Rational Ruijs']jsenaars-Schneider model with cosmological constant

The Ruijsenaars-Schneider models are integrable dynamical realizations of the Poincar & eacute; group in 1 + 1 dimensions, which reduce to the Calogero and Sutherland systems in the nonrelativistic limit. In this work, a possibility to construct a one-parameter deformation of the Ruijsenaars-Schneider models by uplifting the Poincar & eacute; algebra in 1 + 1 dimensions to the anti de Sitter algebra is studied. It is shown that amendments including a cosmological constant are feasible for the rational variant, while the hyperbolic and trigonometric systems are ruled out by our analysis. The issue of integrability of the deformed rational model is discussed in some detail. A complete proof of integrability remains a challenge.