Code to accompany The minimal example of quantum network Bell nonlocality

Erwan Don, Jessica Bavaresco, Patryk Lipka-Bartosik, Nicolas Gisin, Nicolas Brunner, and Alejandro Pozas-Kerstjens

This is a repository containing the code used to compute the figures 3 and 4 of "The minimal example of quantum network Bell nonlocality". Erwan Don, Jessica Bavaresco, Patryk Lipka-Bartosik, Nicolas Gisin, Nicolas Brunner, and Alejandro Pozas-Kerstjens, arXiv:2605.00981." It provides the codes for proving the triangle nonlocality and for finding quantum realizations of noisy $W$ distributions. The part for nonlocality uses the fast-inflation implementation by Victor Gitton.

The code is written in Python (for finding the quantum models) and in C++ (for proving network nonlocality). The Python part requires numpy for math operations, scipy for the optimization engine, and matplotlib for plots. The nonlocality part requires Mosek as a solver for linear programs.

The network nonlocality part must be compiled. In order to do so, please follow the instructions in the fast-inflation documentation. However, the following should suffice:

cd nonlocality-detection
make prepare
make release

Then, in order to perform one of the tests, just run ./ release_inf w_(visibility). Further instructions can be found in the fast-inflation documentation.

The file quantum_realizations.ipynb is a Jupyter notebook that computes the parameters for our models in Fig. 3 ($p_{\varnothing}, p_0, \omega, \theta_0, \theta_1$) and the distances in Fig. 4 in the manuscript.

If you would like to cite this work, please use the following format:

@misc{don2026minimal,
  title = {The minimal example of quantum network {Bell} nonlocality},
  author = {Don, Erwan and Bavaresco, Jessica and Gisin, Nicolas and Brunner, Nicolas and Pozas-Kerstjens, Alejandro},
  archivePrefix = {arXiv},
  eprint = {2605.00981}
}