论文标题
可逆的Fluxon逻辑,具有优化的CNOT门组件
Reversible Fluxon Logic with optimized CNOT gate components
论文作者
论文摘要
可逆的逻辑门以前是在超导电路中作为绝热可逆门实现的,该门以足够缓慢的时钟供电。相比之下,我们正在研究弹道可逆的大门,其中磁通量可以编码信息并为大门供电。除了输入磁通量的能量外,没有对栅极应用的功率,并且两个可能的磁通极性代表位状态。磁通子几乎从惯性持续速度移动的未阻尼长的约瑟夫森连接(LJJS)形成了大门的输入和输出通道。 LJJS通过电路界面连接在大门中,这些界面旨在使用局部模式的临时激发,允许弹道散射到输出输出状态。谐振散射的持续时间决定了门的运行时间,约有几个约瑟夫森等离子体周期。由于磁通剂与局部模式之间的连贯转换,弹道门的效率可能非常有效:在我们的模拟中,仅在栅极运行中只有几%的Fluxon能量消失了。弹道可逆的门可以与其他非焊接栅极电路结合使用,以扩展栅极功能的范围。在这里,我们描述了如何将CNOT构建为包括IDSN(IDSN-ELSE-SAME-GIVES-NOT)和存储和发布(SNL)门的结构。 IDSN是一个2位弹道门,我们用同等的1位电路来描述和分析。 SNL是一个时钟门,允许存储位,并在位于位依赖的输出路径上的Fluxon的时钟启动。在CNOT中,SNL门为输入IDSN门提供了必要的路由和Fluxon同步。
Reversible logic gates were previously implemented in superconducting circuits as adiabatic-reversible gates, which are powered with a sufficiently slow clock. In contrast, we are studying ballistic-reversible gates, where fluxons serve to both encode the information and power the gates. No power is applied to the gate apart from the energy of the input fluxons, and the two possible flux polarities represent the bit states. Undamped long Josephson junctions (LJJs), where fluxons move at practically constant speed from inertia, form the input and output channels of the gates. LJJs are connected in the gates by circuit interfaces, which are designed to allow the ballistic scattering from input to output fluxon states, using the temporary excitation of a localized mode. The duration of the resonant scattering determines the operation time of the gate, approximately a few Josephson plasma periods. Due to the coherent conversions between fluxon and localized modes the ballistic gates can be very efficient: in our simulations only a few percent of the fluxon's energy are dissipated in the gate operation. Ballistic-reversible gates can be combined with other, non-ballistic gate circuits to extend the range of gate functionalities. Here we describe how the CNOT can be built as a structure that includes the IDSN (Identity-else-Same-gives-NOT) and Store-and-Launch (SNL) gates. The IDSN is a 2-bit ballistic gate, which we describe and analyze in terms of equivalent 1-bit circuits. The SNL is a clocking gate, that allows the storage of a bit and the clocked launch of a fluxon on a bit-state dependent output path. In the CNOT the SNL gates provide the necessary routing and fluxon synchronization for the input to the IDSN gate.