Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userHomogeneous singularities inside collapsing wormholes
263
0
0.0
(
0
)
Added by
Elena Novikova Ph.D.
Publication date
2009
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
We analyze analytically and numerically the origin of the singularity in the course of the collapse of a wormhole with the exotic scalar field Psi with negative energy density, and with this field Psi together with the ordered magnetic field H. We do this under the simplifying assumptions of the spherical symmetry and that in the vicinity of the singularity the solution of the Einstein equations depends only on one coordinate (the homogeneous approximation). In the framework of these assumptions we found the principal difference between the case of the collapse of the ordinary scalar field Phi with the positive energy density together with an ordered magnetic field H and the collapse of the exotic scalar field Psi together with the magnetic field H. The later case is important for the possible astrophysical manifestation of the wormholes.
rate research
Read More
In this paper we study the evolution of wormhole geometries under intrinsic geometric flows. We make evolve numerically the time symmetric foliations of a family of spherically symmetric asymptotically flat wormholes under the Ricci flow and under the RG-2 flow. We use some theorems adapted from the compact case for studying the evolution of different wormhole types, specially those with high curvature zones. Some metrics expand and others contract at the beginning of the flow, however, all metrics pinch-off at certain time. We present a numerical study of the evolution of wormhole singularities in three dimensions extending the theoretical estimations. Finally, we calculate numerically the Hamiltons entropy of the surface and show that it is monotonous through the evolution.
The purpose of this study is to investigate observational features of Brans-Dicke wormholes in a case if they exist in our Universe. The energy flux from accretion onto a Brans-Dicke wormhole and the so-called maximum impact parameter are studied (the last one might allow to observe light sources through a wormhole throat). The computed values were compared with the corresponding ones for GR-wormholes and Schwarzschild black holes. We shown that Brans-Dicke wormholes are quasi-Schwarzschild objects and should differ from GR wormholes by about one order of magnitude in the accretion energy flux.
The models of cyclic universes and cyclic multiverses based on the alternative gravity theories of varying constants are considered.
Wormholes are hypothetical topologically-non-trivial structures of the spacetime. From the theoretical point of view, the possibility of their existence is challenging but cannot be ruled out. This article is a compact and non-exhaustive review of past and current efforts to search for astrophysical wormholes in the Universe.
We study radial perturbations of a wormhole in $R^2$ gravity to determine regions of stability. We also investigate massive and massless particle orbits and tidal forces in this space-time for a radially infalling observer.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
