372 research outputs found
Two-parameter deformation of the Poincar\'e algebra
We examine a two-parameter ( ) deformation of the
Poincar\`e algebra which is covariant under the action of When
it yields the Poincar\`e algebra, while in the
limit we recover the classical quadratic algebra discussed
previously in \cite{ssy95}, \cite{sy95}. The analogues of the Pauli-Lubanski
vector and Casimirs and are found and a set of mutually
commuting operators is constructed.Comment: 10 pages, Latex2
Towards constructing one-particle representations of the deformed Poincar\'e algebra
We give a method for obtaining states of massive particle representations of
the two-parameter deformation of the Poincar\'e algebra proposed in
q-alg/9601010, q-alg/9505030 and q-alg/9501026. We discuss four procedures to
generate eigenstates of a complete set of commuting operators starting from the
rest state. One result of this work is the fact that upon deforming to the
quantum Poincar\'e algebra the rest state is split into an infinite number of
states. Another result is that the energy spectrum of these states is discrete.
Some curious residual degeneracy remains: there are states constructed by
applying different operators to the rest state which nevertheless are
indistinguishable by eigenvalues of all the observables in the algebra.Comment: 23 pages. New interpretation of the results is given: upon the
deformation the rest state of Poincar\'e algebra is split into an infinite
number of states with discrete energy spectrum. Title, abstract and
conclusion are change
Deformation Quantization of the Isotropic Rotator
We perform a deformation quantization of the classical isotropic rigid
rotator. The resulting quantum system is not invariant under the usual
chiral symmetry, but instead .Comment: 12pp, LATE
Lie-Poisson Deformation of the Poincar\'e Algebra
We find a one parameter family of quadratic Poisson structures on which satisfies the property {\it a)} that it is preserved
under the Lie-Poisson action of the Lorentz group, as well as {\it b)} that it
reduces to the standard Poincar\'e algebra for a particular limiting value of
the parameter. (The Lie-Poisson transformations reduce to canonical ones in
that limit, which we therefore refer to as the `canonical limit'.) Like with
the Poincar\'e algebra, our deformed Poincar\'e algebra has two Casimir
functions which we associate with `mass' and `spin'. We parametrize the
symplectic leaves of with space-time coordinates,
momenta and spin, thereby obtaining realizations of the deformed algebra for
the cases of a spinless and a spinning particle. The formalism can be applied
for finding a one parameter family of canonically inequivalent descriptions of
the photon.Comment: Latex file, 26 page
Lorentz Transformations as Lie-Poisson Symmetries
We write down the Poisson structure for a relativistic particle where the
Lorentz group does not act canonically, but instead as a Poisson-Lie group. In
so doing we obtain the classical limit of a particle moving on a noncommutative
space possessing invariance. We show that if the standard mass
shell constraint is chosen for the Hamiltonian function, then the particle
interacts with the space-time. We solve for the trajectory and find that it
originates and terminates at singularities.Comment: 18 page
Performance of the WaveBurst algorithm on LIGO data
In this paper we describe the performance of the WaveBurst algorithm which
was designed for detection of gravitational wave bursts in interferometric
data. The performance of the algorithm was evaluated on the test data set
collected during the second LIGO Scientific run. We have measured the false
alarm rate of the algorithm as a function of the threshold and estimated its
detection efficiency for simulated burst waveforms.Comment: proceedings of GWDAW, 2003 conference, 13 pages, 6 figure
Prospects for intermediate mass black hole binary searches with advanced gravitational-wave detectors
We estimated the sensitivity of the upcoming advanced, ground-based
gravitational-wave observatories (the upgraded LIGO and Virgo and the KAGRA
interferometers) to coalescing intermediate mass black hole binaries (IMBHB).
We added waveforms modeling the gravitational radiation emitted by IMBHBs to
detectors' simulated data and searched for the injected signals with the
coherent WaveBurst algorithm. The tested binary's parameter space covers
non-spinning IMBHBs with source-frame total masses between 50 and 1050
and mass ratios between and 1. We found that
advanced detectors could be sensitive to these systems up to a range of a few
Gpc. A theoretical model was adopted to estimate the expected observation
rates, yielding up to a few tens of events per year. Thus, our results indicate
that advanced detectors will have a reasonable chance to collect the first
direct evidence for intermediate mass black holes and open a new, intriguing
channel for probing the Universe over cosmological scales.Comment: 9 pages, 4 figures, corrected the name of one author (previously
misspelled
Surface Hardening Low Alloy Structural Steel By Laser Welding
The paper studied the degree of surface hardening of various low-alloy structural steels by laser weld overlays. Laser welding carried out on the âScannerâ and «Huffman HC-205.â Studies have been conducted microstructure and elemental composition of built-up layers and the heat-affected zones on steel substratesselected by scanning electron microscopy and X-ray microanalysis. There were also measured the microhardness and built according to the changes in the thickness microhardness themselves claddings and heat-affected zones. As a result, the optimal modes of application of the laser weld overlays on the substrate, allowing to minimize the size of the heat-affected zones and differences in microhardness values, whichreduces the likelihood of cracks and discontinuities.
Keywords: surface hardening, nickel alloy, laser claddin
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