Stacked Qubit Coupling Structure for Control Signal Isolation
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Solution Overview
Problem
Existing quantum bit devices face issues with control signal leakage and crosstalk between quantum bits due to the propagation of control signals through the base material, affecting the integrity of quantum operations.
Innovation Solution
The quantum bit device incorporates a connection substrate with a coupled line that forms capacitive coupling between quantum bits, separated by a ground electrode, which blocks control signal propagation and suppresses leakage, allowing for increased capacitive coupling and quantum operation processing capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control signals are transmitted through the base material to adjacent quantum bits, then quantum operations can be performed, but control signal leakage and crosstalk occur
Solution Approach 1:
The patent divides the device into separate functional layers: a quantum bit substrate for housing quantum bits and control ports, and a connection substrate for forming coupled lines. This segmentation isolates the control signal transmission path from the quantum bit arrangement, preventing leakage while maintaining operational capability.
Solution Approach 2:
The connection substrate acts as an intermediary between the quantum bit substrate and the external control signals. It receives control signals through control ports and transmits them via coupled lines without allowing direct propagation through the base material, thus preventing crosstalk while enabling quantum operations.
2Adaptability or versatility
If quantum bits are connected via coupled lines on the same substrate, then capacitive coupling is formed, but control signals leak to adjacent quantum bits
Solution Approach 1:
The patent transitions from a planar two-dimensional substrate to a three-dimensional stacked architecture with multiple substrates. The quantum bit substrate and connection substrate are positioned at different vertical levels, allowing coupled lines to form capacitive coupling between quantum bits while control signals are routed through dedicated paths that avoid leakage to adjacent quantum bits.
3Measurement precision
If control ports are provided immediately below quantum bits, then precise control is achieved, but control signal propagation through base material causes crosstalk
Solution Approach 1:
The patent extracts the control signal transmission function from the base material and relocates it to the connection substrate. Control ports remain positioned below quantum bits for precise control, but the signal transmission path is separated onto a dedicated substrate layer, eliminating the crosstalk caused by propagation through the base material.
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 configuration effectively suppresses control signal leakage, enhances capacitive coupling, and increases the number of two-qubit gates, thereby improving the quantum operation processing capability of the device.
Implementation Method 1
a ground electrode extending between the first quantum bit and the second quantum bit
Implementation Method 2
a first coupled line that forms capacitive coupling between the first quantum bit and the second quantum bit
Data Source
AI summary
A quantum bit device includes: a first quantum bit substrate including a first quantum bit, a second quantum bit, and a ground electrode extending between the first quantum bit and the second quantum bit; and a connection substrate including a first coupled line that forms capacitive coupling between the first quantum bit and the second quantum bit.