1,690 research outputs found
Non-commutative solitons and strong-weak duality
Some properties of the non-commutative versions of the sine-Gordon model
(NCSG) and the corresponding massive Thirring theories (NCMT) are studied. Our
method relies on the NC extension of integrable models and the master
Lagrangian approach to deal with dual theories. The master Lagrangians turn out
to be the NC versions of the so-called affine Toda model coupled to matter
fields (NCATM) associated to the group GL(2), in which the Toda field belongs
to certain representations of either or corresponding
to the Lechtenfeld et al. (NCSG) or Grisaru-Penati (NCSG) proposals
for the NC versions of the sine-Gordon model, respectively. Besides, the
relevant NCMT models are written for two (four) types of Dirac fields
corresponding to the Moyal product extension of one (two) copy(ies) of the
ordinary massive Thirring model. The NCATM models share the same
one-soliton (real Toda field sector of model 2) exact solutions, which are
found without expansion in the NC parameter for the corresponding Toda
and matter fields describing the strong-weak phases, respectively. The
correspondence NCSG NCMT is promising since it is
expected to hold on the quantum level.Comment: 24 pages, 1 fig., LaTex. Typos in star products of eqs. (3.11)-(3.13)
and footnote 1 were corrected. Version to appear in JHE
A Representation of the Virasoro Algebra via Wigner-Heisenberg Algebraic Technique to Bosonic Systems
Using the Wigner-Heisenberg algebra for bosonic systems in connection with
oscillators we find a new representation for the Virasoro algebra.Comment: Revised version. Revtex, 7 pages, no figures. This work was presented
in the XXII Brazilian National Meeting on Particles and Fields
(October/2001), to appear in Braz. J. of Phys., 33, 1 (2003
Normal ordering and boundary conditions in open bosonic strings
Boundary conditions play a non trivial role in string theory. For instance
the rich structure of D-branes is generated by choosing appropriate
combinations of Dirichlet and Neumann boundary conditions. Furthermore, when an
antisymmetric background is present at the string end-points (corresponding to
mixed boundary conditions) space time becomes non-commutative there.
We show here how to build up normal ordered products for bosonic string
position operators that satisfy both equations of motion and open string
boundary conditions at quantum level. We also calculate the equal time
commutator of these normal ordered products in the presence of antisymmetric
tensor background.Comment: 7 pages no figures, References adde
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