128 research outputs found
The Quantum Galilei Group
The quantum Galilei group is defined. The bicrossproduct
structure of and the corresponding Lie algebra is revealed. The
projective representations for the two-dimensional quantum Galilei group are
constructed.Comment: AMSTe
Global Symmetries of Noncommutative Space-time
The global counterpart of infinitesimal symmetries of noncommutative
space-time is discussed.Comment: 7 pages, no figures; minor changes in the bibliography; final version
accepted for publication in Phys. Rev.
New realizations of Lie algebra kappa-deformed Euclidean space
We study Lie algebra -deformed Euclidean space with undeformed
rotation algebra and commuting vectorlike derivatives. Infinitely
many realizations in terms of commuting coordinates are constructed and a
corresponding star product is found for each of them. The -deformed
noncommutative space of the Lie algebra type with undeformed Poincar{\'e}
algebra and with the corresponding deformed coalgebra is constructed in a
unified way.Comment: 30 pages, Latex, accepted for publication in Eur.Phys.J.C, some typos
correcte
Quantum Deformations of Space-Time Symmetries with Mass-Like Deformation Parameter
The difficulties with the measurability of classical space-time distances are
considered. We outline the framework of quantum deformations of D=4 space-time
symmetries with dimensionfull deformation parameter, and present some recent
results.Comment: 4 pages, LaTeX, uses file stwol.sty, to be published in the
Proceedings of XXXII International Rochester Conference in High Energy
Physics (Warsaw, 24.07-31.07 1996
Particle velocity in noncommutative space-time
We investigate a particle velocity in the -Minkowski space-time,
which is one of the realization of a noncommutative space-time. We emphasize
that arrival time analyses by high-energy -rays or neutrinos, which
have been considered as powerful tools to restrict the violation of Lorentz
invariance, are not effective to detect space-time noncommutativity. In
contrast with these examples, we point out a possibility that {\it low-energy
massive particles} play an important role to detect it.Comment: 16 pages, corrected some mistake
On the unitarity of higher-dervative and nonlocal theories
We consider two simple models of higher-derivative and nonlocal quantu
systems.It is shown that, contrary to some claims found in literature, they can
be made unitary.Comment: 8 pages, no figure
Performance Evaluation of Road Traffic Control Using a Fuzzy Cellular Model
In this paper a method is proposed for performance evaluation of road traffic
control systems. The method is designed to be implemented in an on-line
simulation environment, which enables optimisation of adaptive traffic control
strategies. Performance measures are computed using a fuzzy cellular traffic
model, formulated as a hybrid system combining cellular automata and fuzzy
calculus. Experimental results show that the introduced method allows the
performance to be evaluated using imprecise traffic measurements. Moreover, the
fuzzy definitions of performance measures are convenient for uncertainty
determination in traffic control decisions.Comment: The final publication is available at http://www.springerlink.co
Noncommutative Parameters of Quantum Symmetries and Star Products
The star product technique translates the framework of local fields on
noncommutative space-time into nonlocal fields on standard space-time. We
consider the example of fields on - deformed Minkowski space,
transforming under -deformed Poincar\'{e} group with noncommutative
parameters. By extending the star product to the tensor product of functions on
-deformed Minkowski space and -deformed Poincar\'{e} group we
represent the algebra of noncommutative parameters of deformed relativistic
symmetries by functions on classical Poincar\'{e} group.Comment: LaTeX2e, 10 pages. To appear in the Proceedings of XXIII
International Colloquium on Group-Theoretical Methods in Physics, July 31-
August 5, Dubna, Russia". The names of the authors correcte
Transformations of coordinates and Hamiltonian formalism in deformed Special Relativity
We investigate the transformation laws of coordinates in generalizations of
special relativity with two observer-independent scales. The request of
covariance leads to simple formulas if one assumes noncanonical Poisson
brackets, corresponding to noncommuting spacetime coordinates.Comment: 11 pages, plain LaTe
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