Reversible logic circuit, which conserves the thermodynamic entropy during calculation, is an extremely energy-efficient logic circuit. Their energy consumption approaches zero in the quasistatic operation limit if the erasure of the information does not happen. Therefore, the energy consumption can be reduced even lower than the thermal limit k_{B}*T*ln2, known as the Landauer limit [1]. We proposed that the reversible logic gate can be realized based on the adiabatic quantum flux parametron (AQFP) and named it the reversible quantum flux parametron (RQFP) [2][3]. In this presentation, we will show our latest progress in this study. After introducing the operation principle of the RQFP gate, we will discuss the origin of energy consumption in reversible and irreversible logic circuits. We have designed and demonstrated several RQFP logic circuits, including an 8-bit ripple carry adder, 4-to-16 decoder, and flip-flops. Simulation results of the RQFP circuits indicate that their energy consumption is lower than those based on irreversible AQFP logic when the operation frequency is reduced and even lower than the Landauer limit. The perspective of the reversible circuits based on AQFP will be shown.

[1] N. Takeuchi, Y. Yamanashi, N. Yoshikawa, “Reversible logic gate using adiabatic superconducting devices,” Scientific Reports, 4, 6354 (2014).

[2] N. Takeuchi, Y. Yamanashi, N. Yoshikawa, “Reversibility and energy dissipation in adiabatic superconductor logic,” Scientific Reports, 7, 75-1-12 (2017).

[3] R. Landauer, “Irreversibility and Heat Generation in the Computing Process,” IBM J. Res. Develop. 5, 183–191 (1961).

[4] T. Yamae, N. Takeuchi, N. Yoshikawa, “A reversible full adder using adiabatic superconductor logic,” Supercond. Sci. Technol. 32, 035005 (2019).

Keywords: Digital