scholarly journals Hyperbolically symmetric sources in Palatini f(R) gravity

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
M. Z. Bhatti ◽  
Z. Yousaf ◽  
Z. Tariq
Keyword(s):  
Field Theory ◽  
Analytical Techniques ◽  
Gravitational Theory ◽  
Quantum Field ◽  
The Past ◽  
Structure Scalars ◽  
Algebraic Expressions ◽  
Static Solutions ◽  
Gravitational Equations ◽  
Hilbert Action

AbstractA thorough examination of static hyperbolically symmetric matter configuration in the context of Palatini f(R) gravitational theory has been carried out in this manuscript. Following the work of Herrera et al. (Phys. Rev. D 103: 024037, 2021) we worked out the modified gravitational equations and matching conditions using the Palatini technique of variation in Einstein–Hilbert action. It is found from the evaluations that the energy density along with the contribution of dark source terms is inevitably negative which is quite useful in explaining several quantum field effects, because negative energies are closely linked with the quantum field theory. Such negative energies may also assist in time-travel to the past and formation of artificial wormholes. Furthermore, we evaluated the algebraic expressions for the mass of interior hyperbolical geometry and total energy budget, i.e., the Tolman mass of the considered source. Also, the structure scalars are evaluated to analyze the properties of matter configuration. Few analytical techniques are also presented by considering several cases to exhibit the exact analytical static solutions of the modified gravitational equations.

Introduction to scattering amplitudes

2019 ◽  
pp. 183-204
Author(s):  
David A. Kosower
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Scattering Amplitudes ◽  
Traditional Approach ◽  
Feynman Diagrams ◽  
Quantum Field ◽  
The Past

This chapter covers the new on-shell methods that have been developed over the past twenty years for computing scattering amplitudes in quantum field theory. These methods break free from the traditional approach of Feynman diagrams. The chapter covers a subset of topics, setting up the basic kinematics, spinor helicities, spinor products, and the calculation of tree amplitudes.

Can a Nonsymmetric Metric mimic NCQFT in e+e- → γγ?

2007 ◽  
Vol 22 (07n10) ◽  
pp. 699-709
Author(s):  
Nick Kersting ◽  
Yong-Liang Ma
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Flat Space ◽  
Gravitational Theory ◽  
Quantum Field ◽  
Noncommutative Quantum Field Theory ◽  
Pair Annihilation ◽  
Nonsymmetric Metric ◽  
Noncommutative Quantum ◽  
Gravitational Background

In the nonsymmetric gravitational theory (NGT) the space-time metric gμν departs from the flat-space Minkowski form ημν such that it is no longer symmetric, i.e.gμν ≠ gνμ. We find that in the most conservative such scenario coupled to quantum field theory, which we call Minimally Nonsymmetric Quantum Field Theory (MNQFT), there are experimentally measurable consequences similar to those from noncommutative quantum field theory (NCQFT). This can be expected from the Seiberg-Witten map which has recently been interpreted as equating gauge theories on noncommutative spacetimes with those in a field dependent gravitational background. In particular, in scattering processes such as the pair annihilation e+e- → γγ, both theories make the same striking prediction that the azimuthal cross section oscillates in ϕ. However the predicted number of oscillations differs in the two theories: MNQFT predicts between one and four, whereas NCQFT has no such restriction.

scholarly journals CONSTRAINTS ON EMERGENT GRAVITY

2009 ◽  
Vol 18 (14) ◽  
pp. 2249-2255 ◽  
Author(s):  
ALEJANDRO JENKINS
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
General Relativity ◽  
Gauge Invariance ◽  
Energy Operator ◽  
Gravitational Theory ◽  
Quantum Field ◽  
Principle Of Equivalence ◽  
Stress Energy ◽  
Low Energies

In this essay we review the central difficulty in formulating a viable quantum field theory in which gravity is emergent at low energies rather than being mediated by a fundamental gauge field. The Weinberg–Witten theorem forbids spin 2, massless modes from carrying Lorentz-covariant stress–energy. In general relativity the stress–energy is not covariant because it violates a gauge invariance, but a gravitational theory without fundamental spin 2 gauge invariance must either lack a stress–energy operator or have a nonrelativistic graviton. The latter option is incompatible with the principle of equivalence, though such theories are not necessarily ruled out at low energies.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

A Review of Conformal Field Theory in 2D

2014 ◽  
Vol 6 (2) ◽  
pp. 1079-1105
Author(s):  
Rahul Nigam
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Conformal Field Theory ◽  
Statistical Mechanics ◽  
Critical Behavior ◽  
Verma Module ◽  
Virasoro Algebra ◽  
Quantum Field ◽  
Conformal Field ◽  
Insight Into

In this review we study the elementary structure of Conformal Field Theory in which is a recipe for further studies of critical behavior of various systems in statistical mechanics and quantum field theory. We briefly review CFT in dimensions which plays a prominent role for example in the well-known duality AdS/CFT in string theory where the CFT lives on the AdS boundary. We also describe the mapping of the theory from the cylinder to a complex plane which will help us gain an insight into the process of radial quantization and radial ordering. Finally we will develop the representation of the Virasoro algebra which is the well-known "Verma module".  

Some remarks on a deformed quantum field theory

2002 ◽  
Author(s):  
Marco Aurelio Do Rego Monteiro ◽  
V. B. Bezerra ◽  
E. M.F. Curado
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Quantum Field
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