排序方式: 共有11条查询结果,搜索用时 31 毫秒
1.
Carlos Kozameh Ezra T. Newman Gilberto Silva-Ortigoza 《General Relativity and Gravitation》2008,40(10):2043-2050
A problem in general relativity is how to extract physical information from solutions to the Einstein equations. Most often
information is found from special conditions, e.g., special vector fields, symmetries or approximate symmetries. Our concern
is with asymptotically flat space–times with approximate symmetry: the BMS group. For these spaces the Bondi four-momentum
vector and its evolution, found at infinity, describes the total energy–momentum and the energy–momentum radiated. By generalizing
the simple idea of the transformation of (electromagnetic) dipoles under a translation, we define (analogous to center of
charge) the center of mass for asymptotically flat Einstein–Maxwell fields. This gives kinematical meaning to the Bondi four-momentum,
i.e., the four-momentum and its evolution which is described in terms of a center of mass position vector, its velocity and
spin-vector. From dynamical arguments, a unique (for our approximation) total angular momentum and evolution equation in the
form of a conservation law is found.
Third Award in the 2008 Essay Competition of the Gravity Research Foundation. 相似文献
2.
Gilberto Silva-Ortigoza 《General Relativity and Gravitation》2001,33(3):395-404
It is shown that each component of the Dirac field satisfies a decoupled equation, which admits separable solutions, when the background spacetime is the Bertotti–Robinson metric, which is a solution of the Einstein vacuum field equations with a cosmological constant. Furthermore, the seperated functions appearing in the solutions are shown to obey identities of the Teukolsky–Starobinsky type and the separable solutions are shown to be eigenfunctions of a certain differential operator. 相似文献
3.
Gilberto Silva-Ortigoza 《General Relativity and Gravitation》2001,33(6):1077-1091
The purpose of this work is to study the structure and nature of the singularities of wavefronts in flat space-time. We computed the behavior at the singularities of important objects that take place in the null surface formulation of general relativity. As a secondary result we show that the Minkowski space-time with non-trivial null surfaces is a solution of the null surface approach to general relativity. 相似文献
4.
5.
G. Silva-Ortigoza 《General Relativity and Gravitation》1998,30(1):45-52
Assuming that the background spacetime is a solution of the Einstein vacuum equations without cosmological constant, we analyze how the Rarita-Schwinger equations can be obtained via a particular generalization of the usual spin-3/2 massless free field equations. On the basis of this analysis we speculate on the possibility of finding other generalizations of the Rarita-Schwinger equations. 相似文献
6.
Carlos Kozameh Ezra T. Newman Raul Ortega Gilberto Silva-Ortigoza 《General Relativity and Gravitation》2009,41(5):1139-1149
We argue that the well-known problem of the instabilities that are associated with the self-forces (radiation reaction forces)
in classical electrodynamics are possibly stabilized by the introduction of gravitational forces via general relativity. 相似文献
7.
Carlos Kozameh Ezra T. Newman Gilberto Silva-Ortigoza 《General Relativity and Gravitation》2006,38(11):1559-1564
We discuss the existence, arising by analogy to that in algebraically special space-times, of a unique asymptotically shear-free
congruence in any asymptotically flat space-time. Associated with it is a unique complex analytic curve in H-space. The surprising
potential physical significance of this curve is discussed.
Fifth Award in the 2006 Essay Competition of the Gravity Research Foundation. 相似文献
8.
9.
In this work we study the quantum system with the symmetric Konwent potential and show how to find its exact solutions. We find that the solutions are given by the confluent Heun function. The eigenvalues have to be calculated numerically because series expansion method does not work due to the variable z ≥ 1. The properties of the wave functions depending on the potential parameter A are illustrated for given potential parameters V_0 and a. The wave functions are shrunk towards the origin with the increasing |A|. In particular, the amplitude of wave function of the second excited state moves towards the origin when the positive parameter A decreases. We notice that the energy levels ε_i increase with the increasing potential parameter |A| ≥ 1, but the variation of the energy levels becomes complicated for |A| ∈(0, 1), which possesses a double well. It is seen that the energy levels ε_i increase with |A| for the parameter interval A ∈(-1, 0), while they decrease with |A| for the parameter interval A ∈(0, 1). 相似文献
10.
G. Silva-Ortigoza 《General Relativity and Gravitation》2000,32(12):2243-2257
In this work we integrate the null geodesic equations in three-dimensional Minkowski space-time in order to obtain the light-cone cut function; that is, the function that describes the intersection, Cx
a, of the light cone from each space-time point, x
a, with future null infinity I
+. Furthermore, using this result, we locate the singularities of the null surface obtained as the envelope of the past light cones from points on a deformed light-cone cut of I
+. 相似文献