scholarly journals Gravitational Paramagnetism, Diamagnetism and Gravitational Superconductivity

1996 ◽  
Vol 49 (6) ◽  
pp. 1063 ◽  
Author(s):  
M Agop ◽  
C Gh Buzea ◽  
V Griga ◽  
C Ciubotariu ◽  
C Buzea ◽  
...  
Keyword(s):  
Gravitational Field ◽  
Meissner Effect ◽  
Field Approximation ◽  
Weak Field ◽  
Gauge Model ◽  
Closed Geodesics ◽  
Field Equations ◽  
Gravitational Field Equations ◽  
Weak Field Approximation ◽  
Superconducting Parameters

In the weak field approximation to the gravitational field equations, we study gravitational paramagnetism and diamagnetism, the gravitational Meissner effect and gravitational superconductivity. The spontaneous symmetry breaking corresponds to crossing from closed geodesics to open ones, and to the existence of a critical temperature in the frame of a gauge model at finite temperature. In this later case one can obtain expressions giving the dependence of several superconducting parameters on temperature.

scholarly journals Massive Conformal Gravity

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
F. F. Faria
Keyword(s):  
Scalar Field ◽  
Field Approximation ◽  
Weak Field ◽  
Vacuum Field ◽  
Conformal Transformations ◽  
Conformal Gravity ◽  
Field Equations ◽  
Metric Tensor ◽  
Weak Field Approximation ◽  
Massive Theory

We construct a massive theory of gravity that is invariant under conformal transformations. The massive action of the theory depends on the metric tensor and a scalar field, which are considered the only field variables. We find the vacuum field equations of the theory and analyze its weak-field approximation and Newtonian limit.

scholarly journals HEURISTIC APPROACH TO THE SCHWARZSCHILD GEOMETRY

2005 ◽  
Vol 14 (12) ◽  
pp. 2051-2067 ◽  
Author(s):  
MATT VISSER
Keyword(s):  
Field Approximation ◽  
Weak Field ◽  
Point Particle ◽  
De Sitter ◽  
Field Equations ◽  
Kerr Geometry ◽  
Spacetime Geometry ◽  
Schwarzschild Geometry ◽  
Inertial Frames ◽  
Weak Field Approximation

In this article I present a simple Newtonian heuristic for motivating a weak-field approximation for the spacetime geometry of a point particle. The heuristic is based on Newtonian gravity, the notion of local inertial frames (the Einstein equivalence principle), plus the use of Galilean coordinate transformations to connect the freely falling local inertial frames back to the "fixed stars." Because of the heuristic and quasi-Newtonian manner in which the specific choice of spacetime geometry is motivated, we are at best justified in expecting it to be a weak-field approximation to the true spacetime geometry. However, in the case of a spherically symmetric point mass the result is coincidentally an exact solution of the full vacuum Einstein field equations — it is the Schwarzschild geometry in Painlevé–Gullstrand coordinates. This result is much stronger than the well-known result of Michell and Laplace whereby a Newtonian argument correctly estimates the value of the Schwarzschild radius — using the heuristic presented in this article one obtains the entire Schwarzschild geometry. The heuristic also gives sensible results — a Riemann flat geometry — when applied to a constant gravitational field. Furthermore, a subtle extension of the heuristic correctly reproduces the Reissner–Nordström geometry and even the de Sitter geometry. Unfortunately the heuristic construction is not truly generic. For instance, it is incapable of generating the Kerr geometry or anti-de Sitter space. Despite this limitation, the heuristic does have useful pedagogical value in that it provides a simple and direct plausibility argument (not a derivation) for the Schwarzschild geometry — suitable for classroom use in situations where the full power and technical machinery of general relativity might be inappropriate. The extended heuristic provides more challenging problems — suitable for use at the graduate level.

scholarly journals Quasi-uniform gravitational field of a disk revisited

2019 ◽  
Vol 34 (33) ◽  
pp. 1950228
Author(s):  
Alexander J. Silenko ◽  
Yury A. Tsalkou
Keyword(s):  
Gravitational Field ◽  
Equivalence Principle ◽  
Equations Of Motion ◽  
Field Approximation ◽  
Weak Field ◽  
Riemann Tensor ◽  
Weak Field Approximation

We calculate the quasi-uniform gravitational field of a disk in the weak-field approximation and demonstrate an inappropriateness of preceding results. The Riemann tensor of this field is determined. The nonexistence of the uniform gravitational field is proven without the use of the weak-field approximation. The previously found difference between equations of motion for the momentum and spin in the accelerated frame and in the quasi-uniform gravitational field also takes place for the disk. However, it does not violate the Einstein equivalence principle because of the nonexistence of the uniform gravitational field.

scholarly journals An Experiment to Test the Gravitational Aharonov-Bohm Effect

1994 ◽  
Vol 47 (3) ◽  
pp. 245 ◽  
Author(s):  
Vu B Ho ◽  
Michael J Morgan
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Quantum Interference ◽  
Field Approximation ◽  
Weak Field ◽  
Matter Wave ◽  
Interference Effects ◽  
Weak Field Approximation ◽  
Bohm Effect ◽  
Aharonov Bohm

The gravitational Aharonov-Bohm (AB) effect is examined in the weak-field approximation to general relativity. In analogy with the electromagnetic AB effect, we find that a gravitoelectromagnetic 4-vector potential gives rise to interference effects. A matter wave interferometry experiment, based on a modification of the gravity-induced quantum interference experiment of Colella, Overhauser and Werner (COW), is proposed to explicitly test the gravitoelectric version of the AB effect in a uniform gravitational field.

scholarly journals GRAVITATIONAL FIELD OF A GLOBAL MONOPOLE IN A MODIFIED GRAVITY

2011 ◽  
Vol 03 ◽  
pp. 446-454 ◽  
Author(s):  
T. R. P. CARAMÊS ◽  
E. R. BEZERRA DE MELLO ◽  
M. E. X. GUIMARÃES
Keyword(s):  
Gravitational Field ◽  
Modified Gravity ◽  
Field Approximation ◽  
Weak Field ◽  
Symmetric System ◽  
Radial Coordinate ◽  
Spherically Symmetric ◽  
Global Monopole ◽  
Field Equations ◽  
Metric Tensor

In this paper we analyze the gravitational field of a global monopole in the context of f(R) gravity. More precisely, we show that the field equations obtained are expressed in terms of [Formula: see text]. Since we are dealing with a spherically symmetric system, we assume that F(R) is a function of the radial coordinate only. Moreover, adopting the weak field approximation, we can provide all components of the metric tensor. A comparison with the corresponding results obtained in General Relativity and in the Brans-Dicke theory is also made.

GRAVITATIONAL FIELD OF STATIC THIN PLANAR WALLS IN WEAK-FIELD APPROXIMATION

2003 ◽  
Vol 12 (08) ◽  
pp. 1385-1397 ◽  
Author(s):  
L. CAMPANELLI ◽  
P. CEA ◽  
G. L. FOGLI ◽  
L. TEDESCO
Keyword(s):  
Gravitational Field ◽  
Field Approximation ◽  
Weak Field ◽  
Einstein’S Equations ◽  
Einstein's Equations ◽  
Weak Field Approximation ◽  
Planar Wall

We investigate gravitational properties of thin planar wall solutions of the Einstein's equations in the weak field approximation. We find the general metric solutions and discuss the behavior of a particle placed initially at rest to one side of the plane. Moreover we study the case of non-reflection-symmetric solutions.

scholarly journals CAN A NONLOCAL MODEL OF GRAVITY REPRODUCE DARK MATTER EFFECTS IN AGREEMENT WITH MOND?

2014 ◽  
Vol 23 (01) ◽  
pp. 1450008 ◽  
Author(s):  
IVAN ARRAUT
Keyword(s):  
Dark Matter ◽  
Cosmological Constant ◽  
Field Approximation ◽  
Weak Field ◽  
Nonlocal Model ◽  
Field Equations ◽  
Matter Effects ◽  
Weak Field Approximation

I analyze the possibility of reproducing MONDian dark matter effects by using a nonlocal model of gravity. The model was used before in order to recreate screening effects for the cosmological constant (Λ) value. Although the model in the weak-field approximation (in static coordinates) can reproduce the field equations in agreement with the AQUAL Lagrangian, the solutions are scale dependent and cannot reproduce the same dynamics in agreement with MOND.

Gravitational waves

2019 ◽  
pp. 72-79
Author(s):  
Steven Carlip
Keyword(s):  
Gravitational Waves ◽  
Gravitational Radiation ◽  
Field Approximation ◽  
Weak Field ◽  
Quadrupole Moments ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Compact Binary ◽  
Speed Of Gravity ◽  
Weak Field Approximation

In the weak field approximation, the Einstein field equations can be solved, and lead to the prediction of gravitational waves. After showing that gravitational radiation depends on changing quadrupole moments, this chapter describes the production, propagation, and detection of gravitational waves. It includes discussions of the speed of gravity, detectors, the “chirp” waveform for a compact binary system, and the nature of astrophysical sources.

scholarly journals The Metric of Space-Time Curvature in a Weak Gravitational Field and it’s Consequence in Newtonian Approximation

2020 ◽  
pp. 87-92
Keyword(s):  
Gravitational Field ◽  
Dimensional Space ◽  
Empty Space ◽  
Field Approximation ◽  
Weak Field ◽  
Newtonian Mechanics ◽  
Perfect Field ◽  
Weak Gravitational Field ◽  
Weak Field Approximation ◽  
Potential Tensor

In Newtonian mechanics, space and time are separate but in General, Relativity is unified. It is considered that the space in the weak-field approximation is quasi-static and it arises from a perfect field whose particles have very small velocity in comparison to light velocity in this coordinate system and the metric is a gravitational potential tensor of rank two which implies the field of empty space. If each point of an area in N-dimensional space there existed a corresponding definite tensor, where the components of the tensor are the function of space and space acts as the strong or weak gravitational field.

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