An 8-bit carry look-ahead adder with 150 ps latency and sub-microwatt   power dissipation at 10 GHz
  Reciprocal Quantum Logic combines the speed and power-efficiency of single-flux quantum superconductor devices with design features that are similar to CMOS. We have demonstrated an 8-bit carry look-ahead adder in the technology using combinational gates with fanout of four and non-local interconnect. Measured power dissipation of the fully active circuit is only 510 nW at 6.2GHz. Latency is only 150 ps at a clock rate of 10GHz. 
Anna Y. Herr, Quentin P. Herr, Oliver T. Oberg, Ofer Naaman, John X.   Przybysz, Pavel Borodulin, and Steven B. Shauck
quant-ph cond-mat.supr-con