Title of lectures

Loop Groups, R-Matrices and Separation of Variables

Lecturer:

John HARNAD, Concordia University and CRM, Montréal

Outline:

Lecture 1: Review of classical theory of isospectral flow in loop algebras.
Lax equations; spectral curves; linearization of flows. by hyperelliptic integrals.
Examples: Classical Gaudin (Garnier) spin system; periodic Toda lattice, Neumann/Rosoachatius (constrained oscillator) systems;
stationary flows in NLS. (refs. (4), (6), (7))

Lecture 2: Classical R-Matrix theory on loop algebras and groups
Classical Yang--Baxter equations, commuting invariants and Lax equations. Split $R$-matrices and loop algebras. Loop groups and quadratic Poisson brackets. (refs. (1), (2), (3), (6))

Lecture 3 & 4: Separation of variables in Spectral Darboux coordinates.
Rational coadjoint orbits in $\lgl^*(r)_R$. Construction of abelian differentials. Spectral Darboux coordinates. Liouville--Arnold integration and abel map linearization. (refs. (4), (5), (7))

Lecture 5: Introduction to separation of variables in quantum integrable systems.
Quantized Moser systems and separation of variables in $\lgl^*(r)_R$ (refs. (3), (5), (8), (9))

References:

I. Monographs & Reviews (general background on classical and quantum R-Matrices):

Classical:
1) Faddeev, L.D. and Takhtajan, L.A. Hamiltonian Methods in the Theory of Solitons, Springer-Verlag, Berlin (1986).
2) Olshanetsky, M.M., Perelomov, A.M., Reyman, A.G. and Semenov-Tian-Shansky, M.A., Integrable Systems II. Encyclopaedia of Mathematical Sciences Vol. 16, Springer-Verlag, Berlin, Heidelberg, New York (1994).

Classical and Quantum:
3) Korepin, V. E.; Bogoliubov, N. M.; Izergin, A. G. Quantum inverse scattering method and correlation functions. Cambridge Monographs on Mathematical Physics. Cambridge University Press, Cambridge, 1993. Chapts. V-VII.

II. Lecture Notes:

Classical:
4) Harnad, J., "Isospectral Flow and Liouville-Arnold Integration in Loop Algebras", in: Geometric and Quantum Methods in Integrable Systems, Springer Lecture Notes in Physics 424, Pgs 1-42. (ed. G. Helminck, Springer-Verlag, N.Y., Heidelberg, (1993)).

Quantum:
5) Sklyanin, Evgueni K. Separation of variables - new trends. Quantum field theory, integrable models and beyond (Kyoto, 1994). Progr. Theoret. Phys. Suppl. No. 118, 35-60 (1995).

III. Research Papers:

6) Adams, M.R., Harnad, J. and Hurtubise, J., "Dual Moment Maps to Loop Algebras", Lett. Math. Phys. 20, 294-308 (1990).
7) Adams, M.R., Harnad, J. and Hurtubise, J., "Darboux Coordinates and Liouville-Arnold Integration in Loop Algebras", Commun. Math. Phys. 155, 385-413 (1993).
8) Harnad, J. and Winternitz, P., Classical and Quantum Integrable Systems in Lgl(2)^{+*} and Separation of Variables, Commun. Math. Phys. 192, 263-285 (1995).
9) Harnad, J. and Winternitz, P., Harmonics on Hyperspheres, Separation of Variables and the Bethe Ansatz, Lett. Math. Phys. 33, 61-74 (1995).

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