Isospin particle systems on quaternionic projective spaces

We construct the isospin particle system on n-dimensional quaternionic projective spaces in the presence of the Belavin-Polyakov-Schwarz-Tyupkin instanton by the reduction from the free particle on (2n+1)-dimensional complex projective space. Then we add to this system a “quaternionic oscillator potential” and show that this oscillatorlike system is superintegrable. We show that, besides the analogs of quadratic constants of motion of the spherical (Higgs) and CPⁿ oscillators, it possesses the third-order constants of motion, which are functionally independent from the quadratic ones.