QPSJ Superconducting Logic Cells Using Quantized Current Pulses
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Solution Overview
Problem
The implementation of quantum phase-slip junctions (QPSJs) in superconducting electronics has been challenging due to difficulties in demonstrating practical DC and RF operation, and there is a lack of platforms to identify potential applications of QPSJs in electronic circuits.
Innovation Solution
A new logic family based on current pulses with quantized area, using QPSJs, is developed, along with complementary quantum logic (CQL) that incorporates QPSJs and Josephson junctions, employing a SPICE model to simulate and demonstrate operation, forming hybrid circuits that utilize charge and flux interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If QPSJs are implemented in superconducting electronics, then new logic operations with reduced power dissipation can be achieved, but difficulties in demonstrating practical DC and RF operation and lack of application platforms prevent successful implementation
Solution Approach 1:
The patent introduces a SPICE simulation model as an intermediary platform to bridge the gap between theoretical QPSJ concepts and practical implementation. This virtual platform allows researchers to demonstrate DC and RF operation, test logic circuits, and validate designs before physical fabrication, thereby resolving the reliability demonstration challenge while maintaining low power dissipation benefits
Solution Approach 2:
The patent creates a virtual copy of QPSJ devices through SPICE modeling, enabling the demonstration of practical operation and logic applications without requiring physical device fabrication. This copying approach allows comprehensive testing and validation of QPSJ-based logic circuits while avoiding the complexities of physical implementation
2Productivity
If QPSJ-based logic circuits are developed, then efficient logic operations with reduced power dissipation can be achieved, but the complexity of establishing practical operation frameworks and application platforms increases
Solution Approach 1:
The SPICE model serves as an intermediary that simplifies the complex task of establishing practical QPSJ operation frameworks. By providing a virtual testing environment, it enables efficient logic operation development without requiring complex physical device setups, thus improving productivity while managing complexity
Solution Approach 2:
The patent segments the development process into distinct phases: first establishing the SPICE model for basic QPSJ characterization, then progressively building up to DC operation demonstration, RF operation demonstration, and finally logic circuit applications. This segmentation makes the overall complex task manageable and systematic
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 solution enables the demonstration of QPSJ-based digital logic circuits and CQL, overcoming previous challenges by establishing a practical framework for QPSJ operation and applications, achieving efficient logic operations with reduced power dissipation and simplified design.
Implementation Method 1
Quantum phase-slip is a phenomenon in superconducting systems where the phase difference between two connected superconducting regions changes by 2π with the suppression of the superconducting order parameter to zero. This occurs with quantum tunneling of vortices or fluxons across a narrow superconducting line
Implementation Method 2
A voltage-state type logic was pursued in earlier developments at IBM, for example, which used zero-voltage of JJs during its superconducting state as logical '0' and corresponding non-zero voltage of its normal state as logical '1'
Implementation Method 3
QPSJ is treated in simulation in a fashion similar to a Josephson junction, which has been identified as its dual device based on charge-flux duality
Data Source
AI summary
A superconducting logic cell includes at least one quantum phase-slip junction (QPSJ) for receiving at least one input and responsively providing at least one output, each QPSJ being configured such that when an input voltage of an input voltage pulse exceeds a critical value, a quantized charge of a Cooper electron pair tunnels across said QPSJ as an output, when the input voltage is less than the critical value, no quantized charge of the Cooper electron pair tunnels across said QPSJ as the output, where the presence and absence of the quantized charge in the form of a constant area current pulse in the output form two logic states, and the at least one QPSJ is biased with a bias voltage. The superconducting logic cell further includes at least one Josephson junction (JJ) coupled with the at least one QPSJ to perform one or more logic operations.