  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.
