Multi-Capacitor Qubit Circuit Layout for Scalable Quantum Chips

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Solution Overview

Problem

Existing quantum computing technologies face spatial limitations in designing and laying out quantum circuits due to the structure of qubits with a single grounded capacitor and a superconducting quantum interference device (SQUID) connected in parallel, which restricts the arrangement of other circuit structures and qubit connectivity.

Innovation Solution

A quantum circuit design featuring multiple capacitors, including a first and second capacitor with one end grounded and a first device comprising a first SQUID and a third capacitor connected in parallel, allowing flexible capacitor selection and adjustment of anharmonic parameters, enabling two-dimensional qubit arrangements and larger space for other circuit structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single grounded capacitor and SQUID connected in parallel are used for qubit structure, then the qubit can be prepared on substrate by micro-nano machining technology, but spatial limitations occur that affect design and layout of other circuit structures

Engineering Contradiction:
Improvequbit preparation by micro-nano machiningVSAvoidspace for circuit layout
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The single capacitor is segmented into multiple capacitors (first capacitor, second capacitor, third capacitor) with different grounding configurations. This segmentation allows the qubit structure to maintain manufacturability while reducing the spatial footprint and enabling better circuit layout flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional planar layout constraint to a three-dimensional spatial arrangement by using capacitors with different grounding levels and connections. The first capacitor has one end grounded, the second capacitor has both ends grounded, and the third capacitor connects intermediate nodes, creating vertical and lateral spatial utilization that frees up layout space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If multiple capacitors with different grounding configurations are used, then spatial flexibility for circuit layout is improved, but device complexity increases

Engineering Contradiction:
Improvespace for circuit layoutVSAvoidqubit structure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

Multiple capacitors (first, second, and third capacitors) are merged into a single integrated qubit structure with the SQUID. The capacitors are interconnected such that they function as a unified quantum element rather than separate components, maintaining manageable device complexity while achieving spatial flexibility.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The multi-capacitor structure serves multiple functions simultaneously: it provides the necessary quantum energy levels through capacitive coupling, enables flexible circuit layout through different grounding configurations, and maintains compatibility with micro-nano machining fabrication processes. This multi-functionality justifies the increased structural complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design facilitates the layout of read resonant cavities and control signal lines, enhances qubit connectivity, and allows for the expansion of qubit numbers on a substrate by overcoming spatial constraints, thereby improving the integration and scalability of quantum circuits.

Implementation Method 1

a first device, including a first squid and a third capacitor that are connected in parallel

Methodology Applied
Scientific EffectSuperconducting quantum interference: Superconductivity

Implementation Method 2

a first device, including a first squid and a third capacitor that are connected in parallel

Methodology Applied
Scientific EffectJosephson effect: Josephson Effect

Data Source

PatentEP4328809B1Quantum circuit, quantum chip, and quantum computer
Publication Date: 2025.10.29 ORIGIN QUANTUM COMPUTING TECH (HEFEI) CO LTD
  • EP4328809B1 patent drawingFigure 1A~1B
  • EP4328809B1 patent drawingFigure 2~3
  • EP4328809B1 patent drawingFigure 4~5

AI summary

A quantum circuit, a quantum chip, and a quantum computer. The quantum circuit includes qubits, adjacent qubits being coupled, and each of the qubits including: a first capacitor, a first end of the first capacitor being grounded; a second capacitor, a first end of the second capacitor and the first end of the first capacitor being commonly grounded; and a first device, including a first squid and a third capacitor that are connected in parallel, wherein parallel-connected first ends of the first squid and the third capacitor are connected to a second end of the first capacitor, and parallel-connected second ends of the first squid and the third capacitor are connected to a second end of the second capacitor. According to the present disclosure, parameters of at least one of a plurality of capacitors in a qubit circuit can be adjusted, so that the design of the capacitor is more flexible and less spatially limited, which facilitates design and layout of other circuit structures.