCE
(2023)
Article
Physics, Particles & Fields
P. Suresh Kumar, Bramha Dutta Pandey, Umesh Kumar Sharma, C. Pankaj
Summary: By extending the holographic principle to a cosmological framework and combining it with the Kaniadakis entropy, the non-flat Kaniadakis holographic dark energy model is constructed. The model describes the evolutionary behavior of the universe and can explain both open and closed universe models. It also provides insights into the thermal history of the universe and the quintom scenario.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Nisha Muttathazhathu Ali, Pankaj, Umesh Kumar Sharma, P. Suresh Kumar, Ambuj Kumar Mishra
Summary: In this study, a new Tsallis holographic dark energy model is constructed in a non-flat universe, considering the effects of different parameter values on the expansion of the universe. By deriving the differential equations for the dark energy density parameter and the equation of state parameter, it is found that there are specific behaviors in both closed and open universes, and the phase transition from deceleration to acceleration can be observed through the evolution of the deceleration parameter. The study shows that the model matches well with Hubble data and exhibits stability.
MODERN PHYSICS LETTERS A
(2022)
Article
Physics, Multidisciplinary
M. Zubair, Quratulien Muneer, Ertan Gudekli
Summary: In this study, we develop the counterpart of Tsallis holographic dark energy (THDE) model in F(7z, T) theory using two IR-cutoffs, Hubble horizon (HH) and Granda-Oliveros (GO). The stability analysis and constraints on the validity of the generalized second law of thermodynamics (GSLT) are studied for the reconstructed models. These reconstructed models are of great importance for further exploration of cosmic issues.
Article
Physics, Mathematical
A. Remya, Pankaj, Umesh Kumar Sharma
Summary: This work explores the cosmological scenario of Barrow holographic dark energy (BHDE) in relation to the time varying deceleration parameter. By investigating the evolution of a spatially flat Friedmann-Robertson-Walker (FRW) universe filled with pressure-less dark matter and BHDE density, the study analyzes the evolutionary history of essential cosmological parameters, such as the deceleration parameter, the equation of state parameter, and the density parameter. Additionally, the study examines the different structures of the model by reconstructing the scalar field potential to describe the universe's accelerated expansion phase.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2022)
Article
Physics, Multidisciplinary
Yang Liu
Summary: This paper explores the correlation between the tachyon dark energy model and the Tsallis holographic dark energy scenario in an FRW universe. It reveals key dynamics and potential of the scalar field in describing tachyon cosmology. The study indicates that for a flat universe, certain conditions must be satisfied for a constant equation of state, while a non-flat universe shows variations in parameters.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Physics, Nuclear
Sibel Korunur
Summary: In this study, we investigated Kaniadakis holographic dark energy (KHDE) in anisotropic and homogeneous Bianchi type-V universe. It was found that the equation of state (EoS) parameter transitions from the quintessence era to the phantom era for the chosen model. Additionally, in the late time of the universe, the EoS parameter behaves like a cosmological constant (lambda) with an apparent horizon having an IR cut-off for a specific form of deceleration parameter. We also established correspondences between KHDE and tachyon, quintessence, and k-essence scalar fields. Numerical solutions for the EoS parameter and scalar fields were visualized through graphs.
INTERNATIONAL JOURNAL OF MODERN PHYSICS A
(2022)
Article
Physics, Particles & Fields
Manuel Gonzalez-Espinoza, Giovanni Otalora
Summary: The cosmological dynamics of scalar-torsion f(T,phi) gravity as a dark energy model were investigated, focusing on non-linear coupling to gravity and exponential potential. Critical points of the autonomous system, stability conditions, and cosmological properties were obtained. New attractors with accelerated expansion and scaling solutions in relation to dark energy's energy density were shown, leading towards the dark energy-dominated era.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Zahra Bouabdallaoui, Ahmed Errahmani, Mariam Bouhmadi-Lopez, Taoufik Ouali
Summary: In this paper, warm inflation is considered in the context of holographic cosmology. The weak and strong dissipative regimes are analyzed within the slow-roll approximation and intermediate inflation. By considering several dissipative and physically relevant functions, the author constrains the model using the latest Planck data, and concludes that three of the models analyzed are consistent with the observations.
Article
Astronomy & Astrophysics
Biswajit Das, Biswajit Pandey
Summary: In this study, we theoretical investigate the one parameter Li holographic dark energy and the two parameter Barrow holographic dark energy models by analyzing the configuration entropy of matter distribution in the universe. We find that there is a distinct minimum of configuration entropy rate at a specific scale factor, which corresponds to the epoch when dark energy dominates the accelerated expansion of the universe. The location of the minimum and the magnitude of the entropy rate at the minimum are sensitive to the parameters of the models, and we propose using these relations to constrain the parameters of holographic dark energy models from future observations. Our study suggests that the large quantum gravitational effect on the future event horizon can be detected from measurements of the configuration entropy of matter distribution at multiple redshifts.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2023)
Article
Materials Science, Multidisciplinary
M. Koussour, N. Myrzakulov, S. Myrzakulova, D. Sofuoglu
Summary: This study proposes a novel parametrization approach for the dimensionless Hubble parameter in the context of scalar field dark energy models. The evolution of cosmological parameters is explored using observational data from Cosmic Chronometers, Baryonic Acoustic Oscillations, and the Pantheon+ datasets. The results are compared with the standard ΛCDM model.
RESULTS IN PHYSICS
(2023)
Article
Astronomy & Astrophysics
K. Fahimi, K. Karami, S. Asadzadeh, K. Rezazadeh
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2018)
Article
Physics, Particles & Fields
S. Rasouli, K. Rezazadeh, A. Abdolmaleki, K. Karami
EUROPEAN PHYSICAL JOURNAL C
(2019)
Article
Astronomy & Astrophysics
Saeid Karimi, Kayoomars Karami
ASTROPHYSICS AND SPACE SCIENCE
(2020)
Article
Astronomy & Astrophysics
Mohammad Sadeghi, Karam Bahari, Kayoomars Karami
Summary: In this paper, kink and sausage oscillations in the presence of longitudinal background flow were studied, with a focus on resonance absorption under magnetic pore conditions. The dispersion relation was determined and solved numerically to find frequencies and damping rates of the slow surface modes. It was shown that resonance absorption in the presence of plasma flow can lead to strong damping for forward waves while reducing the efficiency of damping for backward waves.
ASTROPHYSICAL JOURNAL
(2021)
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
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
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
Physics, Multidisciplinary
K. Rezazadeh, S. Asadzadeh, K. Fahimi, K. Karami, A. Mehrabi
Article
Astronomy & Astrophysics
Zanyar Ebrahimi, Roberto Soler, Kayoomars Karami
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Mohammad Sadeghi, Kayoomars Karami
ASTROPHYSICAL JOURNAL
(2019)
Article
Astronomy & Astrophysics
Zeinab Teimoori, Kayoomars Karami
ASTROPHYSICAL JOURNAL
(2018)
Article
Astronomy & Astrophysics
Roonak Amani, Kazem Rezazadeh, Asrin Abdolmaleki, Kayoomars Karami
ASTROPHYSICAL JOURNAL
(2018)
Article
Astronomy & Astrophysics
Zanyar Ebrahimi, Kayoomars Karami, Roberto Soler
ASTROPHYSICAL JOURNAL
(2017)
Article
Astronomy & Astrophysics
K. Rezazadeh, K. Karami, S. Hashemi
Article
Astronomy & Astrophysics
Kazem Rezazadeh, Asrin Abdolmaleki, Kayoomars Karami
ASTROPHYSICAL JOURNAL
(2017)
Article
Astronomy & Astrophysics
Nelson R. F. Braga, Octavio C. Junqueira
Summary: This study investigates the influence of rotation on the transition temperature of strongly interacting matter produced in non-central heavy ion collisions. By using a holographic description of an AdS black hole, the authors extend the analysis to the more realistic case where the matter spreads over a region around the rotational axis. The results show the coexistence of confined and deconfined phases and are consistent with the concept of local temperature in rotating frames developed by Tolman and Ehrenfest.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Astronomy & Astrophysics
Abdellah Touati, Zaim Slimane
Summary: This letter presents the first study of Hawking radiation as a tunneling process within the framework of non-commutative gauge theory of gravity. The non-commutative Schwarzschild black hole is reconstructed using the Seiberg-Witten map and the star product. The emission spectrum of outgoing massless particles is computed using the quantum tunneling mechanism. The results reveal pure thermal radiation in the low-frequency scenario, but a deviation from pure thermal radiation in the high-frequency scenario due to energy conservation. It is also found that noncommutativity enhances the correlations between successively emitted particles.
Article
Astronomy & Astrophysics
Shahar Hod
Summary: The travel times of light signals between two antipodal points on a compact star's surface are calculated for two different trajectories. It is shown that, for highly dense stars, the longer trajectory along the surface may have a shorter travel time as measured by asymptotic observers. A critical value of the dimensionless density-area parameter is determined for constant density stars to distinguish cases where crossing through the star's center or following a semi-circular trajectory on the surface has a shorter travel time as measured by asymptotic observers.