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Gravitational Collapse and Expansion in the Newton Theory and General Relativity
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作者 Valery V. Vasiliev Leonid V. Fedorov 《Journal of Modern Physics》 2025年第2期294-309,共16页
The paper is devoted to the study of the gravitational collapse within the framework of the spherically symmetric problem in the Newton theory and general relativity on the basis of the pressure-free model of the cont... The paper is devoted to the study of the gravitational collapse within the framework of the spherically symmetric problem in the Newton theory and general relativity on the basis of the pressure-free model of the continuum. In application to the Newton gravitation theory, the analysis consists of three stages. First, we assume that the gravitational force is determined by the initial sphere radius and constant density and does not change in the process of the sphere collapse. The obtained analytical solution allows us to find the collapse time in the first approximation. Second, we construct the step-by-step process in which the gravitational force at a given time moment depends on the current sphere radius and density. The obtained numerical solution specifies the collapse time depending on the number of steps. Third, we find the exact value of the collapse time which is the limit of the step-by-step solutions and study the collapse and the expansion processes in the Newton theory. In application to general relativity, we use the space model corresponding to the special four-dimensional space which is Euclidean with respect to space coordinates and Riemannian with respect to the time coordinate only. The obtained solution specifies two possible scenarios. First, sphere contraction results in the infinitely high density with the finite collapse time, which does not coincide with the conventional result corresponding to the Schwarzschild geometry. Second, sphere expansion with the velocity which increases with a distance from the sphere center and decreases with time. 展开更多
关键词 Gravitational Collapse Newton Gravitation Theory general relativity
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Remarks on the Total Angular Momentum in General Relativity 被引量:2
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作者 ZHANGXiao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第5期521-524,共4页
We verify that the total angular momentum 3-vector defined by the author [X. Zhang, Commun. Math.Phys. 206 (1999) 137] is equal to (0, 0, ma) forany time slice in both the Kerr and the Kerr-Newman spacetimes.
关键词 total angular momentum general relativity
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Continuum Mechanics of Space Seen from the Aspect of General Relativity An Interpretation of the Gravity Mechanism 被引量:1
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作者 Yoshinari Minami 《Journal of Earth Science and Engineering》 2015年第3期188-202,共15页
A mechanical structure of space is suggested. On the supposition that a space as vacuum has a physical fine structure like continuum, it enables us to apply a continuum mechanics to the so-called "vacuum" of space. ... A mechanical structure of space is suggested. On the supposition that a space as vacuum has a physical fine structure like continuum, it enables us to apply a continuum mechanics to the so-called "vacuum" of space. A space is an infinite continuum and its structure is determined by Riemannian geometry. Assuming that space is an infmite continuum, the pressure field derived from the geometrical structure of space is newly obtained by applying both continuum mechanics and General Relativity to space. A fundamental concept of space-time is described that focuses on theoretically innate properties of space including strain and curvature. As a trial consideration, gravity can be explained as a pressure field induced by the curvature of space. 展开更多
关键词 general relativity continuum mechanics CURVATURE strain SPACE-TIME gravity.
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On the Field Equations of General Relativity 被引量:1
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作者 Vu B. Ho 《Journal of Applied Mathematics and Physics》 2022年第1期49-55,共7页
In this work, we examine the geometric character of the field equations of general relativity and propose to formulate relativistic field equations in terms of the Riemann curvature tensor. The resulted relativistic f... In this work, we examine the geometric character of the field equations of general relativity and propose to formulate relativistic field equations in terms of the Riemann curvature tensor. The resulted relativistic field equations are also integrated into the general framework that we have presented in our previous works that all known classical fields can be expressed in the same dynamical form. We also discuss a possibility to reformulate the field equations of general relativity so that the Ricci curvature tensor and the energy-momentum tensor can appear symmetrically in the field equations without violating the conservation law stated by the covariant derivative. 展开更多
关键词 general relativity Classical Field Equations Riemann Curvature Tensor
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Class of Charged Fluid Balls in General Relativity 被引量:2
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作者 A. Sah Prakash Chandra 《International Journal of Astronomy and Astrophysics》 2016年第4期494-511,共18页
In the present study, we have obtained a new analytical solution of combined Einstein-Maxwell field equations describing the interior field of a ball having static spherically symmetric isotropic charged flu... In the present study, we have obtained a new analytical solution of combined Einstein-Maxwell field equations describing the interior field of a ball having static spherically symmetric isotropic charged fluid within it. The charge and electric field intensity are zero at the center and monotonically increasing towards the boundary of the fluid ball. Besides these, adiabatic index is also increasing towards the boundary and becomes infinite on it. All other physical quantities such as pressure, density, adiabatic speed of sound, charge density, adiabatic index are monotonically decreasing towards the surface. Causality condition is obeyed at the center of ball. In the limiting case of vanishingly small charge, the solution degenerates into Schwarzchild uniform density solution for electrically neutral fluid. The solution joins smoothly to the Reissner-Nordstrom solution over the boundary. We have constructed a neutron star model by assuming the surface density . The mass of the neutron star comes  with radius 14.574 km. 展开更多
关键词 Exact Solution Einstein’s Field Equations Charged Fluid Ball Compact Star general relativity
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Spherical Anisotropic Fluid Distribution in General Relativity 被引量:1
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作者 A. Sah Prakash Chandra 《World Journal of Mechanics》 2016年第12期487-504,共18页
In the present investigation of a spherically symmetric electrically neutral anisotropic static fluid, we present a new solution of the Einstein’s general relativistic field equations. The solution shows positive fin... In the present investigation of a spherically symmetric electrically neutral anisotropic static fluid, we present a new solution of the Einstein’s general relativistic field equations. The solution shows positive finite central pressures, central density and central red shift. The causality condition is obeyed at the centre. The anisotropy parameter is zero at the center and monotonically increasing toward the surface. The adiabatic index is also increasing towards the surface. All the other physical quantities such as matter-energy density, radial pressure, tangential pressure, velocity of sound and red shift are monotonically decreasing towards the surface. Further by assuming the surface density , we have constructed a model of massive neutron star with mass 2.95 with radius 18 km with all degree of suitability. 展开更多
关键词 Anisotropic Fluid Ball Exact Solutions Einsteins Field Equations Compact Star general relativity
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Addition to the Article with Stepan Moskaliuk on the Inter Relationship of General Relativity and (Quantum) Geometrodynamics, via Use of Metric Uncertainty Principle 被引量:1
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作者 Andrew Walcott Beckwith 《Journal of High Energy Physics, Gravitation and Cosmology》 2016年第4期467-471,共5页
We take note of the material offered in [1] as to Geometrodynamics as a way to quantify an inter relationship between a quantum style Heisenberg uncertainty principle for a metric tensor and conditions postulated as t... We take note of the material offered in [1] as to Geometrodynamics as a way to quantify an inter relationship between a quantum style Heisenberg uncertainty principle for a metric tensor and conditions postulated as to a barotropic fluid, i.e. dust for early universe conditions. By looking at the onset of processes at/shorter than a Planck Length, in terms of initial expansion of the universe, we use inputs from the metric tensor as a starting point for the variables used in Geometrodynamics. 展开更多
关键词 general relativity GEOMETRODYNAMICS Metric Uncertainty Principle
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A Locally Conservative Energy-Momentum Tensor in the General Relativity Based on a Cosmological Model without Singularity 被引量:1
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作者 Shihao Chen 《Journal of Modern Physics》 2016年第3期277-280,共4页
According to the conventional theory it is difficult to define the energy-momentum tensor which is locally conservative. The energy-momentum tensor of the gravitational field is defined. Based on a cosmological model ... According to the conventional theory it is difficult to define the energy-momentum tensor which is locally conservative. The energy-momentum tensor of the gravitational field is defined. Based on a cosmological model without singularity, the total energy-momentum tensor is defined which is locally conservative in the general relativity. The tensor of the gravitational mass is different from the energy-momentum tensor, and it satisfies the gravitational field equation and its covariant derivative is zero. 展开更多
关键词 Energy-Momentum Tensor of Gravitational Field Locally Conservative Energy-Momentum Tensor in general relativity Tensor of the Gravitational Mass Quasi-Local Energy-Momentum Tensor
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Trace Formulae of Characteristic Polynomial and Cayley-HamUton's Theorem, and Applications to Chiral Perturbation Theory and General Relativity
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作者 ZHANG Hong-Hao YAN Wen-Bin LI Xue-Song 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第4期801-808,共8页
By using combinatorics, we give a new proof for the recurrence relations of the characteristic polynomial coefficients, and we further obtain an explicit expression for the generic term of the coefficient sequence, wh... By using combinatorics, we give a new proof for the recurrence relations of the characteristic polynomial coefficients, and we further obtain an explicit expression for the generic term of the coefficient sequence, which yields the trace formulae of the Cayley-Hamilton's theorem with all coefficients explicitly given. This implies a byproduct, a complete expression for the determinant of any finite-dimensional matrix in terms of the traces of its successive powers. And we discuss some of their applications to ehiral perturbation theory and general relativity. 展开更多
关键词 characteristic polynomial coefficients Cayley-Hamilton's theorem chiral perturbation theory general relativity
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Gravitational radiation fields in teleparallel equivalent of general relativity and their energies
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作者 Gamal G.L.Nashed 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第11期132-139,共8页
We derive two new retarded solutions in the teleparallel theory equivalent to general relativity (TEGR). One of these solutions gives a divergent energy. Therefore, we use the regularized expression of the gravitati... We derive two new retarded solutions in the teleparallel theory equivalent to general relativity (TEGR). One of these solutions gives a divergent energy. Therefore, we use the regularized expression of the gravitational energymomentum tensor, which is a coordinate dependent. A detailed analysis of the loss of the mass of Bondi space-time is carried out using the flux of the gravitational energy-momentum. 展开更多
关键词 teleparallel equivalent of general relativity energy-momentum tensor Bondi mass gravitational radiation
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Energy,momentum and angular momentum in the dyadosphere of a charged spacetime in teleparallel equivalent of general relativity
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作者 Gamal G.L.Nashed 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第3期85-91,共7页
We apply the energy momentum and angular momentum tensor to a tetrad field, with two unknown functions of radial coordinate, in the framework of a teleparallel equivalent of general relativity (TEGR). The definition... We apply the energy momentum and angular momentum tensor to a tetrad field, with two unknown functions of radial coordinate, in the framework of a teleparallel equivalent of general relativity (TEGR). The definition of the gravitational energy is used to investigate the energy within the external event horizon of the dyadosphere region for the Reissner-NordstrSm black hole. We also calculate the spatial momentum and angular momentum. 展开更多
关键词 Teleparallel equivalent of general relativity energy-momentum tensor angular momen- tum tensor angular momentum
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Cosmological application on five-dimensional teleparallel theory equivalent to general relativity
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作者 Gamal G.L.Nashed 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第10期122-129,共8页
A theory of(4+1)-dimensional gravity has been developed on the basis of which equivalent to the theory of general relativity by teleparallel.The fundamental gravitational field variables are the 5-dimensional(5D)... A theory of(4+1)-dimensional gravity has been developed on the basis of which equivalent to the theory of general relativity by teleparallel.The fundamental gravitational field variables are the 5-dimensional(5D) vector fields(pentad),defined globally on a manifold M,and gravity is attributed to the torsion.The Lagrangian density is quadratic in the torsion tensor.We then apply the field equations to two different homogenous and isotropic geometric structures which give the same line element,i.e.,FRW in five dimensions.The cosmological parameters are calculated and some cosmological problems are discussed. 展开更多
关键词 5D teleparallel equivalent of general relativity 5D solutions cosmological parameters cosmological problems
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Brane world black holes in teleparallel theory equivalent to general relativity and their Killing vectors,energy,momentum and angular momentum
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作者 Gamal G.L.Nashed 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第2期77-91,共15页
The energy--momentum tensor, which is coordinate-independent, is used to calculate energy, momentum and angular momentum of two different tetrad fields. Although, the two tetrad fields reproduce the same space--time t... The energy--momentum tensor, which is coordinate-independent, is used to calculate energy, momentum and angular momentum of two different tetrad fields. Although, the two tetrad fields reproduce the same space--time their energies are different. Therefore, a regularized expression of the gravitational energy--momentum tensor of the teleparallel equivalent of general relativity (TEGR), is used to make the energies of the two tetrad fields equal. The definition of the gravitational energy--momentum is used to investigate the energy within the external event horizon. The components of angular momentum associated with these space--times are calculated. In spite of using a static space--time, we get a non-zero component of angular momentum! Therefore, we derive the Killing vectors associated with these space--times using the definition of the Lie derivative of a second rank tensor in the framework of the TEGR to make the picture more clear. 展开更多
关键词 teleparallel equivalent of general relativity brane world black holes gravitational energy--momentum tensor regularized expression of the gravitational energy--momentum
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A Possible Modification of Einstein's Theory of General Relativity
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作者 QIANShang-Wu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第3期377-380,共4页
This article suggests a new metric theory of gravitation, in which metric field is determined not only by matter and nongravitational field but also by vector graviton field, and in principle there is no need to intro... This article suggests a new metric theory of gravitation, in which metric field is determined not only by matter and nongravitational field but also by vector graviton field, and in principle there is no need to introduce the Einstein's tensor. In order to satisfy automatically the geodesic postulate, an additional coordinate condition is needed. For the spherically symmetric static field, it leads us to quite different conclusions from those of Einstein's general relativity in the interior region of the surface of infinite redshift. Accurate to the first order of , it obtains the same results about the four experimental tests of general relativity. 展开更多
关键词 general relativity metric theory of gravitation vector graviton field
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The mass limit of white dwarfs with strong magnetic fields in general relativity
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作者 文德华 刘荷蕾 张向东 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第8期687-692,共6页
Recently, U. Das and B. Mukhopadhyay proposed that the Chandrasekhar limit of a white dwarf could reach a new high level (2.58M) if a superstrong magnetic field were considered (Das U and Mukhopadhyay B 2013 Phys. ... Recently, U. Das and B. Mukhopadhyay proposed that the Chandrasekhar limit of a white dwarf could reach a new high level (2.58M) if a superstrong magnetic field were considered (Das U and Mukhopadhyay B 2013 Phys. Rev. Lett. 110 071102), where the structure of the strongly magnetized white dwarf (SMWD) is calculated in the framework of Newtonian theory (NT). As the SMWD has a far smaller size, in contrast with the usual expectation, we found that there is an obvious general relativistic effect (GRE) in the SMWD. For example, for the SMWD with a one Landau level system, the super-Chandrasekhar mass limit in general relativity (GR) is approximately 16.5% lower than that in NT. More interestingly, the maximal mass of the white dwarf will be first increased when the magnetic field strength keeps on increasing and reaches the maximal value M = 2.48MQ with BD = 391.5. Then if we further increase the magnetic fields, surprisingly, the maximal mass of the white dwarf will decrease when one takes the GRE into account. 展开更多
关键词 strongly magnetize field white dwarf general relativity effect
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Five-dimensional teleparallel theory equivalent to general relativity,the axially symmetric solution,energy and spatial momentum
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作者 Gamal G.L.Nashed 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第11期102-109,共8页
A theory of (4+1)-dimensional gravity is developed on the basis of the teleparallel theory equivalent to general relativity. The fundamental gravitational field variables are the five-dimensional vector fields (pe... A theory of (4+1)-dimensional gravity is developed on the basis of the teleparallel theory equivalent to general relativity. The fundamental gravitational field variables are the five-dimensional vector fields (pentad), defined globally on a manifold M, and gravity is attributed to the torsion. The Lagrangian density is quadratic in the torsion tensor. We then give the exact five-dimensional solution. The solution is a generalization of the familiar Schwarzschild and Kerr solutions of the four-dimensional teleparallel equivalent of general relativity. We also use the definition of the gravitational energy to calculate the energy and the spatial momentum. 展开更多
关键词 five-dimensional teleparallel equivalent of general relativity five-dimensional solution energy and spatial momentum
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Spherically symmetric solution in higher-dimensional teleparallel equivalent of general relativity
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作者 Gamal G.L.Nashed 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第2期120-127,共8页
A theory of(N+1)-dimensional gravity is developed on the basis of the teleparallel equivalent of general relativity(TEGR).The fundamental gravitational field variables are the(N+1)-dimensional vector fields,de... A theory of(N+1)-dimensional gravity is developed on the basis of the teleparallel equivalent of general relativity(TEGR).The fundamental gravitational field variables are the(N+1)-dimensional vector fields,defined globally on a manifold M,and the gravitational field is attributed to the torsion.The form of Lagrangian density is quadratic in torsion tensor.We then give an exact five-dimensional spherically symmetric solution(Schwarzschild(4+1)-dimensions).Finally,we calculate energy and spatial momentum using gravitational energy-momentum tensor and superpotential 2-form. 展开更多
关键词 (N+1)-dimensional teleparallel equivalent of general relativity five-dimensional solution energy and momentum
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Atomization Theorems in Mathematical Physics and General Relativity
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作者 Sergei Yurievich Eremenko 《Journal of Applied Mathematics and Physics》 2023年第1期158-191,共34页
Formulated Atomization Theorems extend the theory of Atomic AString Functions evolving since the 1970s allowing representation of polynomials, complex analytic functions, and solutions of linear and nonlinear differen... Formulated Atomization Theorems extend the theory of Atomic AString Functions evolving since the 1970s allowing representation of polynomials, complex analytic functions, and solutions of linear and nonlinear differential equations via Atomic Series over smooth finite Atomic Splines. Noting the preservation of analyticity for Ricci and Einstein tensors, special new theorems are formulated for General Relativity representing spacetime field via superpositions of flexible finite “solitonic atoms” resembling quanta. The novel Atomic Spacetime model correlates with A. Einstein’s 1933 paper predicting a new “atomic theory”. The theorems can be applied to many theories of mathematical physics, elasticity, hydrodynamics, soliton, and field theories for unified representation of fields via series over finite Atomic AString Functions which may offer a unified theory under research where fields are connected with a common mathematical ancestor. 展开更多
关键词 Atomic Function AString Splines SERIES SPACETIME general relativity
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Link between Allais Effect and General Relativity’s Residual Arc during Solar Eclipse
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作者 Russell Bagdoo 《Journal of Modern Physics》 2020年第10期1620-1638,共19页
The purpose of this article is to establish a relation between two gravitational anomalies: one that has attracted part of the scientific community, the Allais effect that occurs during solar eclipse;the other, notice... The purpose of this article is to establish a relation between two gravitational anomalies: one that has attracted part of the scientific community, the Allais effect that occurs during solar eclipse;the other, noticed but forgotten by the whole scientific community, the General Relativity’s residual arc of the curvature of rays of light in the solar gravitational field during the same eclipse. There is a systematically observed deflection about 10% larger than the theoretical value of General Relativity, which coincides with the “eclipse effect” found by Maurice Allais, thrown aside because it upsets the established truths. These corresponding anomalies were never explained by any theories and turn out to be new gravitational physics. 展开更多
关键词 Allais Effect Paraconical Pendulum general relativity Eclipse Experience PARALLAX Arc Residue Interferometry
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The Conservation Law and the Radiation of General Relativity
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作者 林汝耀 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第3期223-228,共6页
This paper presents the conservation law of Einstein's General Relativity, in whichthe continuity equation of matter and gravitational field is implicitly derived from theequation of motion of matter. Although the... This paper presents the conservation law of Einstein's General Relativity, in whichthe continuity equation of matter and gravitational field is implicitly derived from theequation of motion of matter. Although the obtained energy-momentum tensor is thesame as the Landau- Lifshitz pseudotensor. the physical and conceptual foundation aredifferent. Two alternative methods to obtain the gravitational radiation are proposed inthis paper as well The radiation will be derived from the equation of motion of matterand geodesic equation separately. 展开更多
关键词 general relativity. equation of motion of matter. geodesicequation
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