共查询到20条相似文献,搜索用时 15 毫秒
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Schlamminger S Choi KY Wagner TA Gundlach JH Adelberger EG 《Physical review letters》2008,100(4):041101
We used a continuously rotating torsion balance instrument to measure the acceleration difference of beryllium and titanium test bodies towards sources at a variety of distances. Our result Deltaa(N),(Be-Ti)=(0.6+/-3.1)x10(-15) m/s2 improves limits on equivalence-principle violations with ranges from 1 m to infinity by an order of magnitude. The E?tv?s parameter is eta(Earth,Be-Ti)=(0.3+/-1.8)x10(-13). By analyzing our data for accelerations towards the center of the Milky Way we find equal attractions of Be and Ti towards galactic dark matter, yielding eta(DM,Be-Ti)=(-4+/-7)x10(-5). Space-fixed differential accelerations in any direction are limited to less than 8.8x10(-15) m/s2 with 95% confidence. 相似文献
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The breakdown of statistical homogeneity and isotropy of cosmic perturbations is a generic feature of ultra-large scale structure
of the cosmos, in particular, of non-trivial cosmic topology. The statistical isotropy (SI) of the cosmic microwave background
temperature fluctuations (CMB anisotropy) is sensitive to this breakdown on the largest scales comparable to, and even beyond
the cosmic horizon. We propose a set of measures,K
l
(l = 1, 2,3,...) which for non-zero values indicate and quantify statistical isotropy violations in a CMB map. We numerically
compute the predictedK
l
spectra for CMB anisotropy in flat torus universe models. Characteristic signatures of different models in theK
l
spectrum are noted. 相似文献
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Poolman HR Boersma DJ Harvey M Higinbotham DW Passchier I Six E Alarcon R van Amersfoort PW Bauer TS Boer Rookhuizen H van Den Brand JF van Buuren LD Bulten HJ Ent R Ferro-Luzzi M Geurts DG Heimberg P de Jager CW Klimin P Koop I Kroes F van Der Laan J Luijckx G Lysenko A Militsyn B Nesterenko I 《Physical review letters》2000,84(17):3855-3858
We report on first measurements with polarized electrons stored in a medium-energy ring and with a polarized internal target. Polarized electrons were injected at 442 MeV (653 MeV), and a partial (full) Siberian snake was employed to preserve the polarization. Longitudinal polarization at the interaction point and polarization lifetime of the stored electrons were determined with laser backscattering. Spin observables were measured for electrodisintegration of polarized 3He, with simultaneous detection of scattered electrons, protons, neutrons, deuterons, and 3He nuclei, over a large phase space. 相似文献
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Determination of the limit of photon mass and cosmic magnetic vector with rotating torsion balance 总被引:1,自引:0,他引:1
A rotating torsion balance method to detect the product of the photon mass squared and the ambient cosmic vector potential is proposed. This modulation method is efficacious whether the vector potential is fortuitously aligned with Earth's rotation axis or not, and the experimental precision of the modulation method can be improved by at least an order of magnitude compared to the statistical method. 相似文献
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Measurement of Newton's constant using a torsion balance with angular acceleration feedback 总被引:2,自引:0,他引:2
We measured Newton's gravitational constant G using a new torsion balance method. Our technique greatly reduces several sources of uncertainty compared to previous measurements: (1) It is insensitive to anelastic torsion fiber properties; (2) a flat plate pendulum minimizes the sensitivity due to the pendulum density distribution; (3) continuous attractor rotation reduces background noise. We obtain G = (6.674215+/-0.000092) x 10(-11) m3 kg(-1) s(-2); the Earth's mass is, therefore, M = (5.972245+/-0.000082) x 10(24) kg and the Sun's mass is M = (1.988435+/-0.000027) x 10(30) kg. 相似文献
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We report on a test of Lorentz invariance performed by comparing the resonance frequencies of one stationary optical resonator and one continuously rotating on a precision air bearing turntable. Special attention is paid to the control of rotation induced systematic effects. Within the photon sector of the standard model extension, we obtain improved limits on combinations of 8 parameters at a level of a few parts in 10(-16). For the previously least well known parameter we find [EQUATION: SEE TEXT]. Within the Robertson-Mansouri-Sexl test theory, our measurement restricts the isotropy violation parameter [EQUATION: SEE TEXT]. corresponding to an eightfold improvement with respect to previous nonrotating measurements. 相似文献
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The effects of electron exchange and spin orbit interaction in dissociative excitation processes in H2 molecules have been explored using excitation by polarized electrons. Observations of the circular and linear Stokes polarizations of the Balmer-alpha photons determined the alignment and orientation of the excited atomic hydrogen atoms, the excited molecular states, and the dissociative excitation processes via predissociation with short and long range transitions. 相似文献
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The design of a system to obtain polarized electrons and photons in the Tomsk synchrotron is considered. The spin motion in injectors-linear accelerators and microtrons is investigated. Results of the change in polarization during acceleration in the synchrotron are presented.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 23–28, June, 1977. 相似文献
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Radially polarized beams have attracted much attention and found many applications in many optical systems, recently. And generation of radially polarized beams is necessary for experimental research and applications. In this paper, a kind of generation method was proposed. Two beams are obtained by spatial light modulator and pi phase plate, and then interfere to form desirable radially polarized beams. Experimental results show that radially polarized beams are higher property, which shows this kind of interferential generation of radially polarized laser beams work effectively. 相似文献
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This Letter presents the results of a series of measurements of the Newtonian gravitational constant G using the compensated torsion balance developed at the Measurement Standards Laboratory. Since our last published result using the torsion balance in the compensated mode of operation [Meas. Sci. Technol. 10, 439 (1999)]], several improvements have been made to reduce the uncertainty in the final result. The new measurements have used both stainless steel and copper large masses. The values of G for the two sets of masses are in good agreement. After combining all of the measurements we get a value of G=6.673 87(0.000 27) x 10(-11) m3 kg(-1) s(-2). This new value is 5 parts in 10(5) smaller than our previous published values. 相似文献
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We analyze parameters of the partially linearly polarized thermal radio emission from the Moon taking the effects of radiative
heat transfer and surface roughness into account. The distributions of the Stokes parameters I, Q, and U over the visible
lunar disk are considered. The polarization parameters of the integral radio emission as functions of the frequency and the
Moon phase are obtained by integrating the Q and U distributions. We consider the possibility of using the Moon as a reference
source of partially linearly polarized radiation for space-borne and ground-based projects aimed at studying polarization
of the Galactic radio emission and the cosmic microwave background.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 7, pp. 593–606, July 2007. 相似文献
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H.C. Siegmann 《Physics Reports》1975,17(2):37-76
Information on electron polarization in magnetic materials has been obtained from optical absorption measurements, from photoemission studies and from tunneling and field emission experiments. The results obtained with different techniques are reviewed. Special emphasis is given to the analysis of the contradictory data obtained from ferromagnetic metals. Magnetic insulators and semiconductors tend to give results that can be interpreted within the framework of current interpretation schemes, but the results from metals call for new models of magnetism and electron emission. 相似文献
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