Renormalized quantum stress–energy tensor for massive spinor fields around global monopoles

2020 ◽  
Vol 35 (11) ◽  
pp. 2050077
Author(s):  
Owen Pavel Fernández Piedra
Keyword(s):  
Spinor Field ◽  
Energy Conditions ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Spinor Fields ◽  
Characteristic Radius ◽  
Stress Energy ◽  
Massive Spinor ◽  
Global Monopoles ◽  
Tensor Formula

The renormalized quantum stress–energy tensor [Formula: see text] for a massive spinor field around global monopoles is constructed within the framework of Schwinger–DeWitt approximation, valid whenever the Compton length of the quantum field is much less than the characteristic radius of the curvature of the background geometry. The results obtained show that the quantum massive spinor field in the global monopole spacetime violates all the pointwise energy conditions.

scholarly journals Stability of the Regular Hayward Thin-Shell Wormholes

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
M. Sharif ◽  
Saadia Mumtaz
Keyword(s):  
Black Hole ◽  
Thin Shell ◽  
Energy Conditions ◽  
Stability Conditions ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Cosmic Expansion ◽  
Stress Energy ◽  
Thin Shell Wormholes ◽  
The Stability

The aim of this paper is to construct regular Hayward thin-shell wormholes and analyze their stability. We adopt Israel formalism to calculate surface stresses of the shell and check the null and weak energy conditions for the constructed wormholes. It is found that the stress-energy tensor components violate the null and weak energy conditions leading to the presence of exotic matter at the throat. We analyze the attractive and repulsive characteristics of wormholes corresponding toar>0andar<0, respectively. We also explore stability conditions for the existence of traversable thin-shell wormholes with arbitrarily small amount of fluid describing cosmic expansion. We find that the space-time has nonphysical regions which give rise to event horizon for0<a0<2.8and the wormhole becomes nontraversable producing a black hole. The nonphysical region in the wormhole configuration decreases gradually and vanishes for the Hayward parameterl=0.9. It is concluded that the Hayward and Van der Waals quintessence parameters increase the stability of thin-shell wormholes.

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.

scholarly journals CANONICAL AND GRAVITATIONAL STRESS-ENERGY TENSORS

2006 ◽  
Vol 15 (07) ◽  
pp. 959-989 ◽  
Author(s):  
M. LECLERC
Keyword(s):  
General Relativity ◽  
Matter Field ◽  
Field Energy ◽  
Energy Tensor ◽  
Maxwell System ◽  
Stress Energy Tensor ◽  
Spinor Fields ◽  
Gravitational Stress ◽  
Stress Energy ◽  
Matter Fields

We deal with the question, under which circumstances the canonical Noether stress-energy tensor is equivalent to the gravitational (Hilbert) tensor for general matter fields under the influence of gravity. In the framework of general relativity, the full equivalence is established for matter fields that do not couple to the metric derivatives. Spinor fields are included into our analysis by reformulating general relativity in terms of tetrad fields, and the case of Poincaré gauge theory, with an additional, independent Lorentz connection, is also investigated. Special attention is given to the flat limit, focusing on the expressions for the matter field energy (Hamiltonian). The Dirac–Maxwell system is investigated in detail, with special care given to the separation of free (kinetic) and interaction (or potential) energy. Moreover, the stress-energy tensor of the gravitational field itself is briefly discussed.

scholarly journals THE EXTENDED ALGEBRA OF OBSERVABLES FOR DIRAC FIELDS AND THE TRACE ANOMALY OF THEIR STRESS-ENERGY TENSOR

2009 ◽  
Vol 21 (10) ◽  
pp. 1241-1312 ◽  
Author(s):  
CLAUDIO DAPPIAGGI ◽  
THOMAS-PAUL HACK ◽  
NICOLA PINAMONTI
Keyword(s):  
Back Reaction ◽  
Energy Tensor ◽  
Quantum Field ◽  
Stress Energy Tensor ◽  
Covariant Quantum ◽  
Algebra Of Observables ◽  
Spinor Fields ◽  
Trace Anomaly ◽  
Stress Energy ◽  
Dirac Spinors

We discuss from scratch the classical structure of Dirac spinors on an arbitrary globally hyperbolic, Lorentzian spacetime, their formulation as a locally covariant quantum field theory, and the associated notion of a Hadamard state. Eventually, we develop the notion of Wick polynomials for spinor fields, and we employ the latter to construct a covariantly conserved stress-energy tensor suited for back-reaction computations. We shall explicitly calculate its trace anomaly in particular.

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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