Qubit Crosstalk Analysis via Spectral Quantum Process Tomography

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Solution Overview

Problem

Conventional qubit crosstalk analysis methods using Clifford gates and randomized benchmark tests fail to provide detailed insights for improving manufacturing and optimization of quantum products due to averaging noise effects, leading to incomplete understanding and suboptimal performance.

Innovation Solution

The method involves performing spectral quantum process tomography on qubit states to obtain eigenspectra, which are then used to determine crosstalk intensity between qubits, allowing for precise analysis and guidance in manufacturing and optimization processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional Clifford gates and randomized benchmark tests are used for crosstalk analysis, then the analysis process is simple, but the measurement precision and reliability are insufficient due to averaging noise effects

Engineering Contradiction:
Improvecrosstalk analysis precisionVSAvoidanalysis method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the fundamental parameters of the analysis method by using spectral quantum process tomography instead of conventional randomized benchmark tests. This involves transforming the analysis from averaging-based error rates to frequency-domain spectral analysis, enabling precise identification of crosstalk frequencies and their sources without the limitations of conventional approaches

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional mechanical approach of applying various Clifford gates with spectral quantum process tomography. This substitution eliminates the need for complex gate sequences and randomization, directly measuring the quantum process spectrum to identify crosstalk with higher precision and simpler methodology

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

2Reliability

If spectral quantum process tomography is performed to obtain detailed crosstalk intensity data, then the manufacturing and optimization guidance is improved, but the analysis time and computational resources increase

Engineering Contradiction:
Improvecrosstalk analysis reliabilityVSAvoidanalysis time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts only the essential spectral information needed for crosstalk identification from the quantum process tomography data. By focusing on the spectral components related to crosstalk frequencies rather than processing complete error rate data, the method achieves high reliability while reducing analysis time and computational overhead

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the crosstalk analysis into distinct spectral components, allowing separate identification and characterization of different crosstalk sources. This segmentation enables targeted analysis of specific frequency ranges and qubit interactions, improving reliability while optimizing analysis efficiency through selective processing

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11960973B2Method and apparatus for crosstalk analysis of qubits, computer device, and storage medium
Publication Date: 2024.04.16 TENCENT TECHNOLOGY (SHENZHEN) CO LTD
  • US11960973B2 patent drawing
  • US11960973B2 patent drawing
  • US11960973B2 patent drawing

AI summary

This application relates to a method for analyzing crosstalk between qubits, performed by a terminal. The method includes identifying a first qubit and a second qubit; performing spectral quantum process tomography on quantum states corresponding to the first qubit and the second qubit, to obtain a first eigenspectrum of a signal function corresponding to the first qubit and a second eigenspectrum of a signal function corresponding to the second qubit; performing spectral quantum process tomography on the quantum states corresponding to the first qubit and the second qubit, to obtain a third eigenspectrum of a common signal function of the first qubit and the second qubit; and determining a crosstalk intensity between the first qubit and the second qubit based on the first eigenspectrum, the second eigenspectrum, and the third eigenspectrum.