Hamilton-Cyclic Sequence for Quantum Signal Alignment

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Solution Overview

Problem

Current quantum communication systems require lengthy synchronization and alignment procedures due to the need for iterative scans and non-unique frame patterns, leading to inefficient alignment and potential errors in quantum key distribution.

Innovation Solution

Employing a Hamilton-Cyclic sequence with unique sub-sequences that allow for single-measurement alignment, eliminating the need for iterative scans and reducing alignment time by at least 50%.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional iterative scan alignment procedures are used, then alignment reliability is improved through multiple measurements, but alignment time increases significantly

Engineering Contradiction:
Improvealignment reliabilityVSAvoidalignment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-designing a Hamilton-Cyclic sequence with unique sub-sequences before the alignment process. This pre-structured sequence enables the receiver to determine alignment in a single measurement without iterative scanning, thus reducing alignment time while maintaining reliability through the inherent uniqueness of the sequence patterns.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the fundamental parameter of the alignment sequence from conventional repetitive patterns to Hamilton-Cyclic sequences with unique sub-sequences. This parameter change allows the system to achieve alignment through single-measurement pattern recognition rather than iterative scanning, resolving the contradiction between speed and reliability.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If conventional non-unique frame patterns are used, then device complexity is reduced with simpler sequences, but alignment precision deteriorates due to ambiguity in pattern recognition

Engineering Contradiction:
Improvesequence complexityVSAvoidalignment precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the Hamilton-Cyclic sequence into unique sub-sequences of specific lengths. Each sub-sequence acts as an independent identifier that can be recognized unambiguously, improving alignment precision while keeping the overall structure manageable through systematic segmentation of the sequence into recognizable units.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces asymmetry by designing Hamilton-Cyclic sequences where each sub-sequence has a unique pattern that differs from all others. This asymmetric design eliminates the ambiguity present in symmetric or repetitive conventional sequences, enabling precise alignment determination through single-measurement pattern recognition.

Inventive Principle:
Principle #4Asymmetry

3Measurement precision

If multiple iterative scans are performed for alignment, then measurement precision is improved through repeated measurements, but productivity decreases due to slower alignment speed

Engineering Contradiction:
Improvealignment measurement precisionVSAvoidalignment speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements feedback through the unique structure of Hamilton-Cyclic sequences, where the receiver can immediately determine alignment status from a single measurement by recognizing the unique sub-sequence pattern. This eliminates the need for repeated measurements while maintaining precision, thereby improving productivity through faster alignment speed.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies skipping by eliminating the iterative scanning process entirely. The unique Hamilton-Cyclic sequence allows the system to rush through the alignment process in a single measurement, achieving both high precision and high speed by skipping the time-consuming repeated measurement steps of conventional methods.

Inventive Principle:
Principle #21Skipping (Rushing through)

Data Source

PatentEP3787220B1Quantum communication synchronization and alignment procedure
Publication Date: 2023.04.12 ID QUANTIQUE SA
  • EP3787220B1 patent drawingFigure 1
  • EP3787220B1 patent drawingFigure 2
  • EP3787220B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a synchronization method, in particular an alignment method to be implemented in a quantum communication system, being adapted to align the indices of the exchanged signals and comprising the steps of producing a sequence of n quantum signals wherein the pattern of each arbitrary sub-sequence made of k consecutive quantum channel signals within the whole sequence of n quantum channel signals is unique in the whole sequence such that said whole sequence presents an Hamilton-cyclic pattern, repeatedly sending said sequence from the transmitter over the quantum channel to the receiver, detecting a arbitrary selected sub-sequence pattern of said sequence, calculating correlation factors between the pattern of detected sub-sequence and all the possible patterns in the Hamiltonian-Cycle sequence, and determining the current sub-sequence and a required sub-sequence offset based on the pattern with the highest correlation factor, and aligning the phases of the emitter and the receiver based on the determined offset.