14,946 research outputs found
Lagrangian formulation for noncommutative nonlinear systems
In this work we use the well known formalism developed by Faddeev and Jackiw
to introduce noncommutativity within two nonlinear systems, the SU(2) Skyrme
and O(3) nonlinear sigma models. The final result is the Lagrangian
formulations for the noncommutative versions of both models. The possibility of
obtaining different noncommutative versions for these nonlinear systems is
demonstrated.Comment: 8 pages. Revex 4.
The Jacobi identity for Dirac-like brackets
For redundant second-class constraints the Dirac brackets cannot be defined
and new brackets must be introduced. We prove here that the Jacobi identity for
the new brackets must hold on the surface of the second-class constraints. In
order to illustrate our proof we work out explicitly the cases of a fractional
spin particle in 2+1 dimensions and the original Brink-Schwarz massless
superparticle in D=10 dimensions in a Lorentz covariant constraints separation.Comment: 14 pages, Latex. Final version to be published in Int. J. Mod. Phys.
Quantum complex scalar fields and noncommutativity
In this work we analyze complex scalar fields using a new framework where the
object of noncommutativity represents independent degrees of
freedom. In a first quantized formalism, and its canonical
momentum are seen as operators living in some Hilbert space.
This structure is compatible with the minimal canonical extension of the
Doplicher-Fredenhagen-Roberts (DFR) algebra and is invariant under an extended
Poincar\'e group of symmetry. In a second quantized formalism perspective, we
present an explicit form for the extended Poincar\'e generators and the same
algebra is generated via generalized Heisenberg relations. We also introduce a
source term and construct the general solution for the complex scalar fields
using the Green's function technique.Comment: 13 pages. Latex. Final version to appear in Physical Review
Clan structure analysis and new physics signals in pp collisions at LHC
The study of possible new physics signals in global event properties in pp
collisions in full phase space and in rapidity intervals accessible at LHC is
presented. The main characteristic is the presence of an elbow structure in
final charged particle MD's in addition to the shoulder observed at lower c.m.
energies.Comment: 9 pages, talk given at Focus on Multiplicity (Bari, Italy, June 2004
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