Quantum Boltzmann Machine Training via POVM and Golden-Thompson Methods

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Solution Overview

Problem

Classical Boltzmann machines are incapable of learning quantum terms from classical data and are not truly quantum, as their training procedures can be simulatable using quantum Monte-Carlo methods, limiting their ability to model complex quantum states effectively.

Innovation Solution

The development of quantum Boltzmann machines that utilize POVM-based and state-based training methods, including Golden-Thompson and relative entropy training approaches, to learn non-stoquastic Hamiltonians, enabling the training of quantum models that can perform tomographic reconstructions and generate quantum data models.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If classical Boltzmann machines are used for training, then the training procedure can be simulated using quantum Monte-Carlo methods, but the ability to model complex quantum states is limited

Engineering Contradiction:
ImprovetrainabilityVSAvoidability to model quantum states
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent replaces classical Boltzmann machine training mechanisms with quantum mechanical systems. Specifically, it uses quantum Boltzmann machines that leverage quantum effects such as superposition and entanglement to train on quantum data, substituting the classical probabilistic framework with a quantum framework that can naturally represent quantum states

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

Solution Approach 2:

The patent changes the fundamental parameters of the Boltzmann machine by introducing quantum terms in the Hamiltonian. The energy function is modified to include quantum operators and expectations, transforming the classical parameters (weights and biases) into quantum operators that act on quantum states, enabling the model to capture quantum correlations

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If quantum Boltzmann machines are used to learn non-stoquastic Hamiltonians, then the ability to model complex quantum states is improved, but the training complexity increases

Engineering Contradiction:
Improveability to model quantum statesVSAvoidtraining complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the training process into distinct quantum and classical components. The quantum computer prepares states and measures expectations, while a classical optimizer adjusts parameters. This segmentation allows each component to handle tasks it is best suited for, reducing overall training complexity despite the quantum nature of the model

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary classical computer that mediates between the quantum hardware and the optimization algorithm. The classical computer processes measurement results from the quantum device and generates parameter updates, acting as a bridge that simplifies the interaction between quantum and classical systems during training

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11157828B2Tomography and generative data modeling via quantum boltzmann training
Publication Date: 2021.10.26 MICROSOFT TECHNOLOGY LICENSING LLC
  • US11157828B2 patent drawing
  • US11157828B2 patent drawing
  • US11157828B2 patent drawing

AI summary

Quantum neural nets, which utilize quantum effects to model complex data sets, represent a major focus of quantum machine learning and quantum computing in general. In this application, example methods of training a quantum Boltzmann machine are described. Also, examples for using quantum Boltzmann machines to enable a form of quantum state tomography that provides both a description and a generative model for the input quantum state are described. Classical Boltzmann machines are incapable of this. Finally, small non-stoquastic quantum Boltzmann machines are compared to traditional Boltzmann machines for generative tasks, and evidence presented that quantum models outperform their classical counterparts for classical data sets.