Abstract:We study the C n and BC n Ruijsenaars-Schneider(RS) models with interaction potential of trigonometric and rational types. The Lax pairs for these models are constructed and the involutive Hamiltonians are also given. Taking nonrelativistic limit, we also obtain the Lax pairs for the corresponding CalogeroMoser systems. PACS: 02.20.+b, 11.10.Lm, 03.80.+r
I IntroductionRuijsenaars-Schneider(RS) and Calogero-Moser(CM) models as integrable many-body models recently have attracted remarkable attention and have been extensively studied. They describe one-dimensional n-particle system with pairwise interaction. Their importance lies in various fields ranging from lattice models in statistics physics [1,2], the field theory to gauge theory [3,4] Ref. [17], the authors show that for the sl 2 trigonometric RS and CM models exist the same non-dynamical r -matrix structure compared with the usual dynamical ones. On the other hand, similar to Hasegawa's result that A N −1 RS model is related to the Z n Sklyanin algebra, the integrability of CM model can be depicted by sl N Gaudin algebra [18].As for the C n type RS model, commuting difference operators acting on the space of functions on the C 2 type weight space have been constructed by Hasegawa et al in Ref. [16]. Extending that work, the diagonalization of elliptic difference system of that type has been studied by Kikuchi in Ref. [19]. Despite of the fact that the Lax pairs for CM models have *