Article
Physics, Multidisciplinary
Joaquin Estevez-Delgado, Joel Arturo Rodriguez Ceballos, Jorge Mauricio Paulin-Fuentes, Jose Vega Cabrera, Antonio Rendon Romero
Summary: This report generalizes the solution to Einstein's equations with perfect fluid to the case of Einstein-Maxwell with perfect fluid. The effect of the charge is determined by a parameter ν, which is constrained by the positivity condition from the pressure inside the star. It is shown that the solution is stable according to the Zeldovich criteria and the adiabatic index criteria. The presence of charge increases the compactness of the model, allowing it to represent stars with high compactness.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Bikram Keshari Parida, Shreya Majumder, Shyam Das, Koushik Chakraborty, Farook Rahaman
Summary: We obtained a new class of solutions for a relativistic anisotropic compact star using the Karmarkar embedding condition. By analyzing the Karmarkar condition, a suitable form of one of the gravitational potentials has been chosen to determine the closed-form solution for the other. The resulting solutions are well-behaved and could describe a compact stellar object. Considering the current estimated values of the mass and radius of the pulsar 4U1820 - 30 as input parameters, all the physically relevant parameters are shown to be well-behaved to a very good degree of accuracy.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2023)
Article
Astronomy & Astrophysics
Aurelio Tamez Murguia, Manuel Vazquez-Nambo, Victor Manuel Yepez-Garcia, Nancy Cambron Munoz, Jose Oswald Tellez Vazquez
Summary: This work presents an exact interior solution to an Einstein-Maxwell equation system, which assumes a static and spherically symmetric spacetime with a distribution of matter representing a generalization of a model for a perfect chargeless fluid. The charge parameter modifies the mass function, compactness rate, and behavior of the speed of sound. The analysis of density, pressure, and charge shows that the solution is suitable for describing relativistic compact stars. Specifically, the behavior of these functions is analyzed for observed mass values in the range [0.95, 1.13] solar masses and theoretical radius values in the range [8.101, 8.501] km for the star LMC X-4. The maximum charge value Q - 1.73 x 10(20)C occurs at the maximum compactness u = 0:2059.
MODERN PHYSICS LETTERS A
(2023)
Article
Physics, Multidisciplinary
Umber Sheikh, Kashif Mahmood, M. Arshad
Summary: The study investigates the gravitational collapse of charged imperfect fluids, showing that string tension affects all physical parameters of the fluid. It also concludes that density and electric field intensity increase while fluid pressure decreases near singularity formation.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Multidisciplinary Sciences
Colin Rogers, Wolfgang Karl Schief
Summary: It is stated that the classical Taub system for isentropic planar motions of perfect fluids in special relativity can be fully explained using soliton theory. Therefore, the well-established tools of integrable systems theory can be used to produce a wide range of solutions in parametric form. As an example, the general solution of the Taub system with a specific pressure-density constitutive law can be obtained by applying a binary Darboux transformation to the seed solution of the Taub system describing extreme fluids.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Physics, Multidisciplinary
Gabino Estevez-Delgado, Joaquin Estevez-Delgado, Rafael Soto-Espitia, Antonio Rendon Romero, Jorge Mauricio Paulin-Fuentes
Summary: In this paper, we present an analytical solution to the Einstein-Maxwell field equations for a static and spherically symmetric geometry with anisotropic pressures. The solution is obtained using the Karmarkar condition and considers matter with quark interactions and electric charge. The physical properties of the model are analyzed graphically using observational data for the star Her X-1, and the stability of the solution is demonstrated through stability criteria.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2023)
Article
Astronomy & Astrophysics
Simranjeet Kaur, Sacheendra Shukla
Summary: This paper presents a new family of interior solutions of the Einstein-Maxwell field equations in general relativity for modeling superdense stars, with well-behaved behavior for a wide range of parameters. The solution is validated and compared with specific stars, showing maximum and minimum surface redshift values. Rigorous physical viability tests were conducted, resulting in a regular and well-behaved model in the absence of charge.
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2022)
Article
Astronomy & Astrophysics
Kai Shi, Yu Tian, Xiaoning Wu, Hongbao Zhang, Jingchao Zhang
Summary: In this paper, we analyze the dynamic and thermodynamic stability of a charged perfect fluid star using the Wald formalism applied to the Lagrangian formulation of the Einstein-Maxwell-charged fluid system. We find that the presence of additional electromagnetic field and the Lorentz force experienced by the charged fluid do not obstruct the key steps towards the previous results on neutral perfect fluid star. The results show that the dynamic stability of the charged star in dynamic equilibrium is determined by the non-negativity of the canonical energy associated with the timelike Killing field, while the thermodynamic stability is determined by the positivity of the canonical energy of linear on-shell perturbations.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Mechanics
Mark Watson
Summary: This study outlines the analogy of the effect of obstacles on the flow of massless charge carriers in graphene, similar to the wake effect of wind turbines in wind farms. Using relativistic hydrodynamic simulation, evidence of potentially turbulent flow is found in samples with impurities, and the experimental consequences are discussed.
Article
Physics, Multidisciplinary
C. P. Felix, E. S. Moreira Jr
Summary: This paper presents a toy model of a charged relativistic classical gas in flat space-time of an arbitrary number of dimensions equipped with some pair production mechanism. The thermodynamics of the classical gas is studied in both the nonrelativistic and ultrarelativistic regimes. It is shown that, although dealing with classical distributions, the behavior of the gas is Planckian in the ultrarelativistic regime. The thermodynamics of the toy model is also compared with that of quantum gases.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2023)
Article
Astronomy & Astrophysics
Mithun Ghosh
Summary: By modeling the mass density function within the galactic halo region, the flat rotational velocity of spiral galaxies can be explained, leading to a solution consistent with modern cosmological observations. Additionally, the attractive gravity and stability of circular orbits in the halo region were also analyzed.
MODERN PHYSICS LETTERS A
(2021)
Article
Astronomy & Astrophysics
Anish Das, Ashis Saha, Sunandan Gangopadhyay
Summary: In this study, a charged black hole solution in the presence of perfect fluid dark matter (PFDM) was obtained and its energy conditions were discussed. The corresponding rotating metric was obtained using the Newman-Janis algorithm, and circular geodesics were calculated to study the effects of black hole parameters on particle energy. The study also delved into the Penrose process and the potential existence of negative energy particles within the ergosphere.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Computer Science, Interdisciplinary Applications
Takayuki Umeda
Summary: A new explicit numerical scheme is proposed as an alternative to the Boris integrator for integrating the relativistic equations of motion for charged particles. The present integrator approximates the theoretical trajectory of the relativistic E-cross-B motion more accurately than previous explicit integrators such as Boris, Vay, and Higuera-Cary ones.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Physics, Mathematical
Mohd Danish Siddiqi, Uday Chand De
Summary: This research paper investigates the Ricci-Yamabe soliton on a perfect fluid space-time with a torse-forming vector field, and explores the specific case when the potential vector field is of the gradient type.
LETTERS IN MATHEMATICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Tufail Ahmad
Summary: The article reports on pseudo-central collision events observed in pion-nucleus interactions, where particles are produced in clusters independently of the incident beam and energy. Shortshort rapidity-gap correlation seems to dominate over short-long correlation in these events, while central and normalized moments of relativistic charged particles display different trends compared to inclusive data.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
Neeraj Pant, Satyanarayana Gedela, Ravindra K. Bisht
Summary: The paper aims to find an anisotropic and charged version of the Heintzmann interior solution in a space-time using the minimal geometric deformation approach to gravitational decoupling. Through various physical tests, the obtained model of neutron star 4U1608-52 proves to be a well-behaved physical solution to Einstein-Maxwell's field equations.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Astronomy & Astrophysics
Satyanarayana Gedela, Neeraj Pant, Jaya Upreti, R. P. Pant
Summary: This paper presents a new parametric class of solutions to study the relativistic structure of compact stars via embedding class I condition. The interior of the star is delineated by Karmarkar condition and matched with Bardeen and Reissner-Nordstrom exterior spacetimes. By solving Maxwell field equations, all thermodynamic properties are verified and compared.
MODERN PHYSICS LETTERS A
(2021)
Article
Physics, Multidisciplinary
Satyanarayana Gedela, Neeraj Pant, Megandhren Govender
Summary: In this paper, a new exact anisotropic charged version of Pant's interior solution is presented, integrating coupled Einstein-Maxwell field equations to generate a family of new charged anisotropic solutions. Rigorous tests were conducted to validate the physical viability of the model, showing the intrinsic connection between the deformation parameter and key features.
BRAZILIAN JOURNAL OF PHYSICS
(2021)
Article
Astronomy & Astrophysics
Saibal Ray, Prasenjit Paul, Rikpratik Sengupta, Neeraj Pant, Riju Nag
Summary: This paper investigates anisotropic universes with Modified Chaplygin gas in the context of the Randall Sundrum-2 braneworld model. Solutions for Kantowski-Sachs and Bianchi-I universes with MCG are obtained, showing modifications from GR solutions due to the braneworld correction term. The possibility of future singularities is considered, with the model overcoming some drawbacks of the relativistic framework.
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2021)
Article
Astronomy & Astrophysics
Satyanarayana Gedela, Ravindra K. Bisht, Neeraj Pant, Jaya Upreti, R. P. Pant
Summary: In this paper, two new exact and analytic solutions are presented for compact anisotropic charged stars in the background of Bardeen black hole geometry satisfying the Karmarkar condition. The models consist of inner region described by class I Karmarkar space-time and exterior characterized by both Bardeen and Reissner-Nordstrom spacetimes. Analysis shows that the models are well-behaved in terms of matter and thermodynamic variables.
Article
Astronomy & Astrophysics
Ravindra K. Bisht, Satyanarayana Gedela, Neeraj Pant, Neeraj Tewari
Summary: This work presents a novel solution for neutron stars with different layers of matter and equations of state, showing continuous and feasible trends in physical and geometrical parameters. The model meets various stability conditions, providing a more realistic and accurate modeling of stellar objects.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Neeraj Pant, Megandhren Govender, Satyanarayana Gedela
Summary: This work presents a theoretical framework within Einstein's classical general relativity to model stellar compact objects, with the assumption of a class I spacetime for the interior structure and the adoption of a robust gravitational potential form. The model satisfies all the requirements for physically realistic stellar structures.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Neeraj Pant, Satyanarayana Gedela, Saibal Ray, Kumar Gaurav Sagar
Summary: This paper explores a solution to the Einstein-Maxwell field equations in four-dimensional spacetime by using the Karmarkar conditions and the minimal geometric decoupling technique. The obtained solution is shown to be physically viable for neutron stars.
MODERN PHYSICS LETTERS A
(2022)
Article
Astronomy & Astrophysics
Kumar Gaurav Sagar, Brajesh Pandey, Neeraj Pant
Summary: The paper proposes a hybrid stellar model consisting of gravitating baryonic matter and a linearly coupled repulsive dark energy field by using Einstein field equations. The physical viability of the solutions is analyzed, revealing that dark energy can provide stability against gravitational collapse.
ASTROPHYSICS AND SPACE SCIENCE
(2022)
Article
Astronomy & Astrophysics
Shweta Saklany, Neeraj Pant, Brajesh Pandey
Summary: The main aim of this study is to investigate the influence of background dark energy on a gravitationally compact star, PSRJ0740 + 6620. The Einstein field equations are used in an anisotropic regime to model the space-time fabric and associated gravity. The spatial metric potential of Vaidya-Tikekar type is utilized to obtain the temporal metric potential using Karmarkar's connecting relation and the unknown constants are calculated using Darmois-Israel conditions. Through rigorous theoretical analysis, it is found that the model star satisfies all the necessary and sufficient conditions to form a viable stellar configuration. The key findings suggest that the background repulsive scalar field of dark energy can aid in the formation of dense and stable stellar structures at masses beyond the TOV limit.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
Shweta Saklany, Neeraj Pant, Brajesh Pandey
Summary: A singularity free and smoothly connected complete solution for a three-layered compact star is presented, including a deconfined quark matter core, a coherent quantum fluid, and a repulsive neutron-Coulomb fluid envelope. Insights into the pressure-density distribution and thermodynamic properties are obtained, shedding light on the structural stability and mass-radius relation.
Article
Astronomy & Astrophysics
Shweta Saklany, Brajesh Pandey, Neeraj Pant
Summary: This study provides a simulation of the coupling of dark energy and baryonic matter using a super-dense pulsar as the model star. The analysis of various physical parameters indicates stable star formation. The proposed stellar model is free from singularities and meets the requisite stability criteria.
MODERN PHYSICS LETTERS A
(2022)
Article
Physics, Multidisciplinary
K. N. Singh, F. Rahaman, N. Pant
Summary: This paper proposes a three-layered hybrid compact star model, with a quark matter core, neutron liquid intermediate layer, and matter envelope satisfying a quadratic EoS. By tuning free parameters, physical parameters are continuous across regions, but stability is not defined at interfaces. Calculations verify a smooth transition density between different regions.
INDIAN JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
S. Gedela, R. K. Bisht, N. Pant
Summary: This paper introduces a new class of exact solutions that satisfy Einstein's field and modified TOV equations, using the Karmarkar condition. The solutions meet various stability criteria and energy conditions, and a complete graphical analysis of neutron stars in the Karmarkar space-time is performed.
INDIAN JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
K. N. Singh, F. Rahaman, N. Pradhan, N. Pant
Summary: The study presents an anisotropic charged analogue solution which can be used to model various types of compact stars, such as quark stars and neutron stars. By adjusting parameters, specific models for super-dense quark stars and neutron stars are obtained, showing that the increase in charge and anisotropy can enhance the stability of configurations.
INDIAN JOURNAL OF PHYSICS
(2021)