Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501, Japan.
PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
Phys Rev E. 2018 Jan;97(1-1):012124. doi: 10.1103/PhysRevE.97.012124.
According to Landauer's principle, the minimum heat emission required for computing is linked to logical entropy, or logical reversibility. The validity of Landauer's principle has been investigated for several decades and was finally demonstrated in recent experiments by showing that the minimum heat emission is associated with the reduction in logical entropy during a logically irreversible operation. Although the relationship between minimum heat emission and logical reversibility is being revealed, it is not clear how much free energy is required to be dissipated for a logically irreversible operation. In the present study, in order to reveal the connection between logical reversibility and free energy dissipation, we numerically demonstrated logically irreversible protocols using adiabatic superconductor logic. The calculation results of work during the protocol showed that, while the minimum heat emission conforms to Landauer's principle, the free energy dissipation can be arbitrarily reduced by performing the protocol quasistatically. The above results show that logical reversibility is not associated with thermodynamic reversibility, and that heat is not only emitted from logic devices but also absorbed by logic devices. We also formulated the heat emission from adiabatic superconductor logic during a logically irreversible operation at a finite operation speed.
根据兰德auer 原理，计算所需的最小热量排放与逻辑熵或逻辑可逆性有关。几十年来，兰德auer 原理的有效性一直在被研究，最终通过实验证明，最小热量排放与逻辑不可逆操作过程中逻辑熵的减少有关。虽然最小热量排放与逻辑可逆性之间的关系正在被揭示，但对于逻辑不可逆操作需要耗散多少自由能还不清楚。在本研究中，为了揭示逻辑可逆性和自由能耗散之间的联系，我们使用绝热超导逻辑数值演示了逻辑不可逆协议。协议过程中功的计算结果表明，虽然最小热量排放符合兰德auer 原理，但通过准静态执行协议，自由能耗散可以任意降低。上述结果表明，逻辑可逆性与热力学可逆性无关，并且热量不仅从逻辑器件中排放出来，也被逻辑器件吸收。我们还在有限的操作速度下，为绝热超导逻辑在逻辑不可逆操作过程中的热量排放制定了公式。
