MQT QCEC - A tool for Quantum Circuit Equivalence Checking

MQT QCEC is an open-source C++20 and Python library for quantum circuit equivalence checking developed as part of the Munich Quantum Toolkit (MQT).

This documentation provides a comprehensive guide to the MQT QCEC library, including installation instructions, a quickstart guide, and detailed API documentation. The source code of MQT QCEC is publicly available on GitHub at munich-quantum-toolkit/qcec, while pre-built binaries are available via PyPI for all major operating systems and all modern Python versions. MQT QCEC is fully compatible with Qiskit 1.0 and above.

User Guide

• Installation
  • Building from Source for Performance
  • Integrating MQT QCEC into Your Project
  • Development Setup
• Quickstart
• Quantum Circuit Equivalence Checking
  • Construction Equivalence Checker (using Decision Diagrams)
  • Alternating Equivalence Checker (using Decision Diagrams)
  • Simulation Equivalence Checker (using Decision Diagrams)
  • ZX-Calculus Equivalence Checker
  • Resulting Equivalence Checking Flow
• Verifying the Results of Compilation Flows
  • Quantum Circuit Compilation
  • Using QCEC to Verify Compilation Flow Results
• Verifying Parameterized Quantum Circuits
  • Variational Quantum Algorithms
  • Equivalence Checking of Parameterized Quantum Circuits
  • Using QCEC to Verify Parameterized Quantum Circuits
• Partial Equivalence Checking
  • Partial Equivalence vs. Total Equivalence
  • Checking Partial Equivalence of Quantum Circuits
  • Using QCEC to Check for Partial Equivalence
• References
• Changelog
  • Unreleased
  • 3.5.0 - 2026-02-02
  • 3.4.0 - 2026-01-13
  • 3.3.0 - 2025-10-14
  • 3.2.0 - 2025-08-01
  • 3.1.0 - 2025-07-11
  • 3.0.0 - 2025-05-05
  • 2.8.2 - 2025-02-18
• Upgrade Guide
  • Unreleased
  • 3.5.0
  • 3.4.0
  • 3.3.0
  • 3.2.0
  • 3.1.0
  • 3.0.0

Developers

• Contributing
• AI Usage Guidelines
• Tooling
• Support

Contributors and Supporters

The Munich Quantum Toolkit (MQT) is developed by the Chair for Design Automation at the Technical University of Munich and supported by the Munich Quantum Software Company (MQSC). Among others, it is part of the Munich Quantum Software Stack (MQSS) ecosystem, which is being developed as part of the Munich Quantum Valley (MQV) initiative.

Thank you to all the contributors who have helped make MQT QCEC a reality!

The MQT will remain free, open-source, and permissively licensed—now and in the future. We are firmly committed to keeping it open and actively maintained for the quantum computing community.

To support this endeavor, please consider:

• Starring and sharing our repositories: https://github.com/munich-quantum-toolkit

• Contributing code, documentation, tests, or examples via issues and pull requests

• Citing the MQT in your publications (see References)

• Using the MQT in research and teaching, and sharing feedback and use cases

• Sponsoring us on GitHub: https://github.com/sponsors/munich-quantum-toolkit