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Conformal Ricci Collineations of Static Spherically Symmetric Spacetimes
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作者 Ugur Camci Asghar Qadir K.Saifullah 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第6期1527-1532,共6页
Conformal Ricei collineations of static spherically symmetric spacetimes are studied. The general form of the vector fields generating eonformal Rieei eollineations is found when the Rieei tensor is non-degenerate, in... Conformal Ricei collineations of static spherically symmetric spacetimes are studied. The general form of the vector fields generating eonformal Rieei eollineations is found when the Rieei tensor is non-degenerate, in which ease the number of independent eonformal Rieei eollineations is 15, the maximum number for four-dimensional manifolds. In the degenerate ease it is found that the static spherically symmetric spaeetimes always have an infinite number of eonformal Rieei eollineations. Some examples are provided which admit non-trivial eonformal Rieei eollineations, and perfect fluid source of the matter. 展开更多
关键词 Ricci collineations conformal collineations static spherically symmetric spacetimes
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E-Infinity Dualities, Discontinuous Spacetimes, Xonic Quantum Physics and the Decisive Experiment 被引量:2
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作者 Jean-Paul Auffray 《Journal of Modern Physics》 2014年第15期1427-1436,共10页
Using powerful concepts and tools borrowed from the seminal arsenal connecting physics fundamentals with esoteric set theoretical operations developed in recent years by Alexandria E-infinity theoretician M. S. El Nas... Using powerful concepts and tools borrowed from the seminal arsenal connecting physics fundamentals with esoteric set theoretical operations developed in recent years by Alexandria E-infinity theoretician M. S. El Naschie, this paper explores the deep implications of some of the dualities Dr El Naschie has identified and analyzed in his exposes, connecting them with our own Xonic Quantum Physics (XQP) which places dynamical action rather than spacetime and energy at the core of the System of the World. 展开更多
关键词 E-INFINITY El Naschie Space Time SPACETIME Topology CANTOR Sets Energy Xon Xonic Quantum Physics PLANCK Scale Dirac Electron
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Causal Stability Conditions for General Relativistic Spacetimes
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作者 Ecaterina Marion Howard 《Journal of Physical Science and Application》 2012年第7期258-264,共7页
A brief overview of some open questions in general relativity with important consequences for causality theory is presented, aiming to a better understanding of the causal structure of the spacetime. Special attention... A brief overview of some open questions in general relativity with important consequences for causality theory is presented, aiming to a better understanding of the causal structure of the spacetime. Special attention is accorded to the problem of fundamental causal stability conditions. Several questions are raised and some of the potential consequences of recent results regarding the causality problem in general relativity are presented. A key question is whether causality violating regions are locally allowed. The new concept of almost stable causality is introduced; meanwhile, related conditions and criteria for the stability and almost stability of the causal structure are discussed. 展开更多
关键词 Causality general relativity causal hierarchy causal stability spacetime topology global hyperbolicity chronology.
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Nonexistence of Majorana fermions in Kerr-Newman type spacetimes with nontrivial charge
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作者 He-Qun Zhang Xiao Zhang 《Chinese Physics C》 SCIE CAS CSCD 2024年第11期156-161,共6页
We show that the Dirac equation is separated into four differential equations for time-periodic Majorana fermions in Kerr-Newman and Kerr-Newman-(A)dS spacetimes.Although they cannot be transformed into radial and ang... We show that the Dirac equation is separated into four differential equations for time-periodic Majorana fermions in Kerr-Newman and Kerr-Newman-(A)dS spacetimes.Although they cannot be transformed into radial and angular equations,the four differential equations yield two algebraic identities.When the electric or magnetic charge is nonzero,they conclude that there is no differentiable time-periodic Majorana fermions outside the event horizon in Kerr-Newman and Kerr-Newman-AdS spacetimes,or between the event horizon and the cosmological horizon in Kerr-Newman-dS spacetime. 展开更多
关键词 Dirac equation Majorana fermion Kerr-Newman-type spacetime
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On Light-Like Extremal Surfaces in Curved Spacetimes
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作者 HUANG Shou-Jun HE Chun-Lei 《Communications in Theoretical Physics》 SCIE CAS CSCD 2014年第1期15-22,共8页
In this paper, we find that under a diffeomorphic of nonlinear geodesic equations are concerned with light-like extremal surfaces in curved spaeetimes. It is interesting to transformation of variables, the light-like ... In this paper, we find that under a diffeomorphic of nonlinear geodesic equations are concerned with light-like extremal surfaces in curved spaeetimes. It is interesting to transformation of variables, the light-like extremal surfaces can be described by a system Particularly, we investigate the light-like extremal surfaces in Schwarzschild spacetime in detail and some new special solutions are derived systematically with aim to compare with the known results and to illustrate the method. 展开更多
关键词 light-like extremal surfaces geodesic equations curved spacetimes Schwarzschild spacetime
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Classification of Variational Conservation Laws of General Plane Symmetric Spacetimes
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作者 Usamah S.Al-Ali Ashfaque H.Bokhari +1 位作者 A.H.Kara Ghulam Shabbir 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第9期335-341,共7页
In this article we discuss Noether conservation laws admitted by a Lagrangian L = gab(dx^a/ds)(dx^b/ds)of a test particle moving in the field of a general plane symmetric non-static spacetime metric. In this context, ... In this article we discuss Noether conservation laws admitted by a Lagrangian L = gab(dx^a/ds)(dx^b/ds)of a test particle moving in the field of a general plane symmetric non-static spacetime metric. In this context, we first present a general solution representing a Noether symmetry vector subject to differential constraints satisfied by the general plane symmetric non-static metric. We then use a class of plane symmetric non-static metrics obtained by Feroze et al. and discuss, in each case, Noether conservation laws in comparison with Killing symmetries. 展开更多
关键词 conservation laws Noether symmetries plane symmetric spacetimes
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A massless scalar field in Robertson-Walker spacetimes:Adiabatic regularization and Green’s function
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作者 Yang Zhang Bo Wang Xuan Ye 《Chinese Physics C》 SCIE CAS CSCD 2020年第9期194-209,共16页
We study adiabatic regularization of a coupling massless scalar field in general spatially flat Robertson-Walker(RW)spacetimes.For the conformal coupling,the 2nd-order regularized power spectrum and 4th-order regulari... We study adiabatic regularization of a coupling massless scalar field in general spatially flat Robertson-Walker(RW)spacetimes.For the conformal coupling,the 2nd-order regularized power spectrum and 4th-order regularized stress tensor are zero,and no trace anomaly exists in general RW spacetimes.This is a new result that exceeds those found in de Sitter space.For the minimal coupling,the regularized spectra are also zero in the radiationdominant and matter-dominant stages,as well as in de Sitter space.The vanishing of these adiabatically regularized spectra is further confirmed by direct regularization of the Green's function.For a general coupling and general RW spacetimes,the regularized spectra can be negative under the conventional prescription.At a higher order of regularization,the spectra will generally become positive,but will also acquire IR divergence,which is inevitable for a massless field.To avoid the IR divergence,the inside-horizon regularization is applied.Through these procedures,nonnegative UV-and IR-convergent power spectrum and spectral energy density will eventually be achieved. 展开更多
关键词 quantum fields in curved spacetimes inflationary universe mathematical and relativistic aspects of cosmology
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Positive energy theorem for(4+1)-dimensional asymptotically anti-de Sitter spacetimes
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作者 WANG YaoHua XU Xu 《Science China Mathematics》 SCIE 2014年第2期389-396,共8页
We define the total energy-momenta for(4+1)-dimensional asymptotically anti-de Sitter spacetimes,which comes from the boundary terms at infinity in the integral form of the Weitzenbck formula.Then we prove the positiv... We define the total energy-momenta for(4+1)-dimensional asymptotically anti-de Sitter spacetimes,which comes from the boundary terms at infinity in the integral form of the Weitzenbck formula.Then we prove the positive energy theorem for such spacetimes,following Witten’s original argumentsfor the positive energy theorem in asymptotically flat spacetimes. 展开更多
关键词 positive energy theorem asymptotically anti-de Sitter spacetimes
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Multiverse/Hyperverse Models: (4 + 1)-Dimensional Landscape (Black Saturns, Bousso-Hawking Nucleation, Gogberashvili Multiverses, Schwarzschild-De Sitter Nurseries) and a (3 + 1)-Dimensional Model for Dark Energy
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作者 Igor Yu. Potemine Werner Krause 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第4期1866-1877,共12页
We consider the Hyperverse as a collection of multiverses in a (4 + 1)-dimensional spacetime with gravitational constant G. Multiverses in our model are bouquets of thin shells (with synchronized intrinsic times). If ... We consider the Hyperverse as a collection of multiverses in a (4 + 1)-dimensional spacetime with gravitational constant G. Multiverses in our model are bouquets of thin shells (with synchronized intrinsic times). If gis the gravitational constant of a shell Sand εits thickness, then G~εg. The physical universe is supposed to be one of those thin shells inside the local bouquet called Local Multiverse. Other remarkable objects of the Hyperverse are supposed to be black holes, black lenses, black rings and (generalized) Black Saturns. In addition, Schwarzschild-de Sitter multiversal nurseries can be hidden inside those Black Saturns, leading to their Bousso-Hawking nucleation. It also suggests that black holes in our physical universe might harbor embedded (2 + 1)-dimensional multiverses. This is compatible with outstanding ideas and results of Bekenstein, Hawking-Vaz and Corda about “black holes as atoms” and the condensation of matter on “apparent horizons”. It allows us to formulate conjecture 12.1 about the origin of the Local Multiverse. As an alternative model, we examine spacetime warping of our universe by external universes. It gives data for the accelerated expansion and the cosmological constant Λ, which are in agreement with observation, thus opening a possibility for verification of the multiverse model. 展开更多
关键词 5-Dimensional Gravity Black Hole Black Saturn Cosmological Constant Dark Energy MULTIVERSE Spacetime Warping Thin Shell
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On the Possible Structures of Electron and Proton
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作者 Wei-Xing Xu 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第4期1734-1742,共9页
In this work, the possible structures of electron and proton have been explored. Based on the potential expressions of electron and proton, we found that the electron and proton share the similar structure inside re a... In this work, the possible structures of electron and proton have been explored. Based on the potential expressions of electron and proton, we found that the electron and proton share the similar structure inside re and rn. And within re and rn, the conventional charge concept stops working, the same charge repelling force doesn’t exist anymore and as a result, the requirement of charge conservation is automatically removed. Whereas beyond re and rn, the potential expressions of electron and proton obey the point charge potentials as we normally understand. Therefore, the conventional charge concept can be applied and the requirement of charge conservation takes effect. Furthermore, a possible mechanism for the creations of electric monopole and magnetic monopole is discussed. In addition, to compare the particle size in micro-world, the balloon criterion is proposed. By this balloon criterion, the proton is determined about 10 times bigger than electron. From the physical picture about electron and proton described above, the stabilities of electron and proton can be explained quite well. 展开更多
关键词 Electromagnetic Spacetime Quantum Mechanics ELECTRON PROTON Standard Model Particle Physics “Yin-Yang” Philosophy Electric Monopole Magnetic Monopole Charge Conservation
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Gravitational Waves Background, as Well as Some UFO, FRB and Supernova Flares, Are Due to Compressibility of the Spacetime (CoST)
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作者 Evgeny A. Novikov 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第1期67-70,共4页
The recently observed gravitational wave background is explained in terms of the quantum modification of the general relativity (Qmoger). Some UFO, FRB and supernova flares also can be explained in terms of Qmoger.
关键词 Gravitational Wave Background Quantum Modification of the General Relativity Compressibility of the Spacetime (CoST)
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The Unified Field
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作者 Joseph H. (Cass) Forrington 《Journal of Modern Physics》 2024年第7期1010-1035,共26页
This is a Unified Field description based on the holographic Time Dilation Cosmology, TDC, model, which is an eternal continuum evolving forward in the forward direction of time, at the speed of light, c, at an invari... This is a Unified Field description based on the holographic Time Dilation Cosmology, TDC, model, which is an eternal continuum evolving forward in the forward direction of time, at the speed of light, c, at an invariant 1 s/s rate of time. This is the Fundamental Direction of Evolution, FDE. There is also an evolution down time dilation gradients, the Gravitational Direction of Evolution, GDE. These evolutions are gravity, which is the evolutionary force in time. Gravitational velocities are compensation for the difference in the rate of time, dRt, in a dilation field, and the dRtis equal to the compensatory velocity’s percentage of c, and is a measure of the force in time inducing the velocity. In applied force induced velocities, the dRt is a measure of the resistance in time to the induced velocity, which might be called “anti-gravity” or “negative gravity”. The two effects keep the continuum uniformly evolving forward at c. It is demonstrated that gravity is already a part of the electromagnetic field equations in way of the dRt element contained in the TDC velocity formula. Einstein’s energy formula is defined as a velocity formula and a modified version is used for charged elementary particle solutions. A time dilation-based derivation of the Lorentz force ties gravity directly to the electromagnetic field proving the unified field of gravity and the EMF. It is noted how we could possibly create gravity drives. This is followed by a discussion of black holes, proving supermassive objects, like massive black hole singularities, are impossible, and that black holes are massless Magnetospheric Eternally Collapsing Objects (MECOs) that are vortices in spacetime. . 展开更多
关键词 Unified Field GRAVITY Anti-Gravity Astrophysics Einstein General Relativity Special Relativity Galactic Rotation Velocities Time Dilation SPACETIME Space Time Spacetime Continuum Quantum Continuum MECO Black Hole Event Horizon Timelike Spacelike Lightlike
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Theory and Properties of Atomic Spacetime
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作者 Sergei Yu. Eremenko 《Journal of Applied Mathematics and Physics》 2024年第6期1967-2006,共40页
Following A. Einsteins aspirations for an atomic theory, a novel theory of spacetime quantization/atomization based on finite Atomic AString Functions evolving since the 1970s is offered. Atomization Theorems allow re... Following A. Einsteins aspirations for an atomic theory, a novel theory of spacetime quantization/atomization based on finite Atomic AString Functions evolving since the 1970s is offered. Atomization Theorems allow representing polynomials, analytic functions, and solutions of General Relativity via the superposition of solitonic atoms which can be associated with flexible spacetime quanta, metriants, or elementary distortions. With multiple interpretations discussed, discrete-continuous spacetime is conceptualized as a lattice network of flexible solitonic atoms adjusting locations to reproduce different metrics. The theory may offer some variants of unified field theory under research based on Atomic AString Function where, like in string theory, fields become interconnected having a common mathematical ancestor. 展开更多
关键词 SPACETIME QUANTUM Atomic Function AString SOLITON Metriant Unified Theory
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Dynamic Spacetime: Key to the Mysteries of Dark Matter and Dark Energy
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作者 Tianxi Zhang 《Journal of Modern Physics》 2024年第4期416-434,共19页
Physics is a branch of science to study matter and its motion in space and time. Development of physics usually upgrades human perspective and understanding of the space and time. Einstein successfully developed speci... Physics is a branch of science to study matter and its motion in space and time. Development of physics usually upgrades human perspective and understanding of the space and time. Einstein successfully developed special and general theories of relativity and creatively promoted our perspective of spacetime from Newton’s absolute space and time to his relative spacetime. Based on redshift and distance measurements of galaxies and distant type Ia supernovae, cosmologists have suggested that our universe is expanding at an ever-increasing rate driven by a mysterious dark energy. Recently, the author has proposed that spacetime is dynamic. Spacetime is said to be absolute if it is independent of matter and motion, relative if it is affected by matter and motion, and dynamic if it mutually interacts with matter and motion. In dynamic spacetime, not only do matter and motion distort spacetime, but they are also affected by the distorted spacetime. Spacetime to be dynamic is a consequence of a deep insight to Mach’s principle, which tells us that the inertia of an object results from the gravitational interaction by the rest of the universe. Reaction of dynamic spacetime on a traveling light causes light redshift. Reaction of dynamic spacetime on a fast moving neutrino slows down the neutrino. The derived redshift-distance relation perfectly explained the measurements of distant type Ia supernovae and gamma ray bursts (GRBs) and also naturally obtained Hubble’s law as an approximate relation at small redshift. This explanation of cosmological redshift as the opposition of dynamic spacetime does not mandate the universe to be expanding and accelerating, so that it does not need the universe to be initiated from a Big Bang and driven out mainly by a mysterious dark energy. Extremely slowed down neutrinos in dynamic spacetime, when they are gravitationally trapped around clusters, galaxies, and any celestial objects, would play the role of dark matter in explaining the velocity-radius relations of galaxy’s or cluster’s rotations. 展开更多
关键词 SPACETIME Cosmology REDSHIFT NEUTRINO GRAVITATION Dark Matter Dark Energy
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The Essence of Gravity Is the Expansion Tendency of the Universe after the Big Bang
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作者 Weihong Qian 《Journal of Modern Physics》 2024年第6期804-849,共46页
Why cannot Newton’s theory of gravitation be used to describe the motion of micro particles? This article summarizes and clarifies that Newton’s theory of gravitation is subjectively a statistical description for na... Why cannot Newton’s theory of gravitation be used to describe the motion of micro particles? This article summarizes and clarifies that Newton’s theory of gravitation is subjectively a statistical description for natural phenomena, while its essence is the expansion tendency of particles in the new universe formed after the orthogonal collision (the Big Bang) of objects in the old universe. The new particles formed by the Big Bang exhibit the accelerating expansion and local convergence in the spacetime of the new universe. The force of the accelerating expansion for the new particles comes from the shear stress produced by the orthogonal collision. There is only a one-way conversion from the mass in the old universe to the energy in the new universe without any exchange of information between them. Orthogonal collision forms maximum energy density and accelerates motion of new particles. The theory that orthogonal collision produces a new universe can be used to explain the phenomena of three scales. On the cosmic scale, it can explain the Big Bang, the early celestial formation, and their movements. On the macro scale, it can explain the early Earth’s surface mountain uplift and current atmospheric vortices. At the micro scale, it can explain aurora and other astronomical optical phenomena as well as the generation of new particles. The idea of orthogonal collision attempts to use shear stress and particle potential energy to find a theory of everything that can fully explain all aspects of the universe. 展开更多
关键词 UNIVERSE SPACETIME GRAVITATION Orthogonal Collision Shear Stress Potential Energy
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Gravitational Collapse of Radiating Dyon Solution and Cosmic Censorship Hypothesis 被引量:1
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作者 K. D. Patil S. S. Zade A. N. Mohod 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第3期854-857,共4页
We investigate the possibility of cosmic censorship violation in the gravitational collapse of radiating dyon solution. It is shown that the final outcome of the collapse depends sensitively on the electric and magnet... We investigate the possibility of cosmic censorship violation in the gravitational collapse of radiating dyon solution. It is shown that the final outcome of the collapse depends sensitively on the electric and magnetic charge parameters. The graphs of the outer apparent horizon, inner Cauchy horizon for different values of parameters are drawn. It is found that the electric and magnetic components push the apparent horizon towards the retarded time-coordinate axis, which in turn reduces the radius of the apparent horizon in Valdya spacetime. Also, we extend the earlier work of Chamorro and Virbhadra [Pramana, J. Phys. 45 (1995) 181]. 展开更多
关键词 NAKED SINGULARITIES VAIDYA spacetimes DUST COLLAPSE FLUID TIME STRENGTHS
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Novel Bianchi VII Space Times and Their Properties 被引量:1
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作者 Manavendra Mahato Ajay Pratap Singh 《Journal of Modern Physics》 2016年第5期445-457,共13页
We construct and investigate non conformal anisotropic Bianchi type VII<sub>0</sub> solutions in 5 dimensions. The solutions are asymptotically flat with a singularity. We also construct anisotropic soluti... We construct and investigate non conformal anisotropic Bianchi type VII<sub>0</sub> solutions in 5 dimensions. The solutions are asymptotically flat with a singularity. We also construct anisotropic solutions of Einstein-Maxwell gravity using a procedure similar to Majumdar-Papapetrou solutions with various profiles of charged dust and explore ways to hide the singularity behind the horizon. We further embed it in one higher dimension to get an asymptotically anti de Sitter space and approximate two point correlator of operators with higher conformal dimensions by calculating geodesic lengths. We find a peculiar power law decay of the correlator as a function of separation. 展开更多
关键词 Bianchi spacetimes Anisotropic Spacetime Gauge/Gravity Correspondence
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Thermodynamic Interpretation of Field Equations at Horizon of BTZ Black Hole
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作者 M. Akbar 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第5期1158-1161,共4页
A spacetime horizon comprising with a black hole singularity acts like a boundary of a thermal system associated with the notions of temperature and entropy. In the case of static metric of Banados-Teitelboim-Zanelli ... A spacetime horizon comprising with a black hole singularity acts like a boundary of a thermal system associated with the notions of temperature and entropy. In the case of static metric of Banados-Teitelboim-Zanelli (BTZ) black hole, the field equations near the horizon boundary can be expressed as a thermal identity dE = TdS+ Pr dA, where E = M is the mass of BTZ black hole, dA is the change in the area of the black hole horizon when the horizon is displaced infinitesimally small, Pr is the radial pressure provided by the source of Einstein equations, S = 41πa is the entropy and T =κ/2π is the Hawking temperature associated with the horizon. This approach is studied further to generalize it for non-static BTZ black hole, showing that it is also possible to interpret the field equation near horizon as a thermodynamic identity dE = TdS + PrdA +Ω+dJ, where Ω+ is the angular velocity and J is the angular momentum of BTZ black hole. These results indicate that the field equations for BTZ black hole possess intrinsic thermodynamic properties near the horizon. 展开更多
关键词 SITTER spacetimes 1ST LAW GRAVITY ENTROPY
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Non-Spherical Gravitational Collapse of Strange Quark Matter
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作者 Zade S S Patil K D Mulkalwar P N 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第5期1568-1570,共3页
We study the non-spherical gravitational collapse of the strange quark null fluid. The interesting feature which emerges is that the non-spherical collapse of charged strange quark matter leads to a naked singularity ... We study the non-spherical gravitational collapse of the strange quark null fluid. The interesting feature which emerges is that the non-spherical collapse of charged strange quark matter leads to a naked singularity whereas the gravitational collapse of neutral quark matter proceeds to form a black hole. We extend the earlier work of Harko and Cheng [Phys. Lett. A 266 (2000) 249] to the non-spherical case. 展开更多
关键词 NAKED SINGULARITIES COSMIC CENSORSHIP spacetimes
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Conserved charges of Kerr-Ads spacetime using Poincaré gauge version
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作者 Gamal G. L. Nashed 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第12期96-103,共8页
The process of covariant conserved charge of gravitational theory, which is covariant under general coordinate and local Lorentz transformations, has been applied to many tetrad fields, which reproduce Kerr-Ads spacet... The process of covariant conserved charge of gravitational theory, which is covariant under general coordinate and local Lorentz transformations, has been applied to many tetrad fields, which reproduce Kerr-Ads spacetime, to calculate their conserved charges. It is shown that this process gives an infinite value of the conserved charges for Kerr–Ads spacetime. Therefore, the method of “regularization through relocalization”, i.e., modification of the Lagrangian of the gravitational field through a total derivative, is used. This method gaves a finite and a consistent result of total energy and angular momentum for Kerr–Ads spacetime. 展开更多
关键词 Kerr–Ads spacetimes total conserved charges Poincaré gauge version
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