Magnetic Flux Bias Circuit for Multiplexed Qubit Control
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Solution Overview
Problem
Controlling a large number of quantum bits in quantum computers is challenging due to the limited number of control lines available, making it difficult to scale up quantum computing systems.
Innovation Solution
A magnetic flux bias circuit is designed with an input signal line, current control lines, and a digital/analog conversion unit using a quantum flux parametron circuit, which converts digital input signals into analog signals to apply magnetic flux to controlled objects, allowing for efficient control with a small number of control lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large number of quantum bits are controlled using separate control lines, then each quantum bit can be independently controlled, but the number of control lines increases proportionally, making the system complex and difficult to scale
Solution Approach 1:
The control system is segmented into multiple banks, where each bank can independently control a subset of quantum bits. This segmentation allows the control functionality to be distributed across fewer physical control lines by time-multiplexing the control signals across different banks.
Solution Approach 2:
The control system dynamically assigns control lines to different quantum bit banks at different time periods. A single control line can be dynamically reconfigured to control different banks sequentially, enabling one control line to effectively control multiple quantum bits through time-division multiplexing.
2Measurement precision
If more control lines are provided to control more quantum bits, then the control precision and individual control capability are maintained, but the physical space and connection requirements increase
Solution Approach 1:
Each control line is designed to be multi-functional, serving multiple quantum bit banks at different time periods. This universality allows the same physical control line to perform multiple control functions sequentially, reducing the total number of control lines needed while maintaining individual control precision for each quantum bit.
Solution Approach 2:
The control system employs periodic time-division multiplexing where control lines are periodically assigned to different banks. Each bank receives dedicated control attention in periodic intervals, ensuring precise control while utilizing the same physical infrastructure repeatedly across different time periods.
3Productivity
If the number of quantum bits is increased beyond the cable limit, then the computing power and quantum system capability are enhanced, but the system becomes inoperable due to insufficient control lines
Solution Approach 1:
The control architecture dynamically reconfigures control line assignments based on which bank needs control at any given time. This dynamic reconfiguration enables the system to operate with far fewer physical control lines than quantum bits by ensuring that control capability is always available when needed, just at different times for different banks.
Solution Approach 2:
A control circuit acting as an intermediary is introduced between the control lines and quantum bit banks. This intermediary manages the time-division multiplexing and bank switching, allowing a small number of control lines to effectively control a large number of quantum bits through intelligent intermediary management.
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 solution enables the control of a large number of quantum bits with a small number of control lines, improving scalability and reducing power consumption while maintaining high-speed operation.
Implementation Method 1
a digital/analog conversion unit converting the input signal into an analog signal using a circuit including a quantum flux parametron circuit
Implementation Method 2
quantum flux parametron circuit
Implementation Method 3
a magnetic flux application unit applying an applied magnetic flux to a controlled object on the basis of the analog signal output
Data Source
AI summary
A magnetic flux bias circuit includes an input signal line to which an input signal indicating an applied magnetic flux using a digital value is input, a first current control line, a second current control line, and a third current control line to which a clock signal according to the input signal is input, a digital/analog conversion unit converting the input signal into an analog signal using a circuit including a quantum flux parametron circuit on the basis of the input signal input to the input signal line and the clock signal input to the first current control line, the second current control line, and the third current control line, and a magnetic flux application unit applying an applied magnetic flux to a controlled object on the basis of the analog signal output from the digital/analog conversion unit.