摘要:

We show how to transform the spherically symmetric vacuum solution to conformal gravity to the flat metric via coordinate and conformal transformations. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301597

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

In recent years, conformal transformations have been used in a variety of gravitational applications, as well as in other fields. The precise form that these transformations take typically depends on the problem at hand. A brief introduction to the topic of conformal symmetry will lead to a framework from which these applications, such as the mapping of Riemannian spaces and self-similarity, can be put into a broader context. The systematic approach presented suggests a new perspective from which conformal symmetry can be studied. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301598

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Regular monopole and dyon solutions to theSU(2)Einstein Yang-Mills equations in asymptotically anti-de Sitter space are discussed. A class of monopole solutions are shown to be stable against spherically symmetric linear perturbations. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301599

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We study the excited states of the Q-balls by performing stationary perturbation on the spherical Q-balls. We find the exact solution of the stationary perturbation of the global Q-ball. For local Q-balls we solve the equations of motion for the perturbative part approximately by using expansion about the coupling constant. Furthermore we comment on the magnetic field generated by the excited states of local Q-balls during the phase transition. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1303048

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The metric for a broad class of spherically symmetric kink spacetimes is considered and the curvature 2-forms are computed. The mass density and principal pressures are obtained by diagonalizing the energy-momentum tensor. An example of a one-kink spacetime with a particularly simple angular term is presented and shown to satisfy the weak and dominant energy conditions but not the strong energy condition. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301600

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We argue that “effective” superluminal travel, potentially caused by the tipping over of light cones in Einstein gravity, is always associated with violations of the null energy condition (NEC). This is most easily seen by working perturbatively around Minkowski spacetime, where we use linearized Einstein gravity to show that the NEC forces the light cones to contract (narrow). Given the NEC, the Shapiro time delay in any weak gravitational field is always a delay relative to the Minkowski background, and never an advance. Furthermore, any object travelling within the lightcones of the weak gravitational field is similarly delayed with respect to the minimum traversal time possible in the background Minkowski geometry. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301601

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301602

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301603

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Two open graphical user interfaces to the computer algebra system GRTensorII are described. Each can be run locally or via the Internet. These provide students and researchers in the area of General Relativity and related fields with advanced truly portable tools that reduce many complex calculations to elementary functions. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1301604

出版商:AIP    

年代:1999

数据来源: AIP