345 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
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
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
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
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
Lagrangian and Hamiltonian Formalism on a Quantum Plane
We examine the problem of defining Lagrangian and Hamiltonian mechanics for a
particle moving on a quantum plane . For Lagrangian mechanics, we
first define a tangent quantum plane spanned by noncommuting
particle coordinates and velocities. Using techniques similar to those of Wess
and Zumino, we construct two different differential calculi on .
These two differential calculi can in principle give rise to two different
particle dynamics, starting from a single Lagrangian. For Hamiltonian
mechanics, we define a phase space spanned by noncommuting
particle coordinates and momenta. The commutation relations for the momenta can
be determined only after knowing their functional dependence on coordinates and
velocities.
Thus these commutation relations, as well as the differential calculus on
, depend on the initial choice of Lagrangian. We obtain the
deformed Hamilton's equations of motion and the deformed Poisson brackets, and
their definitions also depend on our initial choice of Lagrangian. We
illustrate these ideas for two sample Lagrangians. The first system we examine
corresponds to that of a nonrelativistic particle in a scalar potential. The
other Lagrangian we consider is first order in time derivative
A burst search for gravitational waves from binary black holes
Compact binary coalescence (CBC) is one of the most promising sources of
gravitational waves. These sources are usually searched for with matched
filters which require accurate calculation of the GW waveforms and generation
of large template banks. We present a complementary search technique based on
algorithms used in un-modeled searches. Initially designed for detection of
un-modeled bursts, which can span a very large set of waveform morphologies,
the search algorithm presented here is constrained for targeted detection of
the smaller subset of CBC signals. The constraint is based on the assumption of
elliptical polarisation for signals received at the detector. We expect that
the algorithm is sensitive to CBC signals in a wide range of masses, mass
ratios, and spin parameters. In preparation for the analysis of data from the
fifth LIGO-Virgo science run (S5), we performed preliminary studies of the
algorithm on test data. We present the sensitivity of the search to different
types of simulated CBC waveforms. Also, we discuss how to extend the results of
the test run into a search over all of the current LIGO-Virgo data set.Comment: 12 pages, 4 figures, 2 tables, submitted for publication in CQG in
the special issue for the conference proceedings of GWDAW13; corrected some
typos, addressed some minor reviewer comments one section restructured and
references updated and correcte
Networks of gravitational wave detectors and three figures of merit
This paper develops a general framework for studying the effectiveness of
networks of interferometric gravitational wave detectors and then uses it to
show that enlarging the existing LIGO-VIRGO network with one or more planned or
proposed detectors in Japan (LCGT), Australia, and India brings major benefits,
including much larger detection rate increases than previously thought... I
show that there is a universal probability distribution function (pdf) for
detected SNR values, which implies that the most likely SNR value of the first
detected event will be 1.26 times the search threshold. For binary systems, I
also derive the universal pdf for detected values of the orbital inclination,
taking into account the Malmquist bias; this implies that the number of
gamma-ray bursts associated with detected binary coalescences should be 3.4
times larger than expected from just the beaming fraction of the gamma burst.
Using network antenna patterns, I propose three figures of merit that
characterize the relative performance of different networks... Adding {\em any}
new site to the planned LIGO-VIRGO network can dramatically increase, by
factors of 2 to 4, the detected event rate by allowing coherent data analysis
to reduce the spurious instrumental coincident background. Moving one of the
LIGO detectors to Australia additionally improves direction-finding by a factor
of 4 or more. Adding LCGT to the original LIGO-VIRGO network not only improves
direction-finding but will further increase the detection rate over the
extra-site gain by factors of almost 2, partly by improving the network duty
cycle... Enlarged advanced networks could look forward to detecting three to
four hundred neutron star binary coalescences per year.Comment: 38 pages, 7 figures, 2 tables. Accepted for publication in Classical
and Quantum Gravit
A comparison of methods for gravitational wave burst searches from LIGO and Virgo
The search procedure for burst gravitational waves has been studied using 24
hours of simulated data in a network of three interferometers (Hanford 4-km,
Livingston 4-km and Virgo 3-km are the example interferometers). Several
methods to detect burst events developed in the LIGO Scientific Collaboration
(LSC) and Virgo collaboration have been studied and compared. We have performed
coincidence analysis of the triggers obtained in the different interferometers
with and without simulated signals added to the data. The benefits of having
multiple interferometers of similar sensitivity are demonstrated by comparing
the detection performance of the joint coincidence analysis with LSC and Virgo
only burst searches. Adding Virgo to the LIGO detector network can increase by
50% the detection efficiency for this search. Another advantage of a joint
LIGO-Virgo network is the ability to reconstruct the source sky position. The
reconstruction accuracy depends on the timing measurement accuracy of the
events in each interferometer, and is displayed in this paper with a fixed
source position example.Comment: LIGO-Virgo working group submitted to PR
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