Grid-Based Photonic Circuit for Parallel GHZ State Generation

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Solution Overview

Problem

Existing photonic circuits face challenges in efficiently generating multi-partite entangled quantum states, particularly GHZ states, due to limited success probability and decoherence during the generation process of Einstein-Podolsky-Rosen (EPR) pairs, which hinders optimal quantum error correction.

Innovation Solution

A photonic circuit with a grid of unit cells and optical interconnects, equipped with optical switches for dynamic reconfiguration, allows flexible topology and direct generation of multi-partite states by selectively coupling qubits with optical interfaces, enabling on-the-fly selection of GHZ states and supporting error correction codes like the surface code.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If EPR pairs are generated sequentially to compose GHZ states, then multi-partite entangled states can be created, but the success probability is limited and decoherence occurs during the generation process

Engineering Contradiction:
Improvesuccess probability of GHZ state generationVSAvoidtime for sequential EPR pair generation
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The photonic circuit is divided into multiple unit cells, each capable of independently generating and manipulating quantum states. This segmentation allows parallel processing of quantum operations across different unit cells, eliminating the sequential bottleneck in EPR pair generation and thereby improving both success probability and reducing time loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from sequential temporal generation of EPR pairs to a spatially parallel architecture where multiple unit cells operate simultaneously. By adding the spatial dimension to the generation process, multiple entangled pairs can be created in parallel rather than sequentially, directly addressing the time loss and success probability issues.

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

2Adaptability or versatility

If a fixed photonic coupling topology is used, then the circuit structure is simple, but the flexibility to select properly conditioned qubits for quantum computations is limited

Engineering Contradiction:
Improveflexibility to select qubits for quantum proceduresVSAvoidcircuit topology structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The photonic circuit employs dynamic reconfigurable coupling between unit cells, allowing the topology to be changed on-demand. Optical switches and controllable coupling mechanisms enable the system to adapt its connectivity pattern based on the specific quantum computation requirements, providing flexibility to select properly conditioned qubits while managing complexity through controlled reconfigurability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Each unit cell is designed with universal functionality to perform multiple quantum operations and interact with neighboring cells through reconfigurable coupling. This multi-functionality allows the same hardware structure to serve different quantum computational procedures, enhancing adaptability without proportionally increasing overall device complexity.

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

3Reliability

If multiple qubits are physically connected to form logical qubits, then quantum error correction can be applied, but the complexity of connecting and interacting between qubits increases

Engineering Contradiction:
Improvequantum error correction capabilityVSAvoidqubit connection and interaction structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system segments qubits into modular unit cells, each self-contained with necessary quantum components. This segmentation simplifies the connection structure by creating standardized interfaces between cells, making it easier to scale up the number of qubits while maintaining manageable complexity through modular architecture that supports error correction protocols.

Inventive Principle:
Principle #1Segmentation

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

Enhances the success probability of generating multi-partite entangled quantum states, particularly GHZ states, by providing a flexible and efficient architecture for quantum computations, facilitating error correction and improving the performance of quantum processors.

Implementation Method 1

generating multi-partite entangled quantum states between qubits

Methodology Applied
Scientific EffectQuantum entanglement:

Implementation Method 2

one or more optical switches that allow a dynamic reconfiguration of the optical interconnects

Methodology Applied
Scientific EffectOptical switching:

Data Source

PatentEP4636658A1A photonic circuit for generating multi-partite quantum states between qubits
Publication Date: 2025.10.22 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP4636658A1 patent drawingFigure 1~1C
  • EP4636658A1 patent drawingFigure 2A~2B
  • EP4636658A1 patent drawingFigure 3

AI summary

A photonic circuit for generating multi-partite entangled quantum states between qubits, comprising: A first grid 200 of optical interconnects suitable for providing photons of suitable laser sources L1-L4 to one or more single photon sources 20, preferably within the unit cells 100 for generating a single photon e; said one or more single photon sources 20 having output terminals e photonically coupled to a second grid 300 of optical interconnects. The photonic circuit may comprise at least one single photon detector 30 having input terminals photonically coupled to a second grid 300. A further grid may be provided for quantum mechanically conditioning of the qubits in said unit cells into a specific quantum state. The optical switches of the grid 300 may selectively direct said single photon e over said grid 300 between unit cells 100 to a selected qubit 10 in a selected unit cell 100.