Introduction

Overview

QDecomp is a standalone software package to perform multiple decompositions of single-qubit and two-qubit quantum gates.

The package primarily focuses on decomposing gates into the Clifford+T universal subset by implementing the algorithm proposed by Ross and Selinger [Ross and Selinger, 2014].

The package contains 4 main subpackages:

decompositions : Proposes user-oriented functions for decomposing various quantum gates
utils : Contains the core algorithms and additional utility functions
rings : Implements classes for symbolic calculations in mathematical rings
plot : Offers visualization tools of core parts of the algorithm used mainly for debugging

Below is a figure illustrating the subpackages (green) and their associated modules (yellow) and classes (orange).

package_structure — `QDecomp` package structure

Documentation

The complete API documentation is available and can be built locally using Sphinx:

cd docs
make html
./build/html/index.html

The documentation is generated in docs/build/html/. Open docs/build/html/index.html in a browser to view it.

License

Released under the Apache License 2.0.

Collaborations

This package was made in collaboration with D-Wave and Polytechnique Montréal.

Citing This Package

If you use QDecomp in your research or projects, please cite it using the following BibTeX entry:

@software{qdecomp,
  author = {Romain, Olivier and Girouard, Vincent and Trudeau, Marius and Blais, Francis},
  title = {QDecomp},
  year = {2025},
  version = {1.1.0},
  url = {https://github.com/polyquantique/QDecomp}
}

References

[Cro24]

G. E. Crooks. Quantum Gates. 2024. URL: https://threeplusone.com/pubs/on_gates.pdf.

[KMM13]

Vadym Kliuchnikov, Dmitri Maslov, and Michele Mosca. Fast and efficient exact synthesis of single qubit unitaries generated by clifford and t gates. Quantum Information & Computation, 2013. URL: https://arxiv.org/abs/1206.5236.

[RS14]

N. J. Ross and P. Selinger. Optimal ancilla-free clifford+t approximation of z-rotations. Quantum Information & Computation, 2014. URL: https://arxiv.org/abs/1403.2975.