Quantum Charge Parametron Circuit for Adiabatic Low-Energy Switching

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Solution Overview

Problem

Current superconducting computing technologies, particularly those based on Josephson junctions, face challenges in reducing energy consumption for switching events, with adiabatic quantum flux parametron circuits showing promise but lacking practical implementation of adiabatic quantum charge parametron circuits using quantum phase slip junctions.

Innovation Solution

A quantum charge parametron circuit is designed with two quantum phase-slip junctions coupled through a load capacitor, forming charge islands, and adjusted capacitances to achieve adiabatic switching at thermal energy levels, enabling reversible computing with lower energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If Josephson junction-based circuits are used for superconducting computing, then the circuit can perform logic operations, but the energy consumption per switching event is high (on the order of ICΦ0)

Engineering Contradiction:

Improveenergy consumption per switching eventVSAvoidswitching speed

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent changes the operating parameters by using adiabatic switching instead of rapid switching, and by using quantum phase slip junctions with different critical voltage characteristics. This allows the circuit to operate at lower energy per switching event (near kBT) while maintaining computational functionality through reversible logic operations.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs periodic excitation signals to drive the quantum phase slip junctions through their switching transitions. This periodic action enables controlled, reversible switching between logic states with minimal energy dissipation, achieving adiabatic operation where the system remains near equilibrium throughout the transition.

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If adiabatic quantum flux parametron circuits are used, then energy consumption is reduced to near thermal energy levels, but practical implementation of adiabatic quantum charge parametron circuits using quantum phase slip junctions is lacking

Engineering Contradiction:

Improveswitching energyVSAvoidpractical implementation

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent substitutes the flux-based quantum parametron mechanism with a charge-based mechanism using quantum phase slip junctions. This substitution replaces the Josephson junction's flux tunneling with the QPSJ's charge tunneling, enabling adiabatic operation in the charge domain while maintaining the dual-well potential structure necessary for reversible computing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent adjusts the capacitance values in the QPSJ circuit to achieve the desired adiabatic switching characteristics. By carefully selecting the load capacitor and junction capacitor values, the circuit achieves switching energies near kBT while maintaining stable logic states through the dual-well potential landscape.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If quantum phase slip junctions are used with proper DC and RF operation, then lower energy per operation is achieved, but practical implementation has been relatively challenging

Engineering Contradiction:

Improveenergy per operationVSAvoidimplementation complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent divides the QPSJ circuit into distinct functional components: the quantum phase slip junctions for switching, the load capacitor for energy storage and logic state definition, and the excitation voltage source for driving transitions. This segmentation allows each component to be optimized independently while simplifying the overall implementation and control of the adiabatic logic circuit.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The quantum charge parametron circuit operates at switching energies near thermal energy levels, offering faster logic operations and lower energy consumption compared to traditional Josephson junction-based circuits, facilitating adiabatic logic and reversible computing.

Implementation Method 1

QPSJs are duals of JJs based on charge-flux duality. QPSJ based structures may also serve as a potential circuit element in applications in superconducting electronics and quantum information processing

Methodology Applied

Scientific EffectQuantum phase-slip: Josephson Effect

Implementation Method 2

a load capacitor; two quantum phase-slip junctions (QPSJs) coupled to each other through the load capacitor so as to define two charge islands

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10879906B2Quantum phase slip junction based adiabatic logic circuits and applications of same

Publication Date: 2020.12.29 AUBURN UNIVERSITY

AI summary

A quantum charge parametron (QCP) includes a load capacitor; two quantum phase-slip junctions (QPSJs) coupled to each other through the load capacitor so as to define two charge islands, each charge island being located between the load capacitor and a respective one of the two QPSJs; at least one input voltage source coupled to the two QPSJs so that the two QPSJs, the load capacitor and the at least one input voltage source define a loop; and an excitation voltage source coupled to the two charge islands through first and second capacitors, respectively.