Conformal mechanics inspired by extremal black holes in d=4
  A canonical transformation which relates the model of a massive relativistic particle moving near the horizon of an extremal black hole in four dimensions and the conventional conformal mechanics is constructed in two different ways. The first approach makes use of the action-angle variables in the angular sector. The second scheme relies upon integrability of the system in the sense of Liouville. 
Anton Galajinsky and Armen Nersessian
hep-th gr-qc