Hybrid Quantum-Classical Variational Inference for Control Systems

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Solution Overview

Problem

Current methods for exact inference in complex systems, such as probabilistic graphical models, are computationally intractable, making approximate solutions desirable but challenging, especially in real-time control applications where accuracy and uncertainty quantification are crucial.

Innovation Solution

A hybrid computer system combining classical and quantum computers, utilizing a variational inference arrangement with a Born machine implemented on the quantum computer, which processes input data to generate output for controlling or monitoring physical systems, employing Bayesian network models and objective functions like Kullback-Leibler divergence and kernelized Stein discrepancy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If exact inference methods are used in probabilistic graphical models, then inference accuracy is improved, but computational complexity becomes intractable

Engineering Contradiction:
Improveinference accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a Born machine as an intermediary quantum system that mediates between the classical probabilistic graphical model and the inference task. The Born machine uses quantum states to represent probability distributions and quantum measurements to perform sampling, thereby avoiding the computational intractability of exact inference while maintaining inference accuracy through quantum mechanical principles.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the classical computational mechanism with a quantum mechanical system. Instead of using classical algorithms to compute probability distributions and perform sampling, the system uses quantum states, unitary transformations, and quantum measurements to achieve the same inferential goals with exponentially reduced computational complexity for certain problem classes.

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

2Measurement precision

If quantum computers are used to implement Born machine arrangements, then inference accuracy and control precision are enhanced, but device complexity increases

Engineering Contradiction:
Improveinference accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the overall system into distinct functional components: a classical computer for preparing quantum circuits and processing results, and a quantum computer for executing the Born machine inference tasks. This segmentation allows each component to be optimized independently and enables the system to leverage the strengths of both classical and quantum computing without requiring a fully quantum system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The Born machine arrangement is designed as a universal framework that can be applied to various probabilistic graphical models and inference tasks. The quantum circuit preparation and execution protocols are general-purpose, allowing the same quantum hardware to perform different inference tasks by simply changing the input quantum circuit parameters, thereby reducing the need for task-specific hardware complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If variational inference arrangements with Born machines are used, then control precision and energy efficiency are improved, but implementation complexity increases

Engineering Contradiction:
Improvecontrol precisionVSAvoidimplementation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-compiling and optimizing quantum circuits before execution on the quantum hardware. The classical computer prepares the quantum circuit parameters and structures in advance based on the specific inference task, allowing the quantum computer to focus solely on executing the prepared circuits. This preliminary preparation reduces the complexity of real-time quantum control and enables more precise control during actual execution.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20220292377A1Computer system and method for utilizing variational inference
Publication Date: 2022.09.15 QUANTINUUM LTD
  • US20220292377A1 patent drawing
  • US20220292377A1 patent drawing
  • US20220292377A1 patent drawing

AI summary

A computing system that includes a quantum computer, wherein the computing system is configured to use variational inference methods based on input data derived from an apparatus to be controlled, and to output data for controlling the operation of the apparatus. Methods for using the computing system for controlling operation of the apparatus. The computing system uses variational inference methods configured to drawing conclusion about unobserved variable given observations of related variables, to control the apparatus. The computing system may use Bayesian networks, quantum Born machines, adversarial objectives, or kernelized Stein discrepancy, to perform variational inference.