Quantum Node Synchronization Using Discretized Transmission Times

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Solution Overview

Problem

Existing methods for synchronizing events in quantum networks face challenges with scalability, efficiency, and precision due to unpredictable preparatory stages and transmission delays, especially at geographically distant nodes, leading to inefficiencies and high failure rates.

Innovation Solution

A method involving discretizing transmission times into a synchronized set of allowed times based on transmission delay distributions, using high-precision clocks, to ensure precise and efficient synchronization across multiple nodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If standard computing devices are used to determine start time, then device complexity is reduced, but timing precision deteriorates and cannot meet the 1 ns synchronization requirement

Engineering Contradiction:
Improvetiming precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a dedicated timing determination device as an intermediary component between the standard microcontroller and the operational stage. This specialized device receives signals from both nodes, determines the start time based on received signals and transmission delay information, and provides precise timing control. This intermediary handles the high-precision timing requirements while allowing standard microcontrollers to manage overall system control, thus resolving the contradiction between timing precision and device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the period between entanglement attempts is increased to allow for preparation completion, then reliability improves, but productivity deteriorates due to reduced attempt frequency

Engineering Contradiction:
Improveentanglement success rateVSAvoidentanglement attempt rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic adjustment of the period between entanglement attempts based on the actual preparation completion times of the nodes. The system monitors whether nodes have finished preparation and adapts the timing of subsequent attempts accordingly, rather than using a fixed periodic schedule. This dynamic approach allows the system to maximize attempt frequency while ensuring nodes are ready, thus resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms where nodes communicate their preparation status to the timing determination device. This feedback information is used to adjust the timing of entanglement attempts, allowing the system to optimize the balance between waiting for preparation completion (reliability) and maintaining high attempt frequency (productivity).

Inventive Principle:
Principle #23Feedback

3Reliability

If transmission delay uncertainty is accommodated with larger time intervals, then reliability of synchronization improves, but loss of time increases reducing network throughput

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidsynchronization time overhead
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary determination of transmission delay information between nodes before the actual entanglement attempts. This transmission delay information is stored and reused for timing calculations, eliminating the need to repeatedly measure and accommodate transmission delays. By preparing this information in advance, the system can use precise timing intervals without sacrificing synchronization reliability, thus resolving the contradiction between reliability and time loss.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4430770B1Sub-nanosecond synchronisation of nodes in a quantum network
Publication Date: 2025.12.31 TECH UNIV DELFT
  • EP4430770B1 patent drawingFigure 1
  • EP4430770B1 patent drawingFigure 2A~2B
  • EP4430770B1 patent drawingFigure 3A~3C

AI summary

Methods and systems are disclosed for synchronising events at a plurality of nodes in a quantum network. The method comprises determining transmission delay information comprising a maximum transmission delay a about a transmission delay distribution of signals transmitted between a first node comprising a first qubit and a second node comprising a second qubit. The method further comprises determining a synchronised set of allowed transmission times based on the transmission delay distribution, and based on a synchronized clock shared between the nodes. The method further comprises executing, by the first node, a first qubit operation based on a start time. The execution by the first node includes initializing the first qubit and transmitting a first initialisation signal to the second node based on a first allowed transmission time selected from the set of allowed transmission times; receiving a second initialisation signal from the second node indicative of initialisation of the second qubit and transmitted by the second node based on a second allowed transmission time selected from the set of allowed transmission times; determining the second allowed transmission time based on the second initialisation signal; and determining the start time for the first qubit operation based on the first and second allowed transmission times, the transmission delay information and the synchronised clock.