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 Physics , 1997, Abstract: The Lorentz group is the fundamental language for space-time symmetries of relativistic particles. This group can these days be derived from the symmetries observed in other branches of physics. It is shown that this group can be derived from optical filters. The group O(2,1) is appropriate for attenuation filters, while the O(3) group describes phase-shift filters. The combined operation leads to a two-by-two representation of the six-parameter Lorentz group. It is shown also that the bilinear representation of this group is the natural language for the polarization optics.
 Symmetry , 2013, DOI: 10.3390/sym5030233 Abstract: Henri Poincaré formulated the mathematics of Lorentz transformations, known as the Poincaré group. He also formulated the Poincaré sphere for polarization optics. It is shown that these two mathematical instruments can be derived from the two-by-two representations of the Lorentz group. Wigner’s little groups for internal space-time symmetries are studied in detail. While the particle mass is a Lorentz-invariant quantity, it is shown to be possible to address its variations in terms of the decoherence mechanism in polarization optics.
 Physics , 2013, Abstract: Henri Poincar\'e formulated the mathematics of Lorentz transformations, known as the Poincar\'e group. He also formulated the Poincar\'e sphere for polarization optics. It is shown that these two mathematical instruments can be derived from the two-by-two representations of the Lorentz group. Wigner's little groups for internal space-time symmetries are studied in detail. While the particle mass is a Lorentz-invariant quantity, it is shown possible to address its variations in terms of the decoherence mechanism in polarization optics.
 Milton Ferreira Mathematics , 2007, Abstract: We consider the conformal group of the unit sphere $S^{n-1},$ the so-called proper Lorentz group Spin$^+(1,n),$ for the study of spherical continuous wavelet transforms (CWT). Our approach is based on the method for construction of general coherent states associated to square integrable group representations over homogeneous spaces. The underlying homogeneous space is an extension to the whole of the group Spin$^+(1,n)$ of the factorization of the gyrogroup of the unit ball by an appropriate gyro-subgroup. Sections on this homogeneous space are constituted by rotations of the subgroup Spin$(n)$ and M\"{o}bius transformations of the type $\phi_a(x)=(x-a)(1+ax)^{-1},$ where $a$ belongs to a given section on a homogeneous space of the unit ball. This extends in a natural way the work of Antoine and Vandergheynst to anisotropic conformal dilations.
 Physics , 2004, Abstract: It has been almost one hundred years since Einstein formulated his special theory of relativity in 1905. He showed that the basic space-time symmetry is dictated by the Lorentz group. It is shown that this group of Lorentz transformations is not only applicable to special relativity, but also constitutes the scientific language for optical sciences. It is noted that coherent and squeezed states of light are representations of the Lorentz group. The Lorentz group is also the basic underlying language for classical ray optics, including polarization optics, interferometers, the Poincare\'e sphere, one-lens optics, multi-lens optics, laser cavities, as well multilayer optics.
 Albert Stebbins Physics , 1996, Abstract: This paper details a description of the pattern of galaxy image distortion over the entire sky caused by the gravitational lensing which is the result of large scale inhomogeneities in our universe. We present a tensor spherical harmonic formalism to describe this pattern, giving many useful formulae. This is applied to density inhomogeneities, where we compute the angular power spectrum of the shear pattern, as well as the noise properties due to finite galaxy sampling and cosmic variance. We show that a detectable level of shear is present for very nearby galaxies, $z\simlt0.2$. For such a shallow sample much of the largest signal-to-noise comes from very large angular scales, $\theta\simgt10^\circ$, although it is in the form of very small shear at a level $\simlt10^{-3}$.
 Physics , 2011, DOI: 10.1051/0004-6361/201117010 Abstract: We present a method to constrain cosmic topology from the distribution of astronomical objects projected on the celestial sphere. This is an extension of the 3D method introduced in Fujii & Yoshii (2011) that is to search for a pair of pairs of observed objects (quadruplet) linked by a holonomy, i.e., the method we present here is to search for a pair of celestial sphere $n$-tuplets for $n \geq 3$. We find, however, that this method is impractical to apply in realistic situations due to the small signal to noise ratio. We conclude therefore that it is unrealistic to constrain the topology of the Universe from the celestial distribution, and the 3D catalogs are necessary for the purpose.
 Mathematics , 2004, Abstract: We show a geometric rigidity of isometric actions of non compact (semisimple) Lie groups on Lorentz manifolds. Namely, we show that the manifold has a warped product structure of a Lorentz manifold with constant curvature by a Riemannian manifold.
 Iurii Kudriavtcev Physics , 2010, Abstract: We performed the check of supposition about the possibility of manifestation of the previously observed phenomenon of central symmetry of the celestial sphere through existence of the opposite quasars. We discovered the existence of some pairs of quasars located opposite each other with close by form profiles magnitudes of luminosity in the ranges u, g, r, i, z, when correlation coefficient close to 1. We discovered that the percentage of the pairs with correlation coefficients Rxy>0.98 for the opposite located quasars is significantly higher than that for the random pairs. The analysis of the dependence of this exceedance from the artificial breaking of the central symmetry has shown, that it practically disappears with symmetry breaking by more than 0.05 degrees. Thus we can confirmed the manifestation of the central symmetry of celestial sphere through existence of the central symmetrical pairs of quasars, which can be interpreted as the pairs of images of the same object. We shown the possibility of a theoretical modeling of the observed dependencies in the closed Universe model. It can be supposed, that a relatively small amount of the discovered pairs of the opposite quasars is conditioned by the fact, that the opposite objects for most of the quasars are galaxies, which are not included to the chosen as initial source of data quasar catalog SDSS-DR5.
 Y. S. Kim Physics , 2014, Abstract: It is noted that the Poincar\'e sphere for polarization optics contains the symmetries of the Lorentz group. The sphere is thus capable of describing the internal space-time symmetries dictated by Wigner's little groups. For massive particles, the little group is like the three-dimensional rotation group, while it is like the two-dimensional Euclidean group for massless particles. It is shown that the Poincar\'e sphere, in addition, has a symmetry parameter corresponding to reducing the particle mass from a positive value to zero. The Poincar\'e sphere thus the gives one unified picture of Wigner's little groups for massive and massless particles.
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