Simulation of sub-kBT bit-energy operation of adiabatic quantum-flux-parametron logic with low bit-error-rate

Abstract

Adiabatic quantum-flux-parametron (AQFP) logic can achieve high energy-efficiency. The bit energy and bit-error-rate (BER) of AQFP gates with under-damped Josephson junctions were simulated. The results indicate that the bit energy reaches 12 yJ, which is only 20% of the thermal energy at 4.2 K, using unshunted 50-μA junctions and excitation currents with a rise/fall time of 2000 ps. Although the bit energy is extremely small, the bias margin, where the BER is less than 10−23, is approximately ±22%. These results indicate there is no minimum energy limitation for the operation of AQFP gates unless the entropy of the system decreases.