Increasing fan-in and fan-out of the quantum phase slip junction-based logic gates

Fan-in and fan-out of the quantum phase slip junction (QPSJ)-based two-input AND and OR gates are increased for the first time. For increasing their fan-in, critical voltage, normal and sub-gap resistances, and kinetic inductance of their constituent QPSJs are changed, and only input and buffer QPSJs are added to the gate. The number of elements in the proposed three- and four-input OR and three- and four-input AND gates is 13, 16, 16, and 20, respectively, which are fewer than those in the serial connection method. For increasing the fan-out to two, only the mentioned parameters of the constituent QPSJs are changed and no extra element is added to the gate circuits. Comparing with the existing method which adds extra Josephson Junctions and QPSJs to the gate output, the number of elements in the proposed method is that of the basic two-input gates. For the increased fan-in/fan-out OR gates, the critical margins of the external parameters are 10% and 15% of the input voltage, and the critical junction margins are 30% and 26% respectively, while for the increased fan-in/fan-out AND gates, they are 9% and 12% of the bias voltage and 26% and 23% for the critical junction margins, respectively.

Automated summary

For the first time, the fan-in and fan-out of quantum phase slip junction (QPSJ)-based two-input AND and OR gates are increased. The proposed method has fewer elements and better performance compared to existing methods.