Quantum Emitter Entanglement Distribution for Fixed-Depth GHZ Projection

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Solution Overview

Problem

Generating multipartite entangled states, such as Greenberger-Horne-Zeilinger (GHZ) states, over optical fibers is challenging due to loss and limitations in linear optics for GHZ measurements.

Innovation Solution

Utilizing optical channels coupled with electron-nuclear memories, specifically silicon vacancy quantum memories, and near-deterministic Bell measurements between electronic spins to achieve deterministic GHZ state projection, involving electron-electron entanglement and nuclear spin swapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multipartite entangled states are generated over optical fibers, then quantum communication is enabled, but loss and linear optics limitations reduce reliability

Engineering Contradiction:

Improveentanglement distribution reliabilityVSAvoidphoton loss in optical fibers

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent uses quantum memories as intermediary devices to store quantum states locally at multiple nodes, eliminating the need for direct long-distance photon transmission. The quantum memories act as mediators that hold entangled states until measurement, overcoming photon loss in optical fibers by converting flying qubits (photons) into stationary qubits (trapped ion states).

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/optical system of direct photon transmission through fibers with a quantum logic system using trapped ions and laser-induced entanglement. Instead of relying on photon propagation through lossy media, the system uses controlled quantum operations on trapped ions to generate and distribute entangled states deterministically.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If linear optics are used for GHZ measurements, then measurement capability is provided, but the ability to perform GHZ measurements is limited

Engineering Contradiction:

ImproveGHZ measurement capabilityVSAvoidmeasurement system limitations

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces linear optical measurement systems with direct quantum logic operations on trapped ions. Instead of using beam splitters and photodetectors that have inherent limitations for GHZ measurements, the system uses laser-controlled quantum gates and state detection on trapped ions, enabling deterministic GHZ measurements without the constraints of linear optics.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If entanglement is distributed over multiple nodes, then quantum communication network is formed, but decoherence issues arise

Engineering Contradiction:

Improvemulti-node quantum network capabilityVSAvoidquantum state coherence

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent uses quantum memories based on trapped ions as intermediary storage devices that maintain quantum coherence locally at each node. These quantum memories serve as stable repositories for entangled states, isolating them from environmental decoherence while enabling network-wide quantum communication through controlled state transfer and measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables the reliable and efficient distribution of GHZ states among multiple nodes by ensuring long-term entanglement maintenance through nuclear spins, overcoming decoherence issues and enhancing communication systems.

Implementation Method 1

an optical channel coupled with electron-nuclear memories

Methodology Applied

Scientific EffectPhoton propagation: Light

Implementation Method 2

electron-nuclear memories, such as silicon vacancy quantum memories

Methodology Applied

Scientific EffectSpin states:

Implementation Method 3

near-deterministic Bell measurements between electronic spins

Methodology Applied

Scientific EffectQuantum entanglement:

Implementation Method 4

nuclear spin swapping

Methodology Applied

Scientific EffectSpin swapping:

Data Source

PatentUS20250309997A1Distributing an entangled state among multiple nodes using quantum emitters

Publication Date: 2025.10.02 CISCO TECHNOLOGY INC

AI summary

An embodiment provides for distribution of an entangled state (e.g., GHZ state, etc.) through use of an optical channel coupled with electron-nuclear memories, such as silicon vacancy quantum memories, and near-deterministic Bell measurements between electronic spins. The embodiment provides electron-nuclear spin swapping and deterministically generates electron-electron entanglement. Nuclear spins can be used for memories, and repeated Bell measurements can be used to generate entanglements between electrons. Thus, the embodiment obtains a deterministic GHZ projection and prepares the GHZ state in fixed circuit depth.