Quantum State Compression via Hybrid Ansatz Generation

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Solution Overview

Problem

Variational quantum algorithms face challenges in optimizing quantum circuits due to high-dimensional black-box optimization problems, particularly in noisy intermediate-scale quantum (NISQ) devices, where qubits are expensive and sensitive to error, and the optimization landscape has vanishingly small gradients, making it difficult to compress quantum states effectively.

Innovation Solution

A hybrid quantum-classical computer system is employed to generate matrix product state (MPS) approximations and construct a variational quantum circuit using classical subroutines, which are then optimized to compress quantum states into fewer qubits, utilizing techniques like QR decomposition and entanglement capturing to refine the circuit ansatz.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If variational quantum algorithms are used for quantum state compression, then both classical and quantum computers can be utilized, but the optimization landscape has vanishingly small gradients making optimization difficult

Engineering Contradiction:
Improvehybrid quantum-classical capabilityVSAvoidoptimization landscape gradient
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by using a classical computer to generate an educated initial guess of a good quantum circuit (ansatz) before quantum optimization begins. This preliminary classical preparation step provides a starting point that is already close to optimal, avoiding the vanishing gradient problem that plagues random initialization in high-dimensional quantum parameter spaces.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If quantum circuit parameters are optimized for larger problem sizes, then more accurate compression is achieved, but the number of parameters grows creating high-dimensional black-box optimization problems

Engineering Contradiction:
Improvecompression accuracyVSAvoidnumber of optimization parameters
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the optimization task into two parts: a classical computer handles the generation of the initial ansatz structure, while the quantum computer handles the final parameter optimization. This segmentation allows the system to tackle larger problem sizes without proportionally increasing the difficulty of optimization, as the classical pre-processing reduces the effective search space.

Inventive Principle:
Principle #1Segmentation

3Productivity

If quantum state compression is performed on NISQ devices, then quantum computing capabilities are utilized, but qubits are expensive and sensitive to error

Engineering Contradiction:
Improvequantum computing utilizationVSAvoidqubit error sensitivity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing classical pre-computation to generate an optimized ansatz before quantum execution. This reduces the number of quantum circuit evaluations needed during optimization, thereby minimizing exposure to noise and errors on NISQ devices while still achieving effective compression.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies self-service by having the classical computer perform the heavy lifting of ansatz construction and optimization, allowing the quantum computer to focus only on the final, refined optimization steps where it provides unique value. This division allows the quantum system to serve itself efficiently without being overwhelmed by tasks better suited for classical computation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS11663513B2Quantum computer with exact compression of quantum states
Publication Date: 2023.05.30 ZAPATA COMPUTING INC
  • US11663513B2 patent drawing
  • US11663513B2 patent drawing
  • US11663513B2 patent drawing

AI summary

A quantum computer includes an efficient and exact quantum circuit for performing quantum state compression.