Superconducting Quantum Circuit Modeling via Lumped-Element Approximation
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Solution Overview
Problem
Current modeling techniques for superconducting quantum circuit systems are limited by slow simulation times, low accuracy, and lack of transparency, particularly for complex systems, and often rely on costly multiport impedance simulations that are difficult to calibrate.
Innovation Solution
A computer-implemented modeling tool using electrostatic capacitance extraction and lumped-element approximation to generate a system Hamiltonian, allowing for fast and accurate simulations that capture linear and nonlinear modes, and provide a clear representation of the circuit for design improvements, while reducing the need for full-wave electromagnetics solvers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiport impedance simulations using full-wave electromagnetics solvers are used, then measurement accuracy can be achieved, but simulation time and computational cost increase significantly
Solution Approach 1:
The patent segments the complex full-wave electromagnetics simulation into two distinct parts: (1) a one-time full-wave simulation to extract multiport impedance parameters, and (2) repeated efficient circuit simulations using the extracted parameters. This segmentation allows the computationally intensive full-wave simulation to be performed only once, while subsequent simulations use the pre-extracted parameters for rapid results.
Solution Approach 2:
The patent performs preliminary extraction of multiport impedance parameters from full-wave electromagnetics simulations before conducting the actual circuit simulations. By pre-computing and storing the impedance parameters (S-parameters, Y-parameters, or Z-parameters), the system eliminates the need to run full-wave simulations repeatedly, significantly reducing subsequent simulation times while maintaining accuracy.
2Measurement precision
If detailed full-wave electromagnetics simulations are performed, then accurate results are obtained, but the complexity and computational resources required increase
Solution Approach 1:
The patent extracts the essential electromagnetic characteristics (multiport impedance parameters) from the complex full-wave simulation and separates them from the subsequent circuit analysis. By taking out only the necessary impedance parameters and representing them in simplified circuit models, the system maintains simulation accuracy while dramatically reducing the complexity of repeated analyses.
Solution Approach 2:
The patent creates simplified circuit model copies (equivalent circuits) that replicate the electromagnetic behavior of the original complex structures. These circuit models use standard electrical components with parameters extracted from full-wave simulations, providing an accurate but computationally efficient representation that is much simpler to analyze repeatedly.
3Reliability
If conventional simulation methods are used, then comprehensive system behavior is captured, but the speed and efficiency of design iteration are reduced
Solution Approach 1:
The patent divides the simulation process into a comprehensive initial full-wave simulation phase that captures all electromagnetic effects, followed by efficient circuit simulation phases that iterate rapidly on design parameters. This segmentation ensures comprehensive behavior capture in the initial phase while enabling fast iteration in subsequent phases.
Solution Approach 2:
The patent performs preliminary extraction of comprehensive electromagnetic characteristics including multiport impedance, coupling effects, and resonant modes before design iteration begins. This preliminary action stores all necessary system behavior data in advance, allowing rapid exploration of design variations without repeating comprehensive full-wave simulations.
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
This approach enables faster and more accurate simulations of superconducting quantum circuit chips, providing physically meaningful parameters that can be calibrated with measurements, and offering insights into design enhancements, thus improving the efficiency and accuracy of quantum computing systems.
Implementation Method 1
The superconducting qubit devices can be implemented, for example, using Josephson-junction devices
Data Source
AI summary
In a general aspect, a superconducting quantum circuit system is modeled. In some aspects, a graph representing a quantum circuit system is generated. The graph includes vertices and edges; the edges represent circuit elements of the quantum circuit system, and the vertices represent physical connections between the circuit elements. Inverse inductances, conductances, capacitances, and junction inverse inductances are assigned to respective edges of the graph based on a lumped-element approximation of the quantum circuit system. A coordinate system is determined based on the graph, and a matrix representation of the system is determined based on the coordinate system. A Hamiltonian for the quantum circuit system is determined using the matrix representation, and the quantum circuit system is simulated based on the Hamiltonian.