4,711 research outputs found

### Integrability and duality in two-dimensional QCD

We consider bosonized $QCD_2$, 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 $S$-matrix of
$\Complex P^{n-1}$ model, and compute a non-trivial phase factor in the
relation between the $S$-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

### Operator solutions of two-dimensional chiral gauge theories

The exact operator solutions of two-dimensional anomaly-free chiral abelian
gauge theories are obtained. We show that anomaly-cancellation conditions arise
as consistency requirements of these solutions. For a certain class of flavour
symmetries, fermion condensates are constructed. These are shown to violate the
fermion-number conservation rule. The models are extended to include massive
fermions. We propose a bosonised lagrangian for the massive theory and verify
that it complies with the Gupta-Bleuler condition.Comment: 14 pages, latex fil

### Loop scattering in two-dimensional QCD

Using the integrability conditions that we recently obtained in QCD$_2$ 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

### 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

### Gravitational Interactions of integrable models

We couple non-linear $\sigma$-models to Liouville gravity, showing that
integrability properties of symmetric space models still hold for the matter
sector. Using similar arguments for the fermionic counterpart, namely
Gross--Neveu-type models, we verify that such conclusions must also hold for
them, as recently suggested.Comment: 8 pages, final version to appear in Physics Letters B Revised
version, with misprints corrected and some references adde

### An Extensive Search for Overtones in Schwarzschild Black Holes

In this paper we show that with standard methods it is possible to obtain
highly precise results for QNMs. In particular, secondary modes are obtained by
numerical integration. We compare several results making a detailed analysis.Comment: 2 figures, revtex4 use

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