scholarly journals ASYMPTOTICALLY ANTI-DE SITTER SPACETIMES AND THEIR STRESS ENERGY TENSOR

Strings 2000 ◽  
2001 ◽  
Author(s):  
KOSTAS SKENDERIS
Keyword(s):  
Energy Tensor ◽  
De Sitter ◽  
Stress Energy Tensor ◽  
Stress Energy

Stability of ABG thin-shell around a traversable wormhole

2021 ◽  
pp. 2150044
Author(s):  
M. Sharif ◽  
Komal Ashraf
Keyword(s):  
Thin Shell ◽  
Shape Function ◽  
Energy Conditions ◽  
Energy Tensor ◽  
De Sitter ◽  
Stress Energy Tensor ◽  
Regular Black Hole ◽  
Traversable Wormhole ◽  
Stress Energy ◽  
Barotropic Equation

This paper investigates stability of thin-shell developed from the matching of interior traversable wormhole with exterior Ayon–Beato–Garcia–de Sitter regular black hole through cut and paste approach. We employ Israel formalism and Lanczos equations to obtain the components of surface stress-energy tensor at thin-shell. These surface stresses violate null and weak energy conditions that suggest the presence of exotic matter at thin-shell. The surface pressure explains collapse as well as expanding behavior of the developed geometry. We explore stability of the constructed thin-shell through both perturbations along shell radius as well as barotropic equation of state for three appropriate values of the shape function [Formula: see text]. It is concluded that stability of thin-shell depends on the shape function, charge and cosmological constant.

Dark ingredients in one drop

Open Physics ◽  
2011 ◽  
Vol 9 (3) ◽  
Author(s):  
Irina Dymnikova ◽  
Evgeny Galaktionov
Keyword(s):  
Cosmological Term ◽  
Energy Tensor ◽  
De Sitter ◽  
Stress Energy Tensor ◽  
Dark Fluid ◽  
Spatially Inhomogeneous ◽  
Stress Energy ◽  
Gravitational Vacuum ◽  
De Sitter Vacuum ◽  
Unified Description

AbstractA unified description of dark ingredients is realized by a vacuum dark fluid defined by symmetry of its stress-energy tensor and allowed by General Relativity. The symmetry is reduced compared with the maximally symmetric de Sitter vacuum, which makes vacuum dark fluid essentially anisotropic and allows its density and pressure to evolve. It represents distributed vacuum dark energy by a time-evolving and spatially inhomogeneous cosmological term, and vacuum dark matter by gravitational vacuum solitons which are regular gravitationally bound structures without horizons (dark particles or dark stars), with the de Sitter centre (Λδki) in de Sitter space (λδki).

scholarly journals ASYMPTOTICALLY ANTI-DE SITTER SPACETIMES AND THEIR STRESS ENERGY TENSOR

2001 ◽  
Vol 16 (05) ◽  
pp. 740-749 ◽  
Author(s):  
KOSTAS SKENDERIS
Keyword(s):  
Energy Tensor ◽  
Conformal Transformations ◽  
De Sitter ◽  
Stress Energy Tensor ◽  
Gravitational Action ◽  
Gravitational Stress ◽  
Stress Energy ◽  
Infrared Divergences ◽  
Metric Variation ◽  
Odd Dimensions

We consider asymptotically anti-de Sitter spacetimes in general dimensions. We review the origin of infrared divergences in the on-shell gravitational action, and the construction of the renormalized on-shell action by the addition of boundary counterterms. In odd dimensions, the renormalized on-shell action is not invariant under bulk diffeomorphisms that yield conformal transformations in the boundary (holographic Weyl anomaly). We obtain formulae for the gravitational stress energy tensor, defined as the metric variation of the renormalized on-shell action, in terms of coefficients in the asymptotic expansion of the metric near infinity. The stress energy tensor transforms anomalously under bulk diffeomorphisms broken by infrared divergences.

scholarly journals Energy condition in unimodular f(R, T) gravity

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
Fateme Rajabi ◽  
Kourosh Nozari
Keyword(s):  
Power Law ◽  
Energy Condition ◽  
Energy Conditions ◽  
Energy Tensor ◽  
De Sitter ◽  
Stress Energy Tensor ◽  
Modified Gravity Theory ◽  
Stress Energy ◽  
The Stability ◽  
Interesting Alternative

AbstractWe study an interesting alternative of modified gravity theory, namely, the unimodular f(R, T) gravity in which R is the Ricci scalar and T is the trace of the stress–energy tensor. We study the viability of the model by using the energy conditions. We discuss the strong, weak, null and dominant energy conditions in terms of deceleration, jerk and snap parameters. We investigate energy conditions for reconstructed unimodular f(R, T) models and give some constraints on the parametric space of the model. We observe that by setting appropriately free parameters, energy conditions can be satisfied. Furthermore, we study the stability of the solutions in perturbations framework. In this case, we investigate stability conditions for de Sitter and power law solutions and we examine viability of cosmological evolution of these perturbations. The results show that for some values of the input parameters, for which energy conditions are satisfied, de Sitter and power-law solutions may be stable.

scholarly journals Stress-energy tensor correlators from the world-sheet

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Hanno Bertle ◽  
Andrea Dei ◽  
Matthias R. Gaberdiel
Keyword(s):  
Vertex Operator ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
World Sheet ◽  
Stress Energy ◽  
The World

Abstract The large N limit of symmetric orbifold theories was recently argued to have an AdS/CFT dual world-sheet description in terms of an sl(2, ℝ) WZW model. In previous work the world-sheet state corresponding to the symmetric orbifold stress-energy tensor was identified. We calculate certain 2- and 3-point functions of the corresponding vertex operator on the world-sheet, and demonstrate that these amplitudes reproduce exactly what one expects from the dual symmetric orbifold perspective.

ON THE ELECTROMAGNETIC PERTURBATIONS OF A MULTICONICAL SPACETIME

1996 ◽  
Vol 11 (27) ◽  
pp. 2171-2177
Author(s):  
A.N. ALIEV
Keyword(s):  
Cosmic Strings ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Stress Energy ◽  
Electromagnetic Perturbations

The electromagnetic perturbations propagating in the multiconical spacetime of N parallel cosmic strings are described. The expression for vacuum average of the stress-energy tensor is reduced to a form involving only zero-spin-weighted perturbation modes.

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