scholarly journals AdS2×S2 GEOMETRIES AND THE EXTREME QUANTUM-CORRECTED BLACK HOLES

2009 ◽  
Vol 24 (31) ◽  
pp. 2517-2530 ◽  
Author(s):  
JERZY MATYJASEK ◽  
DARIUSZ TRYNIECKI
Keyword(s):  
Order Term ◽  
Second Order ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Field Equations ◽  
Massive Scalar Field ◽  
Stress Energy ◽  
Consistent Solution ◽  
Leading Term ◽  
Horizon Geometry

The second-order term of the approximate stress–energy tensor of the quantized massive scalar field in the Bertotti–Robinson and Reissner–Nordström spacetimes is constructed within the framework of the Schwinger–DeWitt method. It is shown that although the Bertotti–Robinson geometry is a self-consistent solution of the (Λ = 0) semiclassical Einstein field equations with the source term given by the leading term of the renormalized stress–energy tensor, it does not remain so when the next-to-leading term is taken into account and requires the introduction of a cosmological term. The addition of the electric charge to the system does not change this behavior. The near horizon geometry of the extreme quantum-corrected Reissner–Nordström black hole is analyzed. It has the AdS2 ×S2 topology and the sum of the curvature radii of the two-dimensional submanifolds is proportional to the trace of the second-order term. It suggests that the "minimal" approximation should be constructed from the first two terms of the Schwinger–DeWitt expansion

scholarly journals Quaternionic electrodynamics

2020 ◽  
Vol 35 (39) ◽  
pp. 2050327
Author(s):  
Sergio Giardino
Keyword(s):  
Poynting Vector ◽  
Magnetic Monopoles ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Field Equations ◽  
Electrodynamic Force ◽  
Quantization Rule ◽  
Dirac Monopole ◽  
Charge Quantization ◽  
Stress Energy

We develop a quaternionic electrodynamics and show that it naturally supports the existence of magnetic monopoles. We obtained the field equations, the continuity equation, the electrodynamic force law, the Poynting vector, the energy conservation, and the stress-energy tensor. The formalism also enabled us to generalize the Dirac monopole and the charge quantization rule.

Vacuum stress-energy tensor of a massive scalar field in a wormhole spacetime

2010 ◽  
Vol 81 (8) ◽  
Author(s):  
V. B. Bezerra ◽  
E. R. Bezerra de Mello ◽  
N. R. Khusnutdinov ◽  
S. V. Sushkov
Keyword(s):  
Scalar Field ◽  
Energy Tensor ◽  
Massive Scalar ◽  
Stress Energy Tensor ◽  
Massive Scalar Field ◽  
Stress Energy

scholarly journals Wormhole geometries in Eddington-Inspired Born–Infeld gravity

2015 ◽  
Vol 30 (35) ◽  
pp. 1550190 ◽  
Author(s):  
Tiberiu Harko ◽  
Francisco S. N. Lobo ◽  
M. K. Mak ◽  
Sergey V. Sushkov
Keyword(s):  
Exact Solution ◽  
Nonlinear Electrodynamics ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Field Equations ◽  
Asymptotically Flat ◽  
Gravitational Field Equations ◽  
Stress Energy ◽  
Modified Theory Of Gravity ◽  
Modified Theory

Eddington-inspired Born–Infeld (EiBI) gravity is a recently proposed modified theory of gravity, based on the classic work of Eddington and Born–Infeld nonlinear electrodynamics. In this paper, we consider the possibility that wormhole geometries are sustained in EiBI gravity. We present the gravitational field equations for an anisotropic stress–energy tensor and consider the generic conditions, for the auxiliary metric, at the wormhole throat. In addition to this, we obtain an exact solution for an asymptotically flat wormhole.

The stress-energy tensor

2019 ◽  
pp. 59-65
Author(s):  
Steven Carlip
Keyword(s):  
Equations Of Motion ◽  
Scalar Fields ◽  
Gravitational Energy ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Field Equations ◽  
Perfect Fluids ◽  
Stress Energy ◽  
Relationship Of ◽  
The Relationship

The “source” of gravity in the Einstein field equations is the stress-energy tensor. After a discussion of why gravitational mass should be part of a rank two tensor, this chapter derives the stress-energy tensor for a variety of types of matter: point particles, perfect fluids, scalar fields, and electromagnetism. The chapter discusses the relationship of differential and integral conservation laws, and introduces the problem of gravitational energy. It concludes with a discussion of one of the most remarkable results of general relativity, the fact that equations of motion for matter do not need to be introduced separately, but follow from the field equations.

Stability of anisotropic perturbed Einstein universe in f(R,T) theory

2020 ◽  
Vol 35 (27) ◽  
pp. 2050222
Author(s):  
M. Sharif ◽  
Sana Saleem
Keyword(s):  
General Relativity ◽  
State Parameter ◽  
Fluid Distribution ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Field Equations ◽  
Scale Factors ◽  
Stress Energy ◽  
Equation Of State Parameter ◽  
The Stability

The aim of this paper is to investigate the stability of Einstein static cosmos using anisotropic homogeneous perturbations in the background of [Formula: see text] theory in which [Formula: see text] and [Formula: see text] express the Ricci scalar and trace of the stress–energy tensor, respectively. To accomplish this work, we consider perfect fluid distribution and adopt small anisotropic perturbations in the scale factors and matter contents. We develop static and perturbed field equations that are simplified by using equation of state parameter. For the specific models of [Formula: see text] theory with conserved and non-conserved stress–energy tensor, the Einstein solutions are explored and their stability regions are analyzed graphically. We conclude that the static Einstein stable universe with anisotropic perturbations exists in this framework contrary to general relativity.

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