Differential Qubit Chip Coupling for Package Mode Noise Immunity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Scaling up superconducting quantum processors by coupling multiple qubit chips is challenging due to the introduction of additional noise channels and unwanted exchange interactions, which result in correlated gate errors.
Innovation Solution
The use of differential coupling structures, including a differential coupling bus with tunable couplers, to couple quantum bit chips and reduce noise immunity from package modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple quantum bit chips are coupled to scale up quantum processors, then the number of qubits increases, but noise channels and unwanted exchange interactions increase causing correlated gate errors
Solution Approach 1:
The quantum processor is divided into multiple separate quantum bit chips, each containing a subset of qubits. These chips are individually fabricated and then coupled together through an interposer with differential coupling structures. This segmentation allows scaling of qubit count while isolating noise sources to individual chips, preventing system-wide noise propagation.
Solution Approach 2:
An interposer with differential coupling bus structures serves as an intermediary between quantum bit chips. The differential coupling structures act as noise-immune transmission channels that mediate interactions between qubits on different chips while rejecting common-mode noise and unwanted package modes, thus enabling scalable coupling without proportional noise increase.
2Manufacturing precision
If quantum bit chips are individually fabricated and packaged, then manufacturing yield improves and defect screening becomes easier, but coupling between chips introduces noise from package modes
Solution Approach 1:
The quantum processor is divided into multiple separately fabricable quantum bit chips that can be individually packaged and screened for defects. This segmentation maintains manufacturing precision benefits while the differential coupling structures on the interposer subsequently address the noise issue by providing noise-immune inter-chip connections.
Solution Approach 2:
The interposer with differential coupling structures serves as an intermediary that connects individually packaged quantum bit chips. The differential coupling bus provides noise-immune transmission that eliminates package mode noise, allowing the system to retain the manufacturing advantages of individual chip fabrication and packaging.
3Object-affected harmful factors
If differential coupling structures are used to couple quantum bit chips, then immunity to package mode noise is achieved, but device complexity increases
Solution Approach 1:
The interposer with differential coupling structures serves multiple functions simultaneously: it provides noise-immune coupling between chips, enables scalable qubit connectivity, and maintains signal integrity across multiple frequency ranges. This multi-functionality justifies the added complexity by consolidating several requirements into a single integrated solution.
Solution Approach 2:
The differential coupling structures on the interposer act as specialized intermediaries that provide noise-immune transmission for quantum signals between chips. While these structures add complexity compared to simple wiring, they enable reliable scaling by eliminating package mode noise, making them essential rather than optional components for modular quantum processors.
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 provides immunity to noise from package modes, enabling robust chip-to-chip and qubit-qubit coupling, which is essential for high-fidelity two-qubit gate operations in large-scale quantum processors.
Implementation Method 1
The differential coupling bus comprises a first electrical path which capacitively couples the first pad and the third pad, and a second electrical path which capacitively couples the third pad and the fourth pad
Implementation Method 2
The tunable coupler is configured to control interactions between the first quantum bit and the second quantum bit
Data Source
AI summary
A package structure comprises a first quantum bit chip and a second quantum bit chip bonded to an interposer, and a differential coupling bus. The differential coupling bus is configured to differentially couple the first quantum bit chip and the second quantum bit chip at least in part through differential transmission lines disposed on the interposer.