3,850 research outputs found
Integrability and duality in two-dimensional QCD
We consider bosonized , and prove that after rewritting the theory in
terms of gauge invariant fields, there exists an integrability condition valid
for the quantum theory as well. Furthermore, performing a duality type
transformation we obtain an appropriate action for the description of the
strong coupling limit, which is still integrable. We also prove that the model
displays a complicated set of constraints, restricting the dynamics of part of
the theory, but which are necessary to maintain the positive metric Hilbert
space.Comment: 31 pages, plain tex prep. CERN-TH.7354/94, July 1994, with
corrections in the text and reference
Exact S matrices and extended supersymmetry
In this revised version we correct some mistakes, realizing the supersymmetry
algebra on the exact S matrix, taking into account several phase factros. We
study the constraint imposed by supersymmetry on the exact -matrix of
model, and compute a non-trivial phase factor in the
relation between the -matrix and one of the supersymmetry generators. We
discuss several features connected with the physical interpretation of the
result. The supersymmetry current is studied in such context as well, and we
find some operators appearing in the conservation equation of the supersymmetry
current that might be connected with such phase factors. The relation with the
literature on the subject is also discussed. hep-th/yymmnnnComment: 12 pages, plain tex, 1 figure in uuencoded file after the tex file,
prep CERN-TH-7106/9
Scale Invariance in a Perturbed Einstein-de Sitter Cosmology
This paper seeks to check the validity of the "apparent fractal conjecture"
(Ribeiro 2001ab: gr-qc/9909093, astro-ph/0104181), which states that the
observed power-law behaviour for the average density of large-scale
distribution of galaxies arises when some observational quantities, selected by
their relevance in average density profile determination, are calculated along
the past light cone. Implementing these conditions in the proposed set of
observational relations profoundly changes the behaviour of many observables in
the standard cosmological models. In particular, the average density becomes
observationally inhomogeneous, even in the spatially homogeneous spacetime of
standard cosmology, change which was already analysed by Ribeiro (1992b, 1993,
1994, 1995: astro-ph/9910145) for a non-perturbed model. Here we derive
observational relations in a perturbed Einstein-de Sitter cosmology by means of
the perturbation scheme proposed by Abdalla and Mohayaee (1999:
astro-ph/9810146), where the scale factor is expanded in power series to yield
perturbative terms. The differential equations derived in this perturbative
context, and other observables necessary in our analysis, are solved
numerically. The results show that our perturbed Einstein-de Sitter cosmology
can be approximately described by a decaying power-law like average density
profile, meaning that the dust distribution of this cosmology has a scaling
behaviour compatible with the power-law profile of the density-distance
correlation observed in the galaxy catalogues. These results show that, in the
context of this work, the apparent fractal conjecture is correct.Comment: 18 pages, 1 figure, LaTeX. Final version (small changes in the figure
plus some references update). Fortran code included with the LaTeX source. To
be published in "Fractals
Current Algebra of Super WZNW Models
We derive the current algebra of supersymmetric principal chiral models with
a Wess-Zumino term. At the critical point one obtains two commuting super
Kac-Moody algebra as expected, but in general there are intertwining fields
connecting both right and left sectors, analogously to the bosonic case.
Moreover, in the present supersymmetric extension we have a quadratic algebra,
rather than an affine Lie algebra, due to the mixing between bosonic and
fermionic fields since the purely fermionic sector displays a Lie algebra as
well.Comment: 13 page
Loop scattering in two-dimensional QCD
Using the integrability conditions that we recently obtained in QCD with
massless fermions, we arrive at a sufficient number of conservation laws to be
able to fix the scattering amplitudes involving a local version of the Wilson
loop operator.Comment: 6 pages, plain tex
Ultra cold neutrons: determination of the electric dipole moment and gravitational corrections via matter wave interferometry
We propose experiments using ultra cold neutrons which can be used to
determine the electric dipole moment of the neutron itself, a well as to test
corrections to gravity as they are foreseen by string theories and Kaluza-Klein
mechanisms.Comment: 3 pages, no figures, reference adde
The Algebra of Non-Local Charges in Non-Linear Sigma Models
We obtain the exact Dirac algebra obeyed by the conserved non-local charges
in bosonic non-linear sigma models. Part of the computation is specialized for
a symmetry group . As it turns out the algebra corresponds to a cubic
deformation of the Kac-Moody algebra. The non-linear terms are computed in
closed form. In each Dirac bracket we only find highest order terms (as
explained in the paper), defining a saturated algebra. We generalize the
results for the presence of a Wess-Zumino term. The algebra is very similar to
the previous one, containing now a calculable correction of order one unit
lower.Comment: 27 pages + figures available via ftp, Plain TeX, IFUSP/P-106
Integrable models: from dynamical solutions to string theory
We review the status of integrable models from the point of view of their
dynamics and integrability conditions. Some integrable models are discussed in
detail. We comment on the use it is made of them in string theory. We also
discuss the Bethe Ansatz solution of the SO(6) symmetric Hamiltonian with SO(6)
boundary.
This work is especially prepared for the seventieth anniversaries of
Andr\'{e} Swieca (in memoriam) and Roland K\"{o}berle.Comment: 24 pages, to appear in Brazilian Journal of Physic
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