[1] Univ Technol Sydney, Fac Engn & Informat Technol, Ctr Quantum Computat & Intelligent Syst, Broadway, NSW 2007, Australia
[2] Univ Illinois, Dept Comp Sci, Chicago, IL 60607 USA
[3] Queens Univ Belfast, Sch Elect Elect Engn & Comp Sci, Belfast BT7 1NN, Antrim, North Ireland