共查询到20条相似文献,搜索用时 15 毫秒
1.
An estimation of the photon rest-mass is performed by considering a single photon under the action of a gravitational field. In fact, the wavelength dependence of this mass is expressed in analytical form in connection with the fact that the photon velocity depends upon wavelength. 相似文献
2.
An upper bound for the photon mass is calculated by regarding photons under the action of a gravitational field within the framework of fluctuations in the quantum vacuum. Furthermore, some considerations upon zero-point energy are made in order to estimate interaction range in terms of distance. 相似文献
3.
《Optics and Lasers in Engineering》2007,45(4):478
The interferometric gravitational wave detectors represent the ultimate evolution of the classical Michelson interferometer. In order to measure the signal produced by the passage of a gravitational wave, they aim to reach unprecedent sensitivities in measuring the relative displacements of the mirrors. One of them, the 3-km-long Virgo gravitational wave antenna, which will be particularly sensitive in the low-frequency range (10–100 Hz), is presently in its commissioning phase. In this paper the various techniques developed in order to reach its target extreme performance are outlined. 相似文献
4.
Th. Bourdel M. Doser A.D. Ernest A.Yu. Voronin V.V. Voronin 《Comptes Rendus Physique》2011,12(8):779-790
The subjects presented here are very different. Their common feature is that they all involve quantum phenomena in a gravitational field: gravitational quantum states of ultracold antihydrogen above a material surface and measuring a gravitational interaction of antihydrogen in AEGIS, a quantum trampoline for ultracold atoms, and a hypothesis on naturally occurring gravitational quantum states, an Eötvös-type experiment with cold neutrons and others. Considering them together, however, we could learn that they have many common points both in physics and in methodology. 相似文献
5.
Berry phases mix states of positive and negative energy in the propagation of fermions and bosons in external gravitational and electromagnetic fields and generate Zitterbewegung oscillations. The results are valid in any reference frame and to any order of approximation in the metric deviation. 相似文献
6.
The direct observation of gravitational waves (GW) in the near future, and the corresponding determination of the number of independent polarizations, is a powerful tool to test general relativity and alternative theories of gravity. In the present work we use the Newman–Penrose formalism to characterize GWs in quadratic gravity and in a particular class of f(R) Lagrangians. We find that both quadratic gravity and the f(R) theory belong to the most general invariant class of GWs, i.e., they can present up to six independent polarizations of GWs. For a particular combination of the parameters, we find that quadratic gravity can present up to five polarizations states. On the other hand, if we use the Palatini approach for f(R) theories, GWs present only the usual two transverse-traceless polarizations such as in general relativity. Thus, we conclude that the observation of GWs can strongly constrain the suitable formalism for these theories. 相似文献
7.
Bose–Einstein condensation of two- and three-dimensional boson gases confined in the one-dimensional gravitational field is investigated. Using the semiclassical approximation method, the expressions for the BEC transition temperature, condensate fraction, heat capacity and the entropy of the system are obtained. The heat capacities of the systems with D =1, 2, 3 (D is the dimension) at the critical temperature are discussed. We find that for the 1-D and 2-D boson systems, the heat capacities are continuous, but for the 3-D case there is a gap at the critical temperature Tc. The entropies of the systems with D=1, 2, 3 are also studied in detail. It is found that the entropies increase with the increasing of the temperature T. 相似文献
8.
We discuss the production of particles via interaction with the earth’s gravitational field. Explicit calculations are done
for high energy scalars passing through earth’s gravitational field. We show for example, that the width for the scalar processφ→3φ can become comparable with a typical weak decay width at an energy scale of a few TeV. (Similar conclusions can be drawn about
particles that ultimately couple to some scalar field.) We speculate that similar processes may be responsible for many of
the anomalies in the 10–104 TeV experimental data. 相似文献
9.
Photon motion in a Michelson interferometer is re-analyzed in terms of both geometrical optics and wave optics.The classical paths of the photons in the background of a gravitational wave are derived from the Fermat principle,which is the same as the null geodesics in general relativity.The deformed Maxwell equations and the wave equations of electric fields in the background of a gravitational wave are presented in a flat-space approximation.Both methods show that even the envelope of the response of an interferometer depends on the frequency of a gravitational wave,but it is almost independent of the frequency of the mirror's vibrations. 相似文献
10.
The gravitational energy–momentum and angular momentum satisfy the algebra of the Poincaré group in the full phase space of
the teleparallel equivalent of general relativity. The expression for the gravitational energy–momentum may be written as
a surface integral in the three-dimensional spacelike hypersurface, whereas the definition for the angular momentum is given
by a volume integral. It turns out that in practical calculations of the angular momentum of the gravitational field generated
by localized sources like rotating neutron stars, the volume integral reduces to a surface integral, and the calculations
can be easily carried out. Similar to previous investigations in the literature, we show that the total angular momentum is
finite provided a certain asymptotic behaviour is verified. We discuss the dependence of the gravitational angular momentum
on the frame, and argue that it is a measure of the dragging of inertial frames. 相似文献
11.
Aidan Brooks Peter Veitch Jesper Munch Thu-Lan Kelly 《General Relativity and Gravitation》2005,37(9):1575-1580
We describe a novel off-axis Hartmann wavefront sensor, developed for the measurement of wavefront distortions induced in
the mirrors (test masses) of advanced gravitational wave interferometers by residual absorption of the circulating laser power. 相似文献
12.
B S Sathyaprakash 《Pramana》2001,56(4):457-475
The new millennium will see the upcoming of several ground-based interferometric gravitational wave antennas. Within the next
decade a space-based antenna may also begin to observe the distant Universe. These gravitational wave detectors will together
operate as a network taking data continuously for several years, watching the transient and continuous phenomena occurring
in the deep cores of astronomical objects and dense environs of the early Universe where gravity was extremely strong and
highly nonlinear. The network will listen to the waves from rapidly spinning non-axisymmetric neutron stars, normal modes
of black holes, binary black hole inspiral and merger, phase transitions in the early Universe, quantum fluctuations resulting
in a characteristic background in the early Universe. The gravitational wave antennas will open a new window to observe the
dark Universe unreachable via other channels of astronomical observations. 相似文献
13.
In a previous Letter, we have shown that the use of orthogonal ribbons could provide a better mirror suspension technique in interferometric gravitational wave antennas. One of the key improvements presented by the orthogonal ribbon is the reduction in the number of violin string modes in the direction of the laser. We have considered more elaborate geometries in recent simulations and obtained a suspension that provides further reduction in the number of violin string modes in the direction of the laser, as well as in the direction orthogonal to the laser. This thin walled niobium tube suspension exhibits a reduction in the number of violin modes to 5 in each direction up to a frequency of 5 kHz. Furthermore, the violin mode thermal noise peaks can be reduced in amplitude by 30 dB. 相似文献
14.
L. Cunningham P.G. Murray E.J. Elliffe K. Haughian M. Hendry I.W. Martin S. Rowan K.A. Strain C. Torrie A.A. van Veggel 《Physics letters. A》2010,374(39):3993-75
New measurements of the mechanical loss factors of hydroxide-catalysis bonds have been made and these have been found to be significantly lower than previously reported. We provide the first estimate for the resulting thermal noise limitation for a practical test mass geometry for next generation gravitational wave detectors. 相似文献
15.
Laser interferometer gravitational wave detectors require very high optical quality test masses. We report the bulk Rayleigh scattering in high quality fused silica samples. Results show that the scattering of the high quality fused silica is similar for various grades of fused silica from Heraeus. The total integrated scattering is about 0.7 ppm cm− 1at 1064 nm wavelength, which agrees with the theoretical value calculated using known fused silica parameters. All samples show Rayleigh scattering ratio inhomogeneity of ~ 4%. 相似文献
16.
The model-to-image registration problem is a problem of determining the position and orientation (the pose) of a three-dimensional object with respect to a camera coordinate system. When there is no additional information available to constrain the pose of the object and to constrain the correspondence of object features to image features, the problem is also known as simultaneous pose and correspondence problem, or correspondenceless pose estimation problem. In this paper, we present a new algorithm, called extended gravitational pose estimation (EGPE), for determining the pose and correspondence simultaneously. The algorithm is based on gravitational pose estimation (GPE) algorithm. In our algorithm, the original GPE has been revised to deal with the problem with false image points. For problems with both occluded object points and false image points, we firstly applied single-link agglomerative clustering algorithm to pick out occluded object points when a local minimum has been found, then the revised GPE is applied again on the clustering result to update rotation and translation of the object model. EGPE has been verified on both synthetic images and real images. Empirical results show that EGPE is faster, more stable and reliable than most current algorithms, and can be used in real applications. 相似文献
17.
César H. Lenzi Nadja S. Magalhães César A. Costa Rubens M. Marinho Jr Helmo A. B. Araújo Odylio D. Aguiar 《General Relativity and Gravitation》2008,40(1):183-190
The direct detection of gravitational waves will provide valuable astrophysical information about many celestial objects.
Also, it will be an important test to general relativity and other theories of gravitation. The gravitational wave detector
SCHENBERG has recently undergone its first test run. It is expected to have its first scientific run soon. In this work the
data analysis system of this spherical, resonant mass detector is tested through the simulation of the detection of gravitational
waves generated during the inspiralling phase of a binary system. It is shown from the simulated data that it is not necessary
to have all six transducers operational in order to determine the source’s direction and the wave’s amplitudes. 相似文献
18.
We propose a universal method of computation of thermal noise in mirrors of gravitational wave interferometers based on first principles. We imagine a situation where a mirror is part of a Fabry–Perot cavity. The movement of the mirror's surface produces variation of the eigen frequency of the cavity, which is computed by evaluating the variation of the energy stored in cavity. We consider two particular examples: first, the thermal noise from a dielectric slab inside the Fabry–Perot cavity, and second, the polarization-dependent thermal noise in the folded cavity. 相似文献
19.
Paolo Maraner 《Physics letters. A》2009,373(31):2616-2619
The Kaluza-Klein reduction of 4d conformally flat spacetimes is reconsidered. The corresponding 3d equations are shown to be equivalent to 2d gravitational kink equations augmented by a centrifugal term. For space-like gauge fields and non-trivial values of the centrifugal term the gravitational kink solutions describe a spacetime that is divided in two disconnected regions. 相似文献
20.
We have studied micro-photoluminescence spectra of a self-assembled single GaAs quantum dot under 8 K. With strong pulsed excitation, the micro-photoluminescence spectrum shows bright emission lines originated from an exciton, a positively charged exciton, and a biexciton, together with weak lower energy emissions reflecting multi-excitonic structures with more carriers. We have identified the origins of these weak emission lines, and showed the existence of charged biexciton states, through single photon correlation measurements and excitation power dependence of the photoluminescence intensity. In addition, investigating the radiative recombination process of the charged biexciton, we have determined the electron–hole exchange energy in the GaAs quantum dot. 相似文献