Szegő Kernel and Symplectic Aspects of Spectral Transform for Extended Spaces of Rational Matrices

We revisit the symplectic aspects of the spectral transform for matrix-valued rational functions with simple poles. We construct eigenvectors of such matrices in terms of the Szegő kernel on the spectral curve. Using variational formulas for the Szegő kernel, we construct a new system of action-angl...

Full description

Saved in:
Bibliographic Details
Published in:Symmetry, Integrability and Geometry: Methods and Applications
Date:2023
Main Authors: Bertola, Marco, Korotkin, Dmitry, Sasani, Ramtin
Format: Article
Language:English
Published: Інститут математики НАН України 2023
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/212027
Tags: Add Tag
No Tags, Be the first to tag this record!
Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Szegő Kernel and Symplectic Aspects of Spectral Transform for Extended Spaces of Rational Matrices. Marco Bertola, Dmitry Korotkin and Ramtin Sasani. SIGMA 19 (2023), 104, 22 pages

Institution

Digital Library of Periodicals of National Academy of Sciences of Ukraine
Description
Summary:We revisit the symplectic aspects of the spectral transform for matrix-valued rational functions with simple poles. We construct eigenvectors of such matrices in terms of the Szegő kernel on the spectral curve. Using variational formulas for the Szegő kernel, we construct a new system of action-angle variables for the canonical symplectic form on the space of such functions. Comparison with previously known action-angle variables shows that the vector of Riemann constants is the gradient of some function on the moduli space of spectral curves; this function is found in the case of matrix dimension 2, when the spectral curve is hyperelliptic.
ISSN:1815-0659