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M. V. Gallas

Publications and source records attributed to M. V. Gallas.

5 recordsLinked to original sources

Solitonic Integrable Perturbations of Parafermionic Theories

The quantum integrability of a class of massive perturbations of the parafermionic conformal field theories associated to compact Lie groups is established by showing that they have quantum conserved densities of scale dimension 2 and 3. These theories are integrable for any value of a continuous vector coupling constant, and they generalize the perturbation of the minimal parafermionic models by their first thermal operator. The classical equations-of-motion of these perturbed theories are the non-abelian affine Toda equations which admit (charged) soliton solutions whose semi-classical quantization is expected to permit the identification of the exact S-matrix of the theory.

hep-th↗

The Symmetric Space and Homogeneous sine-Gordon Theories

Two series of integrable theories are constructed which have soliton solutions and can be thought of as generalizations of the sine-Gordon theory. They exhibit internal symmetries and can be described as gauged WZW theories with a potential term. The spectrum of massive states is determined.

hep-th↗

Integrable Systems and W-Algebras

The basic concepts underlying our analysis of {\it W-algebras} as extended symmetries of integrable systems are summarized. The construction starts from the second hamiltonian structure of ``Generalized Drinfel'd-Sokolov'' hierarchies, and its correspondence with the $A_1$-embeddings is established, providing a rather simple and general scheme.

hep-th↗

W-Algebras from Soliton Equations and Heisenberg Subalgebras

We derive sufficient conditions under which the ``second'' Hamiltonian structure of a class of generalized KdV-hierarchies defines one of the classical $\cal W$-algebras obtained through Drinfel'd-Sokolov Hamiltonian reduction. These integrable hierarchies are associated to the Heisenberg subalgebras of an untwisted affine Kac-Moody algebra. When the principal Heisenberg subalgebra is chosen, the well known connection between the Hamiltonian structure of the generalized Drinfel'd-Sokolov hierarchies - the Gel'fand-Dickey algebras - and the $\cal W$-algebras associated to the Casimir invariants of a Lie algebra is recovered. After carefully discussing the relations between the embeddings of $A_1=sl(2,{\Bbb C})$ into a simple Lie algebra $g$ and the elements of the Heisenberg subalgebras of $g^{(1)}$, we identify the class of $\cal W$-algebras that can be defined in this way. For $A_n$, this class only includes those associated to the embeddings labelled by partitions of the form $n+1= k(m) + q(1)$ and $n+1= k(m+1) + k(m) + q(1)$.

hep-th↗