scholarly journals Cylindrically Symmetric, Asymptotically Flat, Petrov Type D Spacetime with a Naked Curvature Singularity and Matter Collapse

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Faizuddin Ahmed
Keyword(s):  
Cosmic Time ◽  
Petrov Type ◽  
Energy Conditions ◽  
Anisotropic Fluid ◽  
Curvature Singularity ◽  
Field Equations ◽  
Asymptotically Flat ◽  
Type D ◽  
Cylindrically Symmetric ◽  
Petrov Type D

We present a cylindrically symmetric, Petrov type D, nonexpanding, shear-free, and vorticity-free solution of Einstein’s field equations. The spacetime is asymptotically flat radially and regular everywhere except on the symmetry axis where it possesses a naked curvature singularity. The energy-momentum tensor of the spacetime is that for an anisotropic fluid which satisfies the different energy conditions. This spacetime is used to generate a rotating spacetime which admits closed timelike curves and may represent a Cosmic Time Machine.

Regular cylindrically symmetric Einstein-Maxwell metrics of Petrov type D

1991 ◽  
Vol 8 (1) ◽  
pp. 245-248
Author(s):  
A D Dagotto ◽  
R J Gleiser ◽  
C O Nicasio
Keyword(s):  
Petrov Type ◽  
Type D ◽  
Cylindrically Symmetric ◽  
Petrov Type D

scholarly journals Petrov type D equation on horizons of nontrivial bundle topology

2019 ◽  
Vol 100 (8) ◽  
Author(s):  
Denis Dobkowski-Ryłko ◽  
Jerzy Lewandowski ◽  
István Rácz
Keyword(s):  
Petrov Type ◽  
Type D ◽  
Petrov Type D

Exact wormholes solutions without exotic matter in f(R,T) gravity

2019 ◽  
Vol 16 (03) ◽  
pp. 1950046 ◽  
Author(s):  
M. Zubair ◽  
Rabia Saleem ◽  
Yasir Ahmad ◽  
G. Abbas
Keyword(s):  
Momentum Tensor ◽  
Exotic Matter ◽  
Gravity Models ◽  
Energy Conditions ◽  
Anisotropic Fluid ◽  
Energy Tensor ◽  
Field Equations ◽  
Stress Energy ◽  
Symmetric Geometry ◽  
The Stability

This paper is aimed to evaluate the existence of wormholes in viable [Formula: see text] gravity models (where [Formula: see text] is the scalar curvature and [Formula: see text] is the trace of stress–energy tensor of matter). The exact solutions for energy–momentum tensor components depending on different shapes and redshift functions are calculated without some additional constraints. To investigate this, we consider static spherically symmetric geometry with matter contents as anisotropic fluid and formulate the Einstein field equations for three different [Formula: see text] models. For each model, we derive expression for weak and null energy conditions and graphically analyzed its violation near the throat. It is really interesting that wormhole solutions do not require the presence of exotic matter — like that in general relativity. Finally, the stability of the solutions for each model is presented using equilibrium condition.

scholarly journals Axially Symmetric, Asymptotically Flat Vacuum Metric with a Naked Singularity and Closed Timelike Curves

2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Debojit Sarma ◽  
Faizuddin Ahmed ◽  
Mahadev Patgiri
Keyword(s):  
Naked Singularity ◽  
Empty Space ◽  
Space Time ◽  
Axially Symmetric ◽  
Field Equations ◽  
Closed Timelike Curves ◽  
Asymptotically Flat ◽  
Type D ◽  
Initial Hypersurface ◽  
Petrov Classification

We present an axially symmetric, asymptotically flat empty space solution of the Einstein field equations containing a naked singularity. The space-time is regular everywhere except on the symmetry axis where it possesses a true curvature singularity. The space-time is of type D in the Petrov classification scheme and is locally isometric to the metrics of case IV in the Kinnersley classification of type D vacuum metrics. Additionally, the space-time also shows the evolution of closed timelike curves (CTCs) from an initial hypersurface free from CTCs.

scholarly journals Noether Gauge Symmetries for Petrov Type D-Levi-Civita Space-Time in Spherical and Cylindrical Coordinates

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Adil Jhangeer ◽  
Tayyaba Naz
Keyword(s):  
Space Time ◽  
Petrov Type ◽  
Conserved Quantities ◽  
Restricted Range ◽  
Cylindrical Coordinates ◽  
Type D ◽  
Gauge Symmetries ◽  
Petrov Type D

Petrov Type D-Levi-Civita (DLC) space-time is considered in two different coordinates, that is, spherical and cylindrical. Noether gauge symmetries and their corresponding conserved quantities for respective metric with the restricted range of parameters and coordinates are discussed.

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