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Title:
Gaudin Algebras and Piecewise Linear Transformations

Speaker:
Leonid Rybnikov

Abstract:
Gaudin subalgebras form a family of maximal commutative subalgebras in the N-th tensor power of a universal enveloping algebra of a semisimple Lie algebra $\mathfrak{g}$. Aguirre, Felder and Veselov showed, that the closure of this family is naturally parametrized by the moduli space $\bar{M}_{0,N+1}$ of stable rational curves with N+1 marked points. We describe explicitly the commutative subalgebras corresponding to boundary points of $\bar{M}_{0,N+1}$. In particular,that gives rise to a quantization of the "Bending flows" integrable systems of Kapovich and Millson and describes this quantization interms of (some generalization of) Gelfand-Tsetlin bases. In particular, this gives a covering over the real locus of $\bar{M}_{0,N+1}$ whose fiber is naturally identified with the set of integral points of the Gelfand-Tsetlin polytope. We show that in the case $\mathfrak{g}=sl_2$ the corresponding action of the fundamental group on the fiber comes from some natural piecewise linear transformations of the Gelfand-Tsetlin polytope.

Link:
http://scgp.stonybrook.edu/video_portal/video.php?id=151

Workshop:
Simons- Program: Integrability in Modern Theoretical and Mathematical Physics (Fall 2012)