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.

TORSION BALANCE EQUIVALENCE PRINCIPLE EXPERIMENT FOR THE SPIN-POLARIZED Dy6F23

1990 ◽  
Vol 05 (28) ◽  
pp. 2297-2303 ◽  
Author(s):  
YI CHOU ◽  
WEI-TOU NI ◽  
SHIH-LIANG WANG
Keyword(s):  
Gravitational Field ◽  
Equivalence Principle ◽  
Torsion Balance ◽  
Spin Polarized

We use a torsion balance to perform an equivalence principle test on a magnetically shielded spin-polarized body of Dy 6 F 23. The equivalence of this polarized body compared with unpolarized aluminium-brass cylinders is good to (3.1 ± 4.0) × 10−8 in the solar gravitational field.

THE EQUIVALENCE PRINCIPLE EXPERIMENT FOR SPIN-POLARIZED BODIES

1989 ◽  
Vol 04 (17) ◽  
pp. 1597-1603 ◽  
Author(s):  
CHANG-HUAIN HSIEH ◽  
PIN-YUN JEN ◽  
KAI-LI KO ◽  
KEH-YANN LI ◽  
WEI-TOU NI ◽  
...  
Keyword(s):  
Gravitational Field ◽  
Equivalence Principle ◽  
Spin Polarized

We perform an equivalence principle experiment for a magnetically shielded spin-polarized body of Dy 6 Fe 23. We use a single-pan mass comparator to compare the spin-polarized body with an unpolarized group of masses. The equivalence of spin-up and spin-down positions is good to (1.1 ±7.8)×10−9 in earth gravitational field.

NUCLEAR POLARIZATION AND THE EQUIVALENCE PRINCIPLE

1991 ◽  
Vol 06 (08) ◽  
pp. 659-668 ◽  
Author(s):  
J.M. DANIELS ◽  
WEI-TOU NI
Keyword(s):  
Gravitational Field ◽  
Equivalence Principle ◽  
Nuclear Polarization ◽  
Dilution Refrigerator ◽  
Experimental Scheme ◽  
Earth’S Gravitational Field ◽  
Spin Polarized ◽  
Solar Field

In this paper, we analyze the nuclear polarization of the spin-polarized Dy6Fe23 used in our two equivalence principle (EP) experiments. From this we infer the equivalence of polarized Dy in the earth’s gravitational field to be good to 10−3 and in the solar field to be good to 1.4×10−2. To increase the nuclear polarization in order to have better EP tests, we propose to use a dilution refrigerator to lower the temperature to 10 mK. We present a thorough analysis of our experimental scheme together with a discussion of perspectives.

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.

NEW EXPERIMENTAL LIMIT ON THE SPATIAL ANISOTROPY FOR POLARIZED ELECTRONS

1993 ◽  
Vol 08 (39) ◽  
pp. 3715-3725 ◽  
Author(s):  
SHIH-LIANG WANG ◽  
WEI-TOU NI ◽  
SHEAU-SHI PAN
Keyword(s):  
Magnetic Moments ◽  
Spin States ◽  
Polarized Electrons ◽  
Spatial Anisotropy ◽  
Cosmic Neutrino Background ◽  
Oscillation Analysis ◽  
The Earth ◽  
Spin Polarized ◽  
Vacuum States ◽  
Cosmic Neutrino

Is our laboratory in an isotropic state for spin states? For example, motion of the earth through the cosmic neutrino background would produce a term of the form gσ · v in the energy of an electron. Certain kinds of vacuum states have this effect on electrons too. To search for such a term or a term like g′σ · n where n is a particular direction in the universe, we use a torsion pendulum carrying a transversely spin-polarized ferrimagnetic Dy-Fe mass which exhibit orbital compensation of the electron intrinsic spin magnetic moments. With this magnetic compensated mass, pure-Fe and µ-metal shields reduced magnetic torques to a good extent. The searched terms would produce a sinusoidal oscillation of the pendulum with a period of one sidereal day. We have not detected such an oscillation. Analysis of our experimental results gives a limit 3.5×10−18 eV for the splitting of the spin states of an electron at rest on the Earth. Compared to previous results, this is an improvement of more than a factor of 2.

Structure of the terrain and gravitational field of the planets: Kaula’s rule as a consequence of the probability laws by A.N. Kolmogorov and his school

2019 ◽  
Vol 485 (4) ◽  
pp. 493-496
Author(s):  
E. B. Gledzer ◽  
G. S. Golitsyn
Keyword(s):  
Random Walk ◽  
Gravitational Field ◽  
Spherical Harmonics ◽  
Empirical Data ◽  
The Moon ◽  
Linear Coefficient ◽  
Water Flows ◽  
The Earth ◽  
Order Of Magnitude ◽  
Celestial Bodies

Kaula’s empirical rule has been known for more than 50 years: the coefficients of expansion over spherical harmonics for the fluctuations of the gravitational field and terrain of the planets decrease as the number of the harmonic squared. This was found for Venus, the Moon, Mars, the asteroid Vesta, and very small celestial bodies. The inverse-square line spectra were also found for various types of the Earth’s surface on a scale of up to a hundred kilometers. From this it follows that the spectra of the terrain slope angles are constant, i.e., “white noise”. This, they are delta-correlated horizontally. These are the assumptions under which the random walk laws were derived by A.N. Kolmogorov in 1934. Using them, the equation of the horizontal probability diffusion of the terrain with the linear coefficient diffusion D is derived. Based on the empirical data, D = 1.3 ± 0.3 m for the Earth, while for Venus it is almost an order of magnitude less. The slopes resist the wind; the rock crumbles, and the water flows down the slopes as well. This consideration turns Kaula’s rule into the random walk laws (over terrain) developed by Kolmogorov in 1934.

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.

SURFACE AND THIN FILM MAGNETISM WITH SPIN POLARIZED ELECTRONS

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-9-C8-16 ◽  
Author(s):  
H. C. Siegmann ◽  
D. Mauri ◽  
D. Scholl ◽  
E. Kay
Keyword(s):  
Thin Film ◽  
Polarized Electrons ◽  
Spin Polarized ◽  
Thin Film Magnetism

The analysis is geometrically stable orbits of spacecraft remote sensing of the Еarth

2018 ◽  
Vol 15 (1) ◽  
pp. 12-22
Author(s):  
V. M. Artyushenko ◽  
D. Y. Vinogradov
Keyword(s):  
Remote Sensing ◽  
Gravitational Field ◽  
State Vector ◽  
Semimajor Axis ◽  
The State ◽  
Zonal Harmonics ◽  
The Earth ◽  
Conditions Of Stability

The article reviewed and analyzed the class of geometrically stable orbits (GUO). The conditions of stability in the model of the geopotential, taking into account the zonal harmonics. The sequence of calculation of the state vector of GUO in the osculating value of the argument of the latitude with the famous Ascoli-royski longitude of the ascending node, inclination and semimajor axis. The simulation is obtained the altitude profiles of SEE regarding the all-earth ellipsoid model of the gravitational field of the Earth given 7 and 32 zonal harmonics.

Spheric radial basis functions in Mahalanobis measuring for displaying local field features

2019 ◽  
Vol 952 (10) ◽  
pp. 2-9
Author(s):  
Yu.M. Neiman ◽  
L.S. Sugaipova ◽  
V.V. Popadyev
Keyword(s):  
Gravitational Field ◽  
Quadratic Form ◽  
Local Field ◽  
Euclidean Distance ◽  
Basis Functions ◽  
Spherical Functions ◽  
Local Models ◽  
Stationary Field ◽  
Modeling Process ◽  
The Earth

As we know the spherical functions are traditionally used in geodesy for modeling the gravitational field of the Earth. But the gravitational field is not stationary either in space or in time (but the latter is beyond the scope of this article) and can change quite strongly in various directions. By its nature, the spherical functions do not fully display the local features of the field. With this in mind it is advisable to use spatially localized basis functions. So it is convenient to divide the region under consideration into segments with a nearly stationary field. The complexity of the field in each segment can be characterized by means of an anisotropic matrix resulting from the covariance analysis of the field. If we approach the modeling in this way there can arise a problem of poor coherence of local models on segments’ borders. To solve the above mentioned problem it is proposed in this article to use new basis functions with Mahalanobis metric instead of the usual Euclidean distance. The Mahalanobis metric and the quadratic form generalizing this metric enables us to take into account the structure of the field when determining the distance between the points and to make the modeling process continuous.

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