Classical r-matrix structure for elliptic Ruijsenaars chain and 1+1 field analogue of Ruijsenaars-Schneider model
D. Murinov, A. Zotov
TL;DR
This work develops a comprehensive classical $r$-matrix framework for the periodic elliptic Ruijsenaars chain and its 1+1 field analogue, establishing Liouville integrability via explicit Poisson brackets of the monodromy and demonstrating how the chain reduces to the elliptic Calogero–Moser system in the non-relativistic limit. It then extends the construction to field theories, formulating 1+1 Ruijsenaars–Schneider and Calogero–Moser field theories with Zakharov–Shabat pairs and Maillet-type non-ultralocal $r$-matrices, and proves that the non-relativistic limit reproduces the well-known Maillet brackets. The paper provides detailed derivations of the finite-chain $r$-matrix relations, the field-theoretic $r$-matrices, and their limits, supported by Appendices on elliptic functions and the NKSR formulation. Overall, the results illuminate the link between discrete integrable chains and their continuous field limits, clarifying how non-ultralocality arises and is preserved under canonical limits.
Abstract
The classical dynamical $r$-matrix structure for the periodic elliptic Ruijsenaars chain is described. The Poisson brackets for the monodromy matrix are calculated as well, thus providing Liouville integrability of the model. Next, we study its continuous non-relativistic limit and reproduce the Maillet type non-ultralocal $r$-matrix structure for the field analogue of the elliptic Calogero-Moser model.
