639 research outputs found
On the spectra of the quantized action-variables of the compactified Ruijsenaars-Schneider system
A simple derivation of the spectra of the action-variables of the quantized
compactified Ruijsenaars-Schneider system is presented. The spectra are
obtained by combining Kahler quantization with the identification of the
classical action-variables as a standard toric moment map on the complex
projective space. The result is consistent with the Schrodinger quantization of
the system worked out previously by van Diejen and Vinet.Comment: Based on talk at the workshop CQIS-2011 (Protvino, Russia, January
2011), 12 page
Conserved quantities in non-abelian monopole fields
Van Holten's covariant Hamiltonian framework is used to find conserved
quantities for an isospin-carrying particle in a non-Abelian monopole-like
field. For a Wu-Yang monopole we find the most general scalar potential such
that the combined system admits a conserved Runge-Lenz vector. It generalizes
the fine-tuned inverse-square plus Coulomb potential, found before by McIntosh
and Cisneros, and by Zwanziger, for a charged particle in the field of a Dirac
monopole. Following Feh\'er, the result is interpreted as describing motion in
the asymptotic field of a self-dual Prasad-Sommerfield monopole. In the
effective non-Abelian field for nuclear motion in a diatomic molecule due to
Moody, Shapere and Wilczek, a conserved angular momentum is constructed,
despite the non-conservation of the electric charge. No Runge-Lenz vector has
been found.Comment: 8 pages, RevTex no figures. An error corrected and a new Section
adde
Hamiltonian reductions of free particles under polar actions of compact Lie groups
Classical and quantum Hamiltonian reductions of free geodesic systems of
complete Riemannian manifolds are investigated. The reduced systems are
described under the assumption that the underlying compact symmetry group acts
in a polar manner in the sense that there exist regularly embedded, closed,
connected submanifolds meeting all orbits orthogonally in the configuration
space. Hyperpolar actions on Lie groups and on symmetric spaces lead to
families of integrable systems of spin Calogero-Sutherland type.Comment: 15 pages, minor correction and updated references in v
A Class of W-Algebras with Infinitely Generated Classical Limit
There is a relatively well understood class of deformable W-algebras,
resulting from Drinfeld-Sokolov (DS) type reductions of Kac-Moody algebras,
which are Poisson bracket algebras based on finitely, freely generated rings of
differential polynomials in the classical limit. The purpose of this paper is
to point out the existence of a second class of deformable W-algebras, which in
the classical limit are Poisson bracket algebras carried by infinitely,
nonfreely generated rings of differential polynomials. We present illustrative
examples of coset constructions, orbifold projections, as well as first class
Hamiltonian reductions of DS type W-algebras leading to reduced algebras with
such infinitely generated classical limit. We also show in examples that the
reduced quantum algebras are finitely generated due to quantum corrections
arising upon normal ordering the relations obeyed by the classical generators.
We apply invariant theory to describe the relations and to argue that classical
cosets are infinitely, nonfreely generated in general. As a by-product, we also
explain the origin of the previously constructed and so far unexplained
deformable quantum W(2,4,6) and W(2,3,4,5) algebras.Comment: 39 pages (plain TeX), ITP-SB-93-84, BONN-HE-93-4
Coadjoint orbits of the Virasoro algebra and the global Liouville equation
The classification of the coadjoint orbits of the Virasoro algebra is
reviewed and is then applied to analyze the so-called global Liouville
equation. The review is self-contained, elementary and is tailor-made for the
application. It is well-known that the Liouville equation for a smooth, real
field under periodic boundary condition is a reduction of the SL(2,R)
WZNW model on the cylinder, where the WZNW field g in SL(2,R) is restricted to
be Gauss decomposable. If one drops this restriction, the Hamiltonian reduction
yields, for the field where is a constant,
what we call the global Liouville equation. Corresponding to the winding number
of the SL(2,R) WZNW model there is a topological invariant in the reduced
theory, given by the number of zeros of Q over a period. By the substitution
, the Liouville theory for a smooth is recovered in
the trivial topological sector. The nontrivial topological sectors can be
viewed as singular sectors of the Liouville theory that contain blowing-up
solutions in terms of . Since the global Liouville equation is
conformally invariant, its solutions can be described by explicitly listing
those solutions for which the stress-energy tensor belongs to a set of
representatives of the Virasoro coadjoint orbits chosen by convention. This
direct method permits to study the `coadjoint orbit content' of the topological
sectors as well as the behaviour of the energy in the sectors. The analysis
confirms that the trivial topological sector contains special orbits with
hyperbolic monodromy and shows that the energy is bounded from below in this
sector only.Comment: Plain TEX, 48 pages, final version to appear in IJMP
Extended matrix Gelfand-Dickey hierarchies: reduction to classical Lie algebras
The Drinfeld-Sokolov reduction method has been used to associate with
extensions of the matrix r-KdV system. Reductions of these systems to the fixed
point sets of involutive Poisson maps, implementing reduction of to
classical Lie algebras of type , are here presented. Modifications
corresponding, in the first place to factorisation of the Lax operator, and
then to Wakimoto realisations of the current algebra components of the
factorisation, are also described.Comment: plain TeX, 12 page
Zoological collectings in Albania between 2004 and 2010 by the Hungarian Natural History Museum and the Hungarian Academy of Sciences
The Albanian locality data of zoological collectings carried out by the Hungarian Natural History Museum and theHungarian Academy of Sciences during 30 tours to the Balkans between 2004 and 2010 are enumerated. The localities andmethods of collecting are enumerated in chronological order. Sites are marked on the map of Albania
Chiral extensions of the WZNW phase space, Poisson-Lie symmetries and groupoids
The chiral WZNW symplectic form is inverted in the general case. Thereby a precise relationship between the arbitrary monodromy dependent 2-form appearing in and the exchange r-matrix that governs the Poisson brackets of the group valued chiral fields is established. The exchange r-matrices are shown to satisfy a new dynamical generalization of the classical modified Yang-Baxter (YB) equation and Poisson-Lie (PL) groupoids are constructed that encode this equation analogously as PL groups encode the classical YB equation. For an arbitrary simple Lie group G, exchange r-matrices are found that are in one-to-one correspondence with the possible PL structures on G and admit them as PL symmetries
Non-standard Quantum Group in Toda and WZNW Theories
The basic Poisson brackets in the chira.l sectors of the WZNW theory and its Toda reduction are described in terms of a monodromy dependent r-matrix. In the case of the sl(n) Lie algebras, and only then, this monodromy dependence can be âgauged awayâ. The resulting non-trivial solution of the classical Yang-Baxter equation is the classical limit of the quantum R-matrix of the SL(n) Toda theory found recently by Creminer and Gervais. The deformations of SL(n) and U(sl(n)) defined by this R-matrix are studied in the simplest non-trivial case of n = 3. The multiplicative structure of this deformation of U(sl(3)) can be transformed into that of the standard U_q(sl(3)), but the coproduct is different. Possible generalizations for arbitrary n and applications in conformal field theory and in non-commutative differential geometry are briefly indicated. The Cremmer-Gervais R-matrix is âYang-Baxterizedâ. The resulting spectral parameter dependent R-matrix may give rise to a new series of integrable models
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