Quantum Computation with Harmonic Oscillators
  By encoding a qudit in a harmonic oscillator and investigating the infinite limit, we give an entirely new realization of continuous-variable quantum computation. The generalized Pauli group is generated by number and phase operators for harmonic oscillators. We describe a physical realization in terms of modes in a microwave cavity, coupled via a standard Kerr nonlinearity. 
Stephen D. Bartlett, Barry C. Sanders, Benjamin T. H. Varcoe and   Hubert de Guise