Quantum Walk Circuit for Metropolis-Hastings Optimization

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Solution Overview

Problem

Existing quantum walk implementations for Markov chain Monte Carlo simulations on quantum computers require costly arithmetic operations and inefficient handling of rejected updates, hindering efficient acceleration of random walks.

Innovation Solution

Reformulating the quantum walk to circumvent the need for costly arithmetic operations and implementing a quantum move register that can be reset at every step, along with a heuristic quantum algorithm using the quantum walk for discrete optimization problems, and employing a quantum walk procedure with intermediate measurements and rewinding procedures for incorrect outcomes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If quantum computers are used to solve combinatorial optimization problems, then computational speed can be exponentially accelerated, but the technology is not yet ready for practical use and requires complex quantum hardware

Engineering Contradiction:
Improvecomputational speedVSAvoidquantum hardware complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces physical quantum mechanical systems with a mathematical simulation model. Instead of requiring actual quantum hardware with qubits and quantum gates, the invention uses classical computers to simulate quantum walk processes through probability distribution calculations, thereby achieving quantum computational benefits without quantum hardware complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a probability distribution function as an intermediary between the classical computer and the optimization problem. This mathematical intermediary enables the simulation of quantum effects (superposition and interference) without direct quantum hardware, allowing classical systems to achieve quantum-like computational performance

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If existing quantum algorithms like Grover's algorithm are used, then quadratic speedup can be achieved, but they require complex quantum circuits and are difficult to implement

Engineering Contradiction:
Improvecomputational speedupVSAvoidquantum circuit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent substitutes complex quantum circuit implementations with a simplified mathematical framework based on probability distributions. The quantum walk process is simulated through classical probability calculations rather than physical quantum gate operations, maintaining speedup benefits while eliminating circuit complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameters of quantum computation from discrete quantum states and gate operations to continuous probability distribution functions. This parameter transformation allows the system to achieve quantum-like computational efficiency using classical mathematical operations

Inventive Principle:
Principle #35Parameter changes

3Reliability

If quantum random access memory is used to store quantum states, then quantum information can be preserved, but the system becomes even more complex and harder to build

Engineering Contradiction:
Improvequantum state preservationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces quantum memory requirements with classical data structures that store probability distribution values. Instead of needing quantum random access memory to preserve quantum states, the system uses classical arrays or matrices to store probability amplitudes, eliminating the need for quantum memory while maintaining computational integrity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3837645B1A quantum-walk-based algorithm for classical optimization problems
Publication Date: 2026.05.06 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3837645B1 patent drawingFigure 1
  • EP3837645B1 patent drawingFigure 2
  • EP3837645B1 patent drawingFigure 3

AI summary

Example circuit implementations of Szegedy's quantization of the Metropolis-Hastings walk are presented. In certain disclosed embodiments, a quantum walk procedure of a Markov chain Monte Carlo simulation is implemented in which a quantum move register is reset at every step in the quantum walk. In further embodiments, a quantum walk procedure of a Markov chain Monte Carlo simulation is implemented in which an underlying classical walk is obtained using a Metropolis-Hastings rotation or a Glauber dynamics rotation. In some embodiments, a quantum walk procedure is performed in the quantum computing device to implement a Markov Chain Monte Carlo method; during the quantum walk procedure, an intermediate measurement is obtained; and a rewinding procedure of one or more but not all steps of the quantum walk procedure is performed if the intermediate measurement produces an incorrect outcome.