NEW TESTS OF THE GRAVITATIONAL REDSHIFT EFFECT

1990 ◽  
Vol 05 (23) ◽  
pp. 1809-1813 ◽  
Author(s):  
TIMOTHY P. KRISHER
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Equivalence Principle ◽  
Total Mass ◽  
Good Accuracy ◽  
Gravitational Redshift ◽  
Outer Planets ◽  
The Earth ◽  
Detailed Composition ◽  
Future Status

Tests of the gravitational redshift effect provide a way to check the validity of the Einstein Equivalence Principle (EEP) and, more specifically, of general relativity. If the EEP is valid, then the redshift should be the same for different clocks. Also, according to general relativity, the redshift should depend upon only the total mass of a gravitating body without reference to its detailed composition. These predictions have been tested mainly in the gravitational field of the Earth. It is now possible to measure, with space probes, the redshift effect to good accuracy in the vicinity of other bodies in the solar system, in particular at the massive outer planets. The present and future status of these experiments is discussed.

Gravitational “Doppler Boosting / De-boosting” Effect within the Framework of General Relativity

2021 ◽  
Vol 10 (4) ◽  
Author(s):  
Mark Zilberman ◽  
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Special Relativity ◽  
Spectral Index ◽  
Equivalence Principle ◽  
Relativistic Effect ◽  
Gravitational Redshift ◽  
Astronomical Observations ◽  
Complete Set ◽  
Einstein's Equivalence Principle

The “Doppler boosting / de-boosting” relativistic effect increases / decreases the apparent luminosity of approaching / receding sources of radiation. This effect was analyzed in detail within the Special Relativity framework and was confirmed in many astronomical observations. It is however not clear if “Doppler boosting / de-boosting” exists in the framework of General Relativity as well, and if it exists, which equations describe it. The “Einstein’s elevator” and Einstein’s “Equivalence principle” allow to obtain the formula for “Doppler boosting / de-boosting” for a uniform gravitational field within the vicinity of the emitter/receiver. Under these simplified conditions, the ratio ℳ between apparent (L) and intrinsic (Lo) luminosity can be conveniently represented using source’s spectral index α and gravitational redshift z as ℳ(z, α) ≡ L/Lo=(z+1)^(α-3). This is the first step towards the complete set of equations that describe the gravitational "Doppler boosting / de-boosting" effect within the General Relativity framework including radial gravitational field and arbitrary values of distance h between emitter and receiver.

The Equivalence Principle

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
General Relativity ◽  
Special Relativity ◽  
Equivalence Principle ◽  
Time Dilation ◽  
Gravitational Redshift ◽  
Coordinate Systems ◽  
Spacetime Metric

The equivalence principle is an important thinking tool to bootstrap our thinking from the inertial coordinate systems of special relativity to the more complex coordinate systems that must be used in the presence of gravity (general relativity). The equivalence principle posits that at a given event gravity accelerates everything equally, so gravity is equivalent to an accelerating coordinate system.This conjecture is well supported by precise experiments, so we explore the consequences in depth: gravity curves the trajectory of light as it does other projectiles; the effects of gravity disappear in a freely falling laboratory; and gravitymakes time runmore slowly in the basement than in the attic—a gravitational form of time dilation. We show how this is observable via gravitational redshift. Subsequent chapters will build on this to show how the spacetime metric varies with location.

Red shift of photon frequency in the gravitational field

2021 ◽  
Author(s):  
Jin Tong Wang ◽  
Jiangdi Fan ◽  
Aaron X. Kan
Keyword(s):  
General Relativity ◽  
Quantum Mechanics ◽  
Gravitational Field ◽  
Gravitational Potential ◽  
Schrodinger Equation ◽  
Red Shift ◽  
Relativity Theory ◽  
Gravitational Redshift ◽  
General Relativity Theory ◽  
Photon Frequency

It has been well known that there is a redshift of photon frequency due to the gravitational potential. Scott et al. [Can. J. Phys. 44 (1966) 1639, https://doi.org/10.1139/p66-137 ] pointed out that general relativity theory predicts the gravitational redshift. However, using the quantum mechanics theory related to the photon Hamiltonian and photon Schrodinger equation, we calculate the redshift due to the gravitational potential. The result is exactly the same as that from the general relativity theory.

scholarly journals Gravitational Redshifts and the Mass-Radius Relation

1989 ◽  
Vol 114 ◽  
pp. 401-407
Author(s):  
Gary Wegner
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Solar System ◽  
White Dwarf ◽  
Sufficient Accuracy ◽  
Gravitational Redshift ◽  
Principle Of Equivalence ◽  
Field Equations ◽  
Tests Of General Relativity ◽  
Gravitational Field Equations

The gravitational redshift is one of Einstein’s three original tests of General Relativity and derives from time’s slowing near a massive body. For velocities well below c, this is represented with sufficient accuracy by:As detailed by Will (1981), Schiff’s conjecture argues that the gravitational redshift actually tests the principle of equivalence rather than the gravitational field equations. For low redshifts, solar system tests give highest accuracy. LoPresto & Pierce (1986) have shown that the redshift at the Sun’s limb is good to about ±3%. Rocket experiments produce an accuracy of ±0.02% (Vessot et al. 1980), while for 40 Eri B the best white dwarf, the observed and predicted VRS agree to only about ±_5% (Wegner 1980).

INFLUENCE OF EARTH’S GRAVITY ON (g−2) MEASUREMENTS

1988 ◽  
Vol 03 (13) ◽  
pp. 1227-1229 ◽  
Author(s):  
A. WIDOM ◽  
C.C. CHEN
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Space Time ◽  
The Earth ◽  
Background Space

Experimental probes of the anomalous magnetic moment of the muon, which are sufficiently sensitive to probe electro-weak unification contributions to (g−2), are also sufficiently sensitive to test an interesting feature of general relativity. The gravitational field of the earth produces a background space-time metric which will influence (g−2) measurements.

scholarly journals RADIATION FROM A UNIFORMLY ACCELERATED CHARGE IN THE OUTSKIRTS OF A WORMHOLE THROAT

2000 ◽  
Vol 15 (36) ◽  
pp. 2219-2228 ◽  
Author(s):  
LUIS A. ANCHORDOQUI ◽  
S. CAPOZZIELLO ◽  
G. LAMBIASE ◽  
DIEGO F. TORRES
Keyword(s):  
General Relativity ◽  
Refractive Index ◽  
Gravitational Field ◽  
Equivalence Principle ◽  
Ricci Tensor ◽  
Energy Condition ◽  
Theoretical Background ◽  
Traversable Wormholes ◽  
Spatial Part ◽  
Accelerated Charge

Using traversable wormholes as theoretical background, we revisit a deep question of general relativity: Does a uniformly accelerated charged particle radiate? We particularize to the recently proposed gravitational Čerenkov radiation, that happens when the spatial part of the Ricci tensor is negative. If (3+1)Rii<0 the matter threading the gravitational field violates the weak energy condition. In this case, the effective refractive index for light is larger than 1, i.e. particles propagate faster than photons in that medium. This leads to a violation of the equivalence principle.

scholarly journals TORSION GRAVITY: A REAPPRAISAL

2004 ◽  
Vol 13 (10) ◽  
pp. 2193-2240 ◽  
Author(s):  
H. I. ARCOS ◽  
J. G. PEREIRA
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Equivalence Principle ◽  
Degrees Of Freedom ◽  
Gauge Theories ◽  
Point Of View ◽  
Affine Groups ◽  
Conceptual Question ◽  
Curvature And Torsion ◽  
Strong Equivalence Principle

The role played by torsion in gravitation is critically reviewed. After a description of the problems and controversies involving the physics of torsion, a comprehensive presentation of the teleparallel equivalent of general relativity is made. According to this theory, curvature and torsion are alternative ways of describing the gravitational field, and consequently related to the same degrees of freedom of gravity. However, more general gravity theories, like for example Einstein–Cartan and gauge theories for the Poincaré and the affine groups, consider curvature and torsion as representing independent degrees of freedom. By using an active version of the strong equivalence principle, a possible solution to this conceptual question is reviewed. This solution ultimately favors the teleparallel point of view, and consequently the completeness of general relativity. A discussion of the consequences for gravitation is presented.

scholarly journals ROTATABLE-TORSION-BALANCE EQUIVALENCE PRINCIPLE EXPERIMENT FOR THE SPIN-POLARIZED HoFe3

2001 ◽  
Vol 16 (12) ◽  
pp. 763-773 ◽  
Author(s):  
LI-SHING HOU ◽  
WEI-TOU NI
Keyword(s):  
Gravitational Field ◽  
Equivalence Principle ◽  
Rotation Period ◽  
Torsion Balance ◽  
Experimental Results ◽  
Polarized Electrons ◽  
The Earth ◽  
Spin Polarized ◽  
Order Of Magnitude

We use a rotatable torsion balance to perform an equivalence principle test on a magnetically shielded spin-polarized body of HoFe 3. With a rotation period of one hour, the period of possible signal is reduced from one solar day by 24 times, and hence the 1/f noise is greatly reduced. Our present experimental results give a limit of (-0.68 ± 0.90) × 10-9 on the Eötvös parameter [Formula: see text] and a limit of (1.8 ± 5.3) × 10-9 on the Eötvös parameter [Formula: see text] of equivalence of the polarized body compared with unpolarized aluminum–brass cylinders in the solar gravitational field, and a limit (-0.24 ± 0.55) × 10-9 on the Eötvös parameter [Formula: see text] in the earth gravitational field. This improves the previous limit on the Eötvös parameter [Formula: see text] for polarized electrons in the solar gravitational field by one order of magnitude.

DELTA GRAVITY AND THE ACCELERATED EXPANSION OF THE UNIVERSE

2011 ◽  
Vol 20 (supp01) ◽  
pp. 65-72
Author(s):  
JORGE ALFARO
Keyword(s):  
General Relativity ◽  
Gravitational Field ◽  
Cosmological Constant ◽  
Equivalence Principle ◽  
Equations Of Motion ◽  
Accelerated Expansion ◽  
Symmetric Tensors ◽  
Test Particles ◽  
Expansion Of The Universe ◽  
The Universe

We study a model of the gravitational field based on two symmetric tensors. The equations of motion of test particles are derived. We explain how the Equivalence principle is recovered. Outside matter, the predictions of the model coincide exactly with General Relativity, so all classical tests are satisfied. In Cosmology, we get accelerated expansion without a cosmological constant.

scholarly journals Testing the weak equivalence principle with macroscopic proof masses on ground and in space: A brief review

2014 ◽  
Vol 30 ◽  
pp. 1460254 ◽  
Author(s):  
Anna M. Nobili
Keyword(s):  
General Relativity ◽  
Equivalence Principle ◽  
Free Fall ◽  
Experimental Tests ◽  
Torsion Balance ◽  
Experimental Fact ◽  
Weak Equivalence ◽  
Weak Equivalence Principle ◽  
Tests Of General Relativity ◽  
The Earth

General relativity is founded on the experimental fact that in a gravitational field all bodies fall with the same acceleration regardless of their mass and composition. This is the weak equivalence principle, or universality of free fall. Experimental evidence of a violation would require either that general relativity is to be amended or that another force of nature is at play. In 1916 Einstein brought as evidence the torsion balance experiments by Eötvös, to 10-8–10-9. In the 1960s and early 70s, by exploiting the "passive" daily rotation of the Earth, torsion balance tests improved to 10-11 and 10-12. More recently, active rotation of the balance at higher frequencies has reached 10-13. No other experimental tests of general relativity are both so crucial for the theory and so precise and accurate. If a similar differential experiment is performed inside a spacecraft passively stabilized by 1 Hz rotation while orbiting the Earth at ≃ 600 km altitude the test would improve by 4 orders of magnitude, to 10-17, thus probing a totally unexplored field of physics. This is unique to weakly coupled concentric macroscopic test cylinders inside a rapidly rotating spacecraft.

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