Applications of the group SU(1,1) for quantum computation and tomography
  This paper collects miscellaneous results about the group SU(1,1) that are helpful in applications in quantum optics. Moreover, we derive two new results, the first is about the approximability of SU(1,1) elements by a finite set of elementary gates, and the second is about the regularization of group identities for tomographic purposes. 
G. Chiribella, G. M. D'Ariano, and P. Perinotti