Quantum Distance Determination via Interference

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Solution Overview

Problem

Current noisy intermediate-scale quantum (NISQ) computing devices face limitations in coherence time and interconnection design, leading to inefficiencies in quantum circuit depth and accuracy for distance-based classification tasks, particularly in machine learning applications like k-means clustering.

Innovation Solution

A method and apparatus for determining distances between quantum states using quantum interference, involving manipulation of qubits based on test and training vectors, with measurements to calculate distances and classify vectors, optimized for NISQ devices by employing shorter quantum circuits and entanglement techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If quantum interference is used to determine distance between quantum states, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvedistance calculation accuracyVSAvoidquantum circuit depth
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The quantum circuit is divided into modular components: state preparation modules that encode training and test vectors, an interference module that applies the core quantum interference operation, and measurement modules that extract distance information. This segmentation allows each component to be optimized independently and reduces overall circuit depth while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies quantum interference selectively only to the relevant portions of the quantum states that contribute to distance calculation, rather than processing entire state vectors. This partial action approach reduces the number of required quantum gates and circuit depth while preserving the essential interference effects needed for accurate distance determination.

Inventive Principle:
Principle #16Partial or excessive action

2Productivity

If quantum interference patterns are leveraged for distance calculation, then productivity is improved, but reliability deteriorates due to NISQ device limitations

Engineering Contradiction:
Improvespeed of distance calculationVSAvoidcomputation accuracy on NISQ devices
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent prepares quantum states in advance with proper encoding of training vectors and establishes the initial superposition states before the interference operation. This preliminary state preparation ensures that when the interference occurs, the quantum states are already optimized for the distance calculation task, reducing the need for additional corrective operations that would increase circuit depth and error rates on NISQ devices.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent acknowledges and works within the noise constraints of NISQ devices by designing interference circuits that are robust to certain types of noise. The quantum interference pattern itself provides inherent error mitigation through the probabilistic nature of quantum measurement, where multiple measurements can statistically overcome individual shot noise events, converting the harmful noise into a manageable statistical variation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

This approach enables efficient distance calculation and classification on NISQ devices, improving the accuracy and speed of quantum machine learning tasks, such as k-means clustering, by leveraging quantum interference patterns and reducing the complexity of quantum circuit depth.

Implementation Method 1

performing quantum interference between the test vector and the training vector

Methodology Applied
Scientific EffectQuantum interference: Interference

Data Source

PatentUS11727298B2Determining a distance
Publication Date: 2023.08.15 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US11727298B2 patent drawing
  • US11727298B2 patent drawing
  • US11727298B2 patent drawing

AI summary

Methods and apparatus are disclosed, including an example of a method of determining a distance between a first point and a second point. The method includes manipulating quantum states of at least first and second qubits of a quantum computing device based on a test vector representing the first point and a training vector representing the second point, performing quantum interference between the test vector and the training vector, performing a measurement on one or more of the qubits to determine the distance, and determining the distance from the measurement.