Capacitive Qubit Coupling Layout for Crosstalk Suppression
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Solution Overview
Problem
Control signals in quantum bit devices can leak through coupled lines, leading to crosstalk between unintended quantum bits, which affects the integrity of quantum operations.
Innovation Solution
The quantum bit device is configured with a ground electrode extending between quantum bits and a connection substrate featuring capacitive coupling, where the ground electrode overlaps the coupled line to block signal leakage, and capacitive coupling is formed between quantum bits on separate substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If quantum bits are connected via coupled lines to enable multi-qubit operations, then quantum operation processing capability is improved, but control signal leakage to coupled lines occurs causing crosstalk
Solution Approach 1:
A ground electrode is introduced as an intermediary element positioned between the quantum bit and the coupled line. This ground electrode acts as a mediator that redirects control signals away from the coupled line, preventing direct coupling between the control signal and the coupled line that would cause crosstalk.
Solution Approach 2:
The harmful coupling path between the control signal and the coupled line is extracted and eliminated by introducing the ground electrode. The control signal is diverted through the ground electrode to ground potential, removing it from the path that would lead to the coupled line and preventing crosstalk interference.
2Reliability
If ground electrode is introduced to block control signal leakage, then crosstalk is suppressed, but device structure becomes more complex
Solution Approach 1:
The ground electrode is merged with the existing substrate structure, integrating the crosstalk suppression function into the base substrate rather than adding a separate component. This integration minimizes the increase in device complexity while achieving effective control signal isolation.
Solution Approach 2:
The ground electrode serves multiple functions: it provides a reference potential for the quantum bit, acts as a shield to prevent control signal leakage to the coupled line, and establishes a defined electrical boundary. This multi-functionality reduces the need for additional specialized components.
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, increasing the number of connected quantum bits and enhancing quantum operation processing capability by allowing more two-qubit gates to be formed.
Implementation Method 1
a ground electrode extending between the first quantum bit and the second quantum bit... the ground electrode overlaps the coupled line to block signal leakage
Implementation Method 2
a first coupled line that forms capacitive coupling between the first quantum bit and the second quantum bit
Data Source
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AI summary
A quantum bit device (100) includes: a first quantum bit substrate (10) including a first quantum bit (1A), a second quantum bit (1B), and a ground electrode extending between the first quantum bit and the second quantum bit; and a connection substrate (20) including a first coupled line (22) that forms capacitive coupling between the first quantum bit and the second quantum bit.