Article
Physics, Particles & Fields
Himanshu Chaudhary, Amine Bouali, Niyaz Uddin Molla, Ujjal Debnath, G. Mustafa
Summary: This paper investigates the observational signatures of f(R,G,T) gravity in the FRW universe and proposes a new cosmological model. By using the Markov Chain Monte Carlo technique, the model parameters are constrained, and various diagnostic tests and statistical analyses are conducted to evaluate the model's behavior and consistency with observational data. The findings highlight the potential and validity of the f(R,G,T) framework in understanding the dynamics and evolution of the universe.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Ujjal Debnath
Summary: The study investigates the gravitational waves phenomena for various dark energy models, obtaining solutions for energy densities of dark matter and dark energy components and analyzing the wave curves and power spectrums for different candidates of dark energy.
PHYSICS OF THE DARK UNIVERSE
(2021)
Article
Astronomy & Astrophysics
Xiao-Min Zhang, Kai Li, Yi-Fu Guo, Peng-Cheng Chu, He Liu, Jian-Yang Zhu
Summary: Two models proposed in this study unify warm inflation with dark matter and dark energy. A single scalar field is responsible for early Universe expansion through dissipative warm inflation and later acts as both dark matter and dark energy. Evolution equations for the fields and observational constraints are presented, along with an evolution law describing the scaling of energy density and state parameter with scale factor.
Article
Physics, Multidisciplinary
Vinod Kumar Bhardwaj, Priyanka Garg, Anirudh Pradhan, Syamala Krishnannair
Summary: In this study, we investigate the power-law entropy corrected holographic dark energy (PLECHDE) model with Hubble horizon cutoff. Using observational data, we constrain the model and calculate relevant cosmological parameters. The results show that the model is consistent with modern observations and matches well with current datasets.
CHINESE JOURNAL OF PHYSICS
(2022)
Article
Astronomy & Astrophysics
Raja Solanki, Avik De, P. K. Sahoo
Summary: In this study, the fundamental nature and evolution mechanism of dark energy in theoretical physics are explored using modified symmetric teleparallel gravity. The behavior of dark energy with different model parameters is analyzed, and it is found that it can exhibit quintessence or phantom scenario-like behavior. The study suggests that the geometrical generalization of general relativity can be a viable candidate for explaining the origin of dark energy.
PHYSICS OF THE DARK UNIVERSE
(2022)
Article
Physics, Particles & Fields
Sarfraz Ali, Sabir Iqbal, Khuram Ali Khan, Hamid Reza Moradi
Summary: This study explores the Renyi holographic dark energy model in the theory of Chern-Simons modified gravity, revealing how changes in the equation of state and deceleration parameter can explain the evolution of the universe, with dark energy playing a crucial role in cosmic expansion.
ADVANCES IN HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Molly Burkmar, Marco Bruni
Summary: This article explores the dynamics of FLRW cosmologies with dark matter, radiation, and dark energy using a quadratic equation of state. It focuses on nonsingular bouncing and cyclic cosmologies, particularly examining the possibility of closed FLRW models always having a bounce for any initial conditions. The study identifies a class of closed models that exhibit a nonsingular bounce with both early- and late-time accelerated expansion connected by a decelerating phase. However, it is found that these bouncing models are only relevant when dark matter and radiation appear at a specific energy scale, requiring a period of reheating.
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
Physics, Multidisciplinary
Himanshu Chaudhary, Amine Bouali, Ujjal Debnath, Tanusree Roy, G. Mustafa
Summary: Confirmation of accelerated expansion of the Universe has led to the introduction of numerous models to explain dark energy. This study focuses on reconstructing dark energy by parameterizing the deceleration parameter in the FLRW universe filled with radiation, dark matter, and dark energy. Different parametrized models and cosmological parameters are estimated using observational datasets, and their viability is examined using information criteria.
Article
Multidisciplinary Sciences
Cosmin Andrei, Anna Ijjas, Paul J. Steinhardt
Summary: In this paper, we investigate how short the remaining period of expansion can be given current observational constraints on dark energy, and discuss how this scenario fits naturally with cyclic cosmologies and recent conjectures about quantum gravity.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Astronomy & Astrophysics
Alexander C. Ritter, Raymond R. Volkas
Summary: This study explores the possibility of a natural mass relationship in symmetric dark matter models, and the use of dark electroweak baryogenesis as a means of generating asymmetry. By investigating the nature of the dark electroweak phase transition and the transfer of particle asymmetries through portal interactions, it is found that both aspects can be successfully implemented in various regions of the parameter space. Further analysis is conducted on the neutron portal interaction to meet observational constraints on dark radiation.
Article
Physics, Multidisciplinary
Amine Bouali, Himanshu Chaudhary, Saadia Mumtaz, G. Mustafa, S. K. Maurya
Summary: In this study, a dark energy (DE) model reconstructed from the deceleration parameter (DP) is analyzed. A flat FRW Universe with radiation, dark matter, and dark energy fluids is considered. The model is constrained using measurements from various sources and is found to be well-supported by observations compared to ΛCDM. Additionally, cosmographic and diagnostic analyses are performed, showing similar behavior to ΛCDM and quintessence type behavior at a late time, respectively.
FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS
(2023)
Article
Astronomy & Astrophysics
Fei Huang, Veronica Sanz, Jing Shu, Xiao Xue
Summary: The article demonstrates how current LIGO data can probe interesting theories beyond the Standard Model, particularly dark sectors where a dark Higgs boson triggers symmetry breaking via a first-order phase transition. It shows that the LIGO measurements are testing a broad set of scenarios in the dark sector models with reasonable parameters for the scalar potential.
Article
Astronomy & Astrophysics
Ashadul Halder, Shashank Shekhar Pandey, A. S. Majumdar
Summary: We examine the global 21-cm brightness temperature in the context of viscous dark energy models and study the effects of Hawking radiation, decay and annihilation of particle dark matter, and baryon-dark matter scattering on the temperature. Our analysis provides bounds on the parameters of the viscous dark energy model that can account for the observed excess in the EDGES experiment. Additionally, our study yields modified constraints on the dark matter mass and scattering cross-section compared to the conventional ACDM model.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Rownak Kundu, Ujjal Debnath, Anirudh Pradhan
Summary: In this study, we investigated the behavior of non-interacting dark energy and dark matter in a non-flat FRW model. We examined various dark energy models, including Tachyonic Field, Generalized Cosmic Chaplygin Gas, New Variable Modified Chaplygin Gas, Modified Chaplygin-Jacobi Gas, and Modified Chaplygin-Abel Gas. Our analysis focused on the optical depth behavior of these models with different cosmological parameters, and we presented the results graphically. Furthermore, we compared our findings in both flat and non-flat universes with the ACDM model.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
S. H. Shekh, A. Bouali, G. Mustafa, A. Pradhan, F. Javed
Summary: In this study, the f(Q) gravity theory is used to analyze the rapid expansion of the Universe. The non-metricity scalar Q is the key parameter characterizing the gravitational interaction. By considering various observational data, we evaluate the model parameters and find that the Universe is currently in the acceleration phase. Additionally, we study different f(Q) gravity models and investigate their implications for cosmological parameters.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Physics, Multidisciplinary
Archana Dixit, Chanchal Chawla, Anirudh Pradhan
Summary: This paper discusses the cosmic expansion in a universe filled with viscous fluid in Bianchi type-I space-time. By solving Einstein's field equations, a time-varying deceleration parameter and scale factor are obtained. Two different viscous cosmological models are constructed based on different constraints. The models show good agreement with recent observations and exhibit interesting features such as a decreasing dark energy candidate.
CANADIAN JOURNAL OF PHYSICS
(2023)
Article
Physics, Mathematical
Archana Dixit, Priyanka Garg, Anirudh Pradhan
Summary: In this paper, the general behaviors of the Tsallic holographic dark energy (THDE) model in general relativity are investigated. The THDE models with the Hubble horizon and Granda-Oliveros (GO) cutoffs are studied using the Bianchi V I-0 metric, which is homogeneous and anisotropic. The behaviors and physical significances of quantities such as dark energy density (rho(D)), matter-energy density (rho(m)), and skewness parameter (gamma) are analyzed. Cosmographic parameters and the stability analysis of the THDE model are also discussed.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Mathematical
Anirudh Pradhan, Gopikant Goswami, Aroonkumar Beesham
Summary: In this paper, a Friedmann-Lemaitre-Robertson-Walker model in f(R, T) gravity is constructed with a perfect fluid that leads to acceleration at late times. The matter is divided into two components: Omega(m) and Omega(mu). Omega(mu) is dominant over Omega(m) at present, and their ratio depends on different data sets. The pressures and densities associated with the two matter densities are also calculated, and it is found that rho(mu) is greater than rho(m) currently.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Multidisciplinary
Anirudh Pradhan, Gopikant Goswami, Syamala Krishnannair
Summary: We have developed a Bianchi I cosmological model in f (R, T) gravity theory that matches well with the current acceleration of the universe. The model shows a transition from deceleration in the past to acceleration at present. We have defined three energy parameters, Omega(m), Omega(mu), and Omega(sigma), where Omega(mu) is dominant. We used observational data sets to estimate various parameters and calculated the pressures, densities, and the age of the universe.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Microbiology
Subhankar Mukherjee, Punyasloke Bhadury, Shravani Mitra, Sharmi Naha, Bijan Saha, Shanta Dutta, Sulagna Basu
Summary: This study characterized hvKP/CR-hvKP strains causing neonatal sepsis in terms of resistance and virulence. About 26% of the strains belonged to hvKP, with hvKP-K2 being the prevalent pathotype. The majority of the strains exhibited strong biofilm-forming and high serum resistance ability. Additionally, this study reported for the first time the NDM-1-producing hvKP ST11-K2 and ST15-K54 strains causing fatal neonatal sepsis.
MICROBIOLOGY SPECTRUM
(2023)
Article
Astronomy & Astrophysics
Bijan Saha
Summary: In this study, the role of a nonlinear spinor field in the evolution of the universe within a FLRW cosmological model is investigated. The FLRW models in both Cartesian and spherical coordinates are used. It is observed that the energy-momentum tensor of the spinor field has non-diagonal components when the FLRW model is given in spherical coordinates, which is not the case for Cartesian coordinates. These non-diagonal components are independent of both the nonlinearity of the spinor field and the curvature parameter k. The presence of these components imposes constraints on the spinor field. Open, flat, and closed geometries are considered, and the spinor field is used to simulate different types of sources including dark energies. Some qualitative numerical solutions are provided.
Article
Astronomy & Astrophysics
S. H. Shekh, H. Chaudhary, A. Bouali, A. Dixit
Summary: It has been observed that the current Universe is experiencing accelerated expansion. To analyze this, a new theory of gravity was used, involving the torsion scalar as the cause of accelerated expansion. By comparing the model with observational data, the best fitting parameter values were determined and the behavior of the deceleration parameter and equation of state parameter were studied in relation to these values.
GENERAL RELATIVITY AND GRAVITATION
(2023)
Article
Physics, Mathematical
Takol Tangphati, Grigoris Panotopoulos, Ayan Banerjee, Anirudh Pradhan
Summary: By constructing models of quark stars (QSs) using the MIT bag model, this paper explores the internal structure and physical properties of QSs in the context of the four-dimensional Einstein-Gauss-Bonnet (EGB) theory of gravity. The results show that all studied cases are consistent with observations and physically relevant.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Mathematical
M. Zeyauddin, Archana Dixit, Anirudh Pradhan
Summary: This paper investigates an anisotropic Bianchi type-I dark energy universe model in f (R, L-m) gravity with observational constraints. The field equations are solved analytically and a relationship between energy parameters Omega(m), Omega(k), Omega(Lambda) and Hubble function H(z) is established. The best fit values of model parameters and energy parameters are obtained by comparing the Hubble function with observational datasets.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Mathematical
Alok Sardar, Pameli Saha, Ujjal Debnath, Anirudh Pradhan
Summary: The prediction of the accelerating expansion of the universe led to the discovery of dark energy. Since then, researchers have been working on understanding the origin and nature of dark energy. In this study, the possibility of cosmic acceleration through a new kind of dark energy called Yang-Mills condensate dark energy is explored in the generalized Brans-Dicke theory. The model investigates different scenarios of variable or constant omega (Brans-Dicke parameter) and the presence or absence of self-interacting potential to determine whether the universe is currently accelerating. The analysis includes studying the equation of state parameter, the omega D - omega'(D) analysis, and the stability of the model.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Mathematical
Anirudh Pradhan, Archana Dixit, Sanjeev Gupta
Summary: This paper investigates the cosmological applications of the modified gravitational theory based on torsion invariant and Gauss-Bonnet term. The study explores the viability of the alternative gravitational theory and constrains the model parameters using observational datasets. The results demonstrate that the model satisfies essential features and exhibits intriguing cosmological behavior.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Multidisciplinary Sciences
A. P. Kale, Y. S. Solanke, S. H. Shekh, A. Pradhan
Summary: This study examines the f(Q, T) theory of gravity, discusses two different forms of the theory, analyzes the physical properties of the models, and obtains the best-fit values using the least squares method.
Article
Physics, Multidisciplinary
Bijan Saha
Summary: Within the Bianchi type-II cosmological model, the role of a spinor field in the evolution of the Universe was studied. It was found that even in the absence of spinor field nonlinearity, the components of the spinor field's energy-momentum tensor along the principal axis were different. The presence of nontrivial non-diagonal components of the energy-momentum tensor imposed restrictions on both the geometry of space-time and the spinor field itself. The choice of f(x3) determined whether the space-time was locally rotationally symmetric or isotropic. Depending on this choice, positive lambda(1) with f f''not equal 0 resulted in an oscillatory mode of evolution, while f' not equal 0 led to an accelerated mode of expansion.
ROMANIAN JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
A. Dixit, V. K. Bhardwaj, A. Pradhan, S. Krishnannair
Summary: In this paper, we discuss the cosmological consequences of the f(R) dark energy scenario in the context of strange quark matter with string clouds in the Kantowski-Sachs space-time. We derive the physical parameters and describe their behavior using graphical representations. To obtain a deterministic solution, we consider a time-dependent scale factor and assume a linear relationship between the deceleration parameter and the Hubble parameter. We find constraints on H-0 and beta using 57 observational Hubble data sets (OHD) and obtain an explicit form of the function f(R) that satisfies cosmological viability constraints. We also examine the validity of the energy conditions.
INDIAN JOURNAL OF PHYSICS
(2023)
