scholarly journals Some remarks on an old problem of radiation and gravity

2014 ◽  
Vol 23 (12) ◽  
pp. 1442008 ◽  
Author(s):  
C. S. Unnikrishnan ◽  
George T. Gillies
Keyword(s):  
Gravitational Field ◽  
Equivalence Principle ◽  
Charged Particles ◽  
Free Fall ◽  
Magnetic Component ◽  
Far Field ◽  
Universality Of Free Fall ◽  
Global Nature

The assumed universality of the equivalence principle suggests that a particle in a gravitational field has identical physics to one in an accelerated frame. Yet, energy considerations prohibit radiation from a static particle in a gravitational field while the accelerating counterpart emits. Solutions to the fundamental problems of radiation from charges in a gravitational field and consequences to the equivalence principle usually contrast the far-field and global nature of radiation with the local validity of the equivalence principle. Here, we suggest reliable physical solutions that recognizes the essential need for motional currents and the magnetic component for radiation to occur. Our discussion reiterates the need for a fresh careful look at universality of free fall (UFF) for charged particles in a gravitational field.

scholarly journals Interesting Examples of Violation of the Classical Equivalence Principle but Not of the Weak One

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Antonio Accioly ◽  
Wallace Herdy
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Gravitational Field ◽  
Experimental Test ◽  
Equivalence Principle ◽  
Free Fall ◽  
Higher Order ◽  
Tree Level ◽  
Quantum Particles ◽  
Bohr Atom

The equivalence principle (EP) and Schiff’s conjecture are discussed en passant, and the connection between the EP and quantum mechanics is then briefly analyzed. Two semiclassical violations of the classical equivalence principle (CEP) but not of the weak one (WEP), i.e., Greenberger gravitational Bohr atom and the tree-level scattering of different quantum particles by an external weak higher-order gravitational field, are thoroughly investigated afterwards. Next, two quantum examples of systems that agree with the WEP but not with the CEP, namely, COW experiment and free fall in a constant gravitational field of a massive object described by its wave-function Ψ, are discussed in detail. Keeping in mind that, among the four examples focused on in this work only COW experiment is based on an experimental test, some important details related to it are presented as well.

Higher-order gravity and the classical equivalence principle

2017 ◽  
Vol 32 (34) ◽  
pp. 1750185
Author(s):  
Antonio Accioly ◽  
Wallace Herdy
Keyword(s):  
Gravitational Field ◽  
Equivalence Principle ◽  
Free Fall ◽  
Higher Order ◽  
Tree Level ◽  
Weak Equivalence ◽  
Weak Equivalence Principle ◽  
Quantum Particles ◽  
Higher Order Gravity ◽  
Energy Dependent

As is well known, the deflection of any particle by a gravitational field within the context of Einstein’s general relativity — which is a geometrical theory — is, of course, nondispersive. Nevertheless, as we shall show in this paper, the mentioned result will change totally if the bending is analyzed — at the tree level — in the framework of higher-order gravity. Indeed, to first order, the deflection angle corresponding to the scattering of different quantum particles by the gravitational field mentioned above is not only spin dependent, it is also dispersive (energy-dependent). Consequently, it violates the classical equivalence principle (universality of free fall, or equality of inertial and gravitational masses) which is a nonlocal principle. However, contrary to popular belief, it is in agreement with the weak equivalence principle which is nothing but a statement about purely local effects. It is worthy of note that the weak equivalence principle encompasses the classical equivalence principle locally. We also show that the claim that there exists an incompatibility between quantum mechanics and the weak equivalence principle, is incorrect.

Testing the Universality of Free Fall for Charged Particles in Space

2004 ◽  
Vol 36 (3) ◽  
pp. 571-591 ◽  
Author(s):  
Hansjörg Dittus ◽  
Claus Lämmerzahl ◽  
Hanns Selig
Keyword(s):  
Charged Particles ◽  
Free Fall ◽  
Universality Of Free Fall

The Nordström theory

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
Gravitational Field ◽  
Scalar Field ◽  
Equivalence Principle ◽  
Charged Particles ◽  
Inertial Mass ◽  
Massless Scalar ◽  
Weak Equivalence ◽  
Massless Scalar Field ◽  
Particle Charge ◽  
Weak Equivalence Principle

This chapter turns to the description of the interaction of a scalar field with particles which ‘feel’—that is, ‘charged’ particles. If the field is massless, and therefore long-range, and if the particle charge corresponds to its inertial mass, we have what is known as Nordström theory, a coherent theory of gravity which, however, disagrees with experiment. Nordström theory describes gravity by means of a massless scalar field φ‎. According to the ‘weak equivalence principle’, gravitational masses are equal to inertial masses, m = mg. When velocities are small, the gravitational field created is also weak.

scholarly journals GRAVITATIONAL EFFECTS OF ROTATING BODIES

2001 ◽  
Vol 16 (12) ◽  
pp. 789-794 ◽  
Author(s):  
YUAN-ZHONG ZHANG ◽  
JUN LUO ◽  
YU-XIN NIE
Keyword(s):  
Gravitational Field ◽  
Equivalence Principle ◽  
Free Fall ◽  
Coupling Model ◽  
Spin Coupling ◽  
Gravitational Effects ◽  
Perihelion Precession ◽  
Upper Limit ◽  
Spin Spin Coupling ◽  
Rotating Bodies

We study two types of effects of gravitational field on mechanical gyroscopes (i.e. rotating extended bodies). The first depends on special relativity and equivalence principle. The second is related to the coupling (i.e. a new force) between the spins of mechanical gyroscopes, which would violate the equivalent principle. In order to give a theoretical prediction to the second we suggest a spin–spin coupling model for two mechanical gyroscopes. An upper limit on the coupling strength is then determined by using the observed perihelion precession of the planet's orbits in solar system. We also give predictions violating the equivalence principle for free-fall gyroscopes.

A nonmetric theory of gravity

2016 ◽  
Vol 25 (11) ◽  
pp. 1640017 ◽  
Author(s):  
Wei-Tou Ni
Keyword(s):  
Time Reversal ◽  
Coordinate Transformation ◽  
Equivalence Principle ◽  
Free Fall ◽  
Weak Equivalence ◽  
Time Reversal Invariance ◽  
Weak Equivalence Principle ◽  
Universality Of Free Fall ◽  
Reversal Invariance ◽  
Theory Of Gravity

A nonmetric theory of gravity is presented, which agrees with all experiments to date. It possesses a Lagrangian-based nonmetric (i.e. nonminimum) coupling between electromagnetism and gravity which has complete continuous-coordinate-transformation symmetry but violates parity and time-reversal-invariance. The theory predicts the universality of free fall for test bodies, i.e. it obeys the Weak Equivalence Principle (WEP). But due to the nonmetrical coupling between electromagnetism and gravity, it violates the Einstein Equivalence Principle (EEP). Hence, this theory disproves the conjecture due to Schiff which states that any gravitation theory that obeys the WEP must also, unavoidably, obey the EEP. Further examination of the empirical status implications of the EEP is therefore urged.

SATELLITE TEST OF THE EQUIVALENCE PRINCIPLE: OVERVIEW AND PROGRESS

2007 ◽  
Vol 16 (12a) ◽  
pp. 2215-2225 ◽  
Author(s):  
JEFFERY J. KOLODZIEJCZAK ◽  
JOHN MESTER
Keyword(s):  
Present State ◽  
Equivalence Principle ◽  
Free Fall ◽  
Development Plan ◽  
Current Status ◽  
Technology Readiness ◽  
Gravity Probe B ◽  
Universality Of Free Fall ◽  
Recent Advances ◽  
Gravity Probe

STEP, the Satellite Test of the Equivalence Principle, is reviewed and the current status of the project is discussed. This space-based experiment will test the universality of free fall and is designed to advance the present state of knowledge by over five orders of magnitude. The international STEP collaboration is pursuing a development plan to improve and verify the technology readiness of key systems. We discuss recent advances with an emphasis on accelerometer fabrication and tests. Critical technologies successfully demonstrated in flight by the Gravity Probe B mission also contribute to progress.

scholarly journals Satellite Laser-Ranging as a Probe of Fundamental Physics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ignazio Ciufolini ◽  
Richard Matzner ◽  
Antonio Paolozzi ◽  
Erricos C. Pavlis ◽  
Giampiero Sindoni ◽  
...  
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Equivalence Principle ◽  
Free Fall ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
Weak Equivalence ◽  
Fundamental Physics ◽  
Weak Equivalence Principle ◽  
Gravitational Theories

Abstract Satellite laser-ranging is successfully used in space geodesy, geodynamics and Earth sciences; and to test fundamental physics and specific features of General Relativity. We present a confirmation to approximately one part in a billion of the fundamental weak equivalence principle (“uniqueness of free fall”) in the Earth’s gravitational field, obtained with three laser-ranged satellites, at previously untested range and with previously untested materials. The weak equivalence principle is at the foundation of General Relativity and of most gravitational theories.

PATCH EFFECT IN CYLINDRICAL GEOMETRY: THE STEP ACCELEROMETER

2012 ◽  
Vol 12 ◽  
pp. 131-135
Author(s):  
VALERIO FERRONI ◽  
ALEXANDER SILBERGLEIT
Keyword(s):  
Precision Measurement ◽  
Equivalence Principle ◽  
Free Fall ◽  
Metallic Surfaces ◽  
Actual Distribution ◽  
Differential Motion ◽  
Universality Of Free Fall ◽  
Finite Distance ◽  
Set Up ◽  
Cylindrical Test

The actual distribution of charges on a metal does not guarantee its surface to be equipotential because of the impurities and microcrystal structure of the material. This phenomenon, known as patch effect, is responsible for the mutual force and torque between two metallic surfaces at a finite distance. Patch effect is important for any precision measurement whose set-up includes conducting surfaces in a closed proximity to each other. This is particularly true for the Satellite Test of the Equivalence Principle experiment where the differential motion of cylindrical test masses will be used to test the universality of free fall to an unprecedented accuracy of about 1 part in 1018.

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