109 research outputs found
Invariant Differential Operators for Non-Compact Lie Groups: the Sp(n,R) Case
In the present paper we continue the project of systematic construction of
invariant differential operators on the example of the non-compact algebras
sp(n,R), in detail for n=6. Our choice of these algebras is motivated by the
fact that they belong to a narrow class of algebras, which we call 'conformal
Lie algebras', which have very similar properties to the conformal algebras of
Minkowski space-time. We give the main multiplets and the main reduced
multiplets of indecomposable elementary representations for n=6, including the
necessary data for all relevant invariant differential operators. In fact, this
gives by reduction also the cases for n<6, since the main multiplet for fixed n
coincides with one reduced case for n+1.Comment: Latex2e, 27 pages, 8 figures. arXiv admin note: substantial text
overlap with arXiv:0812.2690, arXiv:0812.265
Domains of holomorphy for irreducible unitary representations of simple Lie groups
We classify the domains of holomorphy of all Harish-Chandra modules of
irreducible unitary representations of simple non-compact Lie groups.Comment: revised version, to appear in Invent. math., 14 page
Symmetric spaces of higher rank do not admit differentiable compactifications
Any nonpositively curved symmetric space admits a topological
compactification, namely the Hadamard compactification. For rank one spaces,
this topological compactification can be endowed with a differentiable
structure such that the action of the isometry group is differentiable.
Moreover, the restriction of the action on the boundary leads to a flat model
for some geometry (conformal, CR or quaternionic CR depending of the space).
One can ask whether such a differentiable compactification exists for higher
rank spaces, hopefully leading to some knew geometry to explore. In this paper
we answer negatively.Comment: 13 pages, to appear in Mathematische Annale
The projective translation equation and unramified 2-dimensional flows with rational vector fields
Let X=(x,y). Previously we have found all rational solutions of the
2-dimensional projective translation equation, or PrTE,
(1-z)f(X)=f(f(Xz)(1-z)/z); here f(X)=(u(x,y),v(x,y)) is a pair of two (real or
complex) functions. Solutions of this functional equation are called projective
flows. A vector field of a rational flow is a pair of 2-homogenic rational
functions. On the other hand, only special pairs of 2-homogenic rational
functions give rise to rational flows. In this paper we are interested in all
non-singular (satisfying the boundary condition) and unramified (without
branching points, i.e. single-valued functions in C^2\{union of curves})
projective flows whose vector field is still rational. We prove that, up to
conjugation with 1-homogenic birational plane transformation, these are of 6
types: 1) the identity flow; 2) one flow for each non-negative integer N -
these flows are rational of level N; 3) the level 1 exponential flow, which is
also conjugate to the level 1 tangent flow; 4) the level 3 flow expressable in
terms of Dixonian (equianharmonic) elliptic functions; 5) the level 4 flow
expressable in terms of lemniscatic elliptic functions; 6) the level 6 flow
expressable in terms of Dixonian elliptic functions again. This reveals another
aspect of the PrTE: in the latter four cases this equation is equivalent and
provides a uniform framework to addition formulas for exponential, tangent, or
special elliptic functions (also addition formulas for polynomials and the
logarithm, though the latter appears only in branched flows). Moreover, the
PrTE turns out to have a connection with Polya-Eggenberger urn models. Another
purpose of this study is expository, and we provide the list of open problems
and directions in the theory of PrTE; for example, we define the notion of
quasi-rational projective flows which includes curves of arbitrary genus.Comment: 34 pages, 2 figure
Quantum differential forms
Formalism of differential forms is developed for a variety of Quantum and
noncommutative situations
Fusion and singular vectors in A1{(1)} highest weight cyclic modules
We show how the interplay between the fusion formalism of conformal field
theory and the Knizhnik--Zamolodchikov equation leads to explicit formulae for
the singular vectors in the highest weight representations of A1{(1)}.Comment: 42 page
Special Reduced Multiplets and Minimal Representations for SO(p,q)
Using our previous results on the systematic construction of invariant
differential operators for non-compact semisimple Lie groups we classify the
special reduced multiplets and minimal representations in the case of SO(p,q).Comment: 26 pages, 11 figures, to appear in the Proceedings of the X
International Workshop "Lie Theory and Its Applications in Physics}, (Varna,
Bulgaria, June 2013), "Springer Proceedings in Mathematics and Statistics",
Vol. 11
Hyperkahler sigma models on cotangent bundles of Hermitian symmetric spaces using projective superspace
Kahler manifolds have a natural hyperkahler structure associated with (part
of) their cotangent bundles. Using projective superspace, we construct
four-dimensional N = 2 models on the tangent bundles of some classical
Hermitian symmetric spaces (specifically, the four regular series of
irreducible compact symmetric Kahler manifolds, and their non-compact
versions). A further dualization yields the Kahler potential for the
hyperkahler metric on the cotangent bundle.Comment: 47 pages, typos corrected, version accepted by JHE
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