Analog Quantum Gate Preparation for Single-Qubit Addressability

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Solution Overview

Problem

Existing analog quantum computers face challenges in implementing single-qubit addressability and two-qubit gates due to always-on interactions, limiting their connectivity and operational flexibility.

Innovation Solution

A method involving a combination of global and local rotations, optimized through variational techniques, to approximate single-qubit gates and enable effective pulse sequences for addressing qubits, allowing for the implementation of SWAP networks and improved state preparation in analog quantum systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If global rotations are applied to all particles in an analog quantum computer, then the system can implement quantum operations, but single-qubit addressability is lost and connectivity is limited

Engineering Contradiction:
Improvesingle-qubit addressabilityVSAvoidconnectivity control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the quantum operation into three distinct rotation components: a first global rotation applied to all particles, a second local rotation applied to a specific target particle, and a third global rotation applied to all particles. This segmentation allows the system to achieve single-qubit addressability through the combination of global and local operations, resolving the contradiction between global applicability and individual addressability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges three rotation operations (two global rotations and one local rotation) into a composite sequence that achieves effective single-qubit addressing. By combining these rotations in a specific order and with optimized parameters through variational methods, the system achieves both global coherence and local addressability simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If variational optimization is used to determine pulse sequences, then gate approximation accuracy improves, but computational time and complexity increase

Engineering Contradiction:
Improvegate approximation accuracyVSAvoidoptimization time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent employs variational optimization to pre-determine the optimal parameters for the pulse sequence before actual quantum operations are executed. By performing the optimization in advance on a classical computer and then applying the predetermined pulse sequence on the quantum hardware, the system achieves high gate accuracy without incurring optimization time during quantum computation, effectively separating the optimization phase from the execution phase.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4579539A1Method for preparing gates in an analog quantum computer
Publication Date: 2025.07.02 PASQAL SAS
  • EP4579539A1 patent drawingFigure 1
  • EP4579539A1 patent drawingFigure 2a
  • EP4579539A1 patent drawingFigure 2b

AI summary

A method of determining a pulse sequence to apply an approximation of a local rotation in a first basis of a three-basis coordinate system to a particle of a plurality of particles in a quantum computer, wherein a set of particles having one or more particles of the plurality of particles is associated with a corresponding qubit of a plurality of qubits, the method comprising: identifying a first global rotation in a second basis of the three-basis coordinate system to apply to the plurality of particles, the second basis being different to the first basis; a local rotation in a third basis of the three-basis coordinate system to apply to the particle, the third basis being different from each of the first and second bases; a second global rotation in the second basis to apply to the plurality of particles; whereby the ordered combination of the first global rotation, the local rotation and the second global rotation approximate the local rotation in the first basis.