Quantum Processor 3D Control Architecture for Scalable Error Correction

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Solution Overview

Problem

Current quantum processor architectures are not scalable for implementing error-corrected quantum computing over millions of qubits due to the high cost of control lines and lack of efficient methods for error correction.

Innovation Solution

A quantum processor architecture using a two-dimensional matrix of donor atoms in silicon, where data and ancilla qubits are encoded in nuclear spins, allowing for simultaneous control using multiplexed control lines and avoiding electron wave-function engineering, enabling surface code error correction with reduced operational errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate control lines are used to address each individual qubit in a planar quantum computing architecture, then each qubit can be precisely controlled, but the space required for control lines scales linearly with the number of qubits, making the architecture non-scalable

Engineering Contradiction:
Improvequbit control precisionVSAvoidspace for control lines
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent transitions from a planar 2D arrangement to a 3D vertical stacking architecture. Control members are positioned above and below the qubit plane, allowing multiple control lines to intersect and address different qubits without requiring proportional horizontal space. This dimensional change enables O(sqrt(N)) scaling of control lines for N qubits.

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

Solution Approach 2:

Each control member is designed to control multiple qubits simultaneously rather than being dedicated to a single qubit. The control members can selectively address different qubits along their length, enabling one control line to serve multiple functions and reducing the total number of control lines required.

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

2Ease of operation

If a large number of control lines are used to address individual qubits, then precise quantum control is achieved, but the device complexity and fabrication difficulty increase significantly

Engineering Contradiction:
Improvequantum control precisionVSAvoidcontrol structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

By moving control members to vertical planes above and below the qubit layer, the patent reduces the horizontal complexity of routing control lines. The 3D arrangement allows control members to cross without interference, simplifying the overall device structure while maintaining individual qubit addressability.

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

Solution Approach 2:

The control structure is divided into separate control members positioned in different vertical planes. Each control member can be independently fabricated and controlled, modularizing the complex control system into manageable segments that can be addressed individually.

Inventive Principle:
Principle #1Segmentation

3Productivity

If conventional quantum processor architectures are used, then quantum computation can be performed, but they cannot efficiently implement error corrected quantum computation over millions of qubits due to linear scaling requirements

Engineering Contradiction:
Improvequantum computation capabilityVSAvoidscalability to millions of qubits
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The vertical stacking architecture enables the system to scale to millions of qubits by utilizing the third dimension. Instead of requiring a horizontally expanding plane that would require proportional control line growth, the system can vertically stack multiple qubit layers with shared control members, achieving polynomial rather than linear scaling.

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

Solution Approach 2:

The control members are designed with adjustable electrostatic potentials that allow dynamic selection of which qubits to address. This dynamic control capability enables the same physical control member to adaptively serve different qubits based on computational requirements, enhancing the system's versatility and scalability.

Inventive Principle:
Principle #15Dynamics

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 architecture achieves high-level error-corrected logical operations with operational errors below the surface code threshold, allowing for scalable and efficient quantum computing by simplifying control and reducing the complexity of quantum operations.

Implementation Method 1

switching, for a predetermined number of times, one or more electrostatic signals applied to respective control members from a first configuration to a second configuration, wherein the first configuration of signals is such to prevent quantum tunnelling of the electron to or from the donor atom and the second configuration of signals is such to permit quantum tunnelling of the electron to or from the donor atom

Methodology Applied
Scientific EffectQuantum tunnelling:

Implementation Method 2

applying a magnetic field to the donor atom with a loaded electron, the magnetic field being in resonance with the nuclear spin of the donor atom; allowing coherent rotation of the nuclear spin by an angle θ

Methodology Applied
Scientific EffectNuclear spin precession:

Implementation Method 3

the strength of the exchange-interaction

Methodology Applied
Scientific EffectExchange interaction:

Implementation Method 4

A plurality of donor atoms may be arranged to facilitate electromagnetic coupling between one or more of the qubit elements

Methodology Applied
Scientific EffectElectromagnetic coupling:

Data Source

PatentEP3016034B1A quantum processor
Publication Date: 2020.03.18 NEWSOUTH INNOVATIONS PTY LTD
  • EP3016034B1 patent drawingFigure 1
  • EP3016034B1 patent drawingFigure 2
  • EP3016034B1 patent drawingFigure 3

AI summary

The present disclosure provides a quantum processor realised in a semiconductor material and method to operate the quantum processor to implement error corrected quantum computation. The quantum processor comprises a plurality of qubit elements disposed in a two-dimensional matrix arrangement. The qubits are implemented using the nuclear or electron spin of phosphorus donor atoms. Further, the processor comprises a control structure with a plurality of control members, each arranged to control a plurality of qubits disposed along a line or a column of the matrix. The control structure is controllable to perform topological quantum error corrected computation.