MQT YAQS: A Tool for Simulating Open Quantum Systems, Noisy Quantum Circuits, and Realistic Quantum Hardware

YAQS (pronounced "yaks" like the animals) is a Python library, primarily focused on simulating open quantum systems, noisy quantum circuits, and designing realistic quantum hardware.

YAQS is part of the Munich Quantum Toolkit (MQT) developed by the Chair for Design Automation at the Technical University of Munich.

If you have any questions, feel free to create a discussion or an issue on GitHub.

Features

• Simulation of Open Quantum Systems: Simulate large-scale open quantum systems with a paralellized implementation using the Tensor Jump Method (TJM) (Large-scale stochastic simulation of open quantum systems)
• Equivalence Checking of Quantum Circuits: Check the equivalence or non-equivalence of quantum circuits with a scalable MPO-based method (Equivalence Checking of Quantum Circuits via Intermediary Matrix Product Operator)
• Noisy Quantum Circuit Simulation: Investigate the effect of noise on large quantum circuits

Upcoming Features (Check back soon)

• WIP: Quantum Hardware Design: Design better quantum hardware with realistic simulation methods

Getting Started

1. Clone this repository:

   git clone https://github.com/aaronleesander/YAQS.git
   cd yaqs

2. Create and activate a virtual environment:

On macOS/Linux

python -m venv venv
source venv/bin/activate

On Windows (PowerShell)

python -m venv venv
.\venv\Scripts\activate.ps1

3. Install YAQS in editable mode so that your changes appear immediately:

pip install -e .

4. Check the yaqs/examples folder for usage details.

Contributing

Fork the repository and clone your fork. Create a new branch for your changes. Commit and push your work, then open a Pull Request.

Citations

In case you are using MQT YAQS in your work, we would be thankful if you referred to it by citing the relevant publications:

@misc{sander2025_TJM,
      title={Large-scale stochastic simulation of open quantum systems}, 
      author={Aaron Sander and Maximilian Fröhlich and Martin Eigel and Jens Eisert and Patrick Gelß and Michael Hintermüller and Richard M. Milbradt and Robert Wille and Christian B. Mendl},
      year={2025},
      eprint={2501.17913},
      archivePrefix={arXiv},
      primaryClass={quant-ph},
      url={https://arxiv.org/abs/2501.17913}, 
}
@misc{sander2024_equivalencechecking,
      title={Equivalence Checking of Quantum Circuits via Intermediary Matrix Product Operator}, 
      author={Aaron Sander and Lukas Burgholzer and Robert Wille},
      year={2024},
      eprint={2410.10946},
      archivePrefix={arXiv},
      primaryClass={quant-ph},
      url={https://arxiv.org/abs/2410.10946}, 
}

Acknowledgements

This work received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 101001318) and Millenion, grant agreement No. 101114305). This work was part of the Munich Quantum Valley, which is supported by the Bavarian state government with funds from the Hightech Agenda Bayern Plus, and has been supported by the BMWK on the basis of a decision by the German Bundestag through project QuaST, as well as by the BMK, BMDW, and the State of Upper Austria in the frame of the COMET program (managed by the FFG).