Short Depth Quantum Circuits for High-Dimensional Classification

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Solution Overview

Problem

Existing machine-learning classifiers face inefficiencies in processing time and accuracy due to their reliance on classical computing methods, which struggle with the complexity of classification tasks involving large feature spaces and high-dimensional data.

Innovation Solution

The implementation of short depth quantum circuits as quantum classifiers, which utilize quantum hardware to calibrate and optimize parameters through a cost function, enabling faster and more accurate classification by leveraging quantum parallelism and error correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If classical computing methods are used for machine-learning classification, then the system is easier to implement, but processing time increases and accuracy decreases for high-dimensional data

Engineering Contradiction:
Improveprocessing speedVSAvoidcomputational complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces classical computing mechanisms with quantum computing mechanisms. Specifically, it uses quantum circuits with qubits to perform classification tasks that are computationally intensive for classical systems. The quantum classifier leverages quantum parallelism and interference to process high-dimensional data more efficiently, substituting the mechanical/electrical operations of classical computers with quantum mechanical operations.

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

Solution Approach 2:

The patent exploits the unique properties of quantum state space to handle high-dimensional classification problems. By mapping classical data into quantum states and utilizing the exponential dimensionality of quantum Hilbert space, the system can process complex feature spaces that would require prohibitively large classical computational resources. This dimensional advantage allows quantum classifiers to achieve better performance on high-dimensional datasets.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If quantum hardware is used to implement classifiers, then processing accuracy and speed improve, but device complexity and calibration requirements increase

Engineering Contradiction:
Improveclassification accuracyVSAvoidquantum hardware complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs parameterized quantum circuits where the classification task is solved by optimizing specific parameters (rotation angles, coupling strengths) of quantum gates. This approach transforms the complex quantum hardware control problem into a parameter optimization problem that can be tackled using classical optimization algorithms. By changing and optimizing these parameters based on training data, the system achieves high classification accuracy while managing hardware complexity through software-controlled parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback loop where the quantum classifier's performance is continuously monitored and used to adjust the circuit parameters. A cost function evaluates the classification accuracy, and this feedback drives the optimization process to refine the quantum circuit parameters. This feedback mechanism allows the system to adapt to hardware imperfections and achieve high precision despite the inherent complexity and noise in quantum hardware.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If deeper quantum circuits are used to increase accuracy, then classification performance improves, but noise and decoherence effects increase

Engineering Contradiction:
Improveclassification accuracyVSAvoidnoise resistance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent adopts a pragmatic approach by using sufficiently deep quantum circuits to achieve the required classification accuracy without pursuing maximum circuit depth. The variational quantum classifier uses just enough quantum resources to solve the classification task effectively, avoiding the excessive circuit depth that would amplify noise and decoherence effects. This partial action principle balances accuracy requirements with reliability constraints by not over-engineering the circuit depth beyond what is necessary.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent employs dynamically adjustable quantum circuits where the circuit depth and structure can be adapted based on the specific classification task and available quantum resources. Rather than using fixed deep circuits, the system dynamically optimizes the circuit architecture and parameter values for each task, allowing it to achieve high accuracy while maintaining reliability by adjusting circuit complexity to match the problem requirements and hardware capabilities.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10977546B2Short depth circuits as quantum classifiers
Publication Date: 2021.04.13 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US10977546B2 patent drawing
  • US10977546B2 patent drawing
  • US10977546B2 patent drawing

AI summary

Techniques using short depth circuits as quantum classifiers are described. In one embodiment, a system is provided that comprises: quantum hardware, a memory that stores computer-executable components and a processor that executes computer-executable components stored in the memory. In one implementation, the computer-executable components comprise a calibration component that calibrates quantum hardware to generate a short depth quantum circuit. The computer-executable components further comprise a cost function component that determines a cost function for the short depth quantum circuit based on an initial value for a parameter of a machine-learning classifier. The computer-executable components further comprise a training component that modifies the initial value for the parameter during training to a second value for the parameter based on the cost function for the short depth quantum circuit.