${\rm qCH_{eff}}$ (/kju ʃɛf/) calculates effective Hamiltonians for quantum systems.

${\rm qCH_{eff}}$ can be installed using pip:

pip install qcheff

Detailed installation instruction are provided here. CuPy is required in order to use the GPU for computations.

We use the permissive MIT license. Pull requests are welcome. For major changes, please open a GitHub issue first to discuss what you would like to change. Please make sure to update tests as appropriate. More developer documentation is available here.

If you use ${\rm qCH_{eff}}$ in your work, please cite our paper:

@article{qcheff2025,
      title={GPU-accelerated Effective Hamiltonian Calculator}, 
      author={Abhishek Chakraborty and Taylor L. Patti and Brucek Khailany and Andrew N. Jordan and Anima Anandkumar},
      year={2025},
      eprint={2411.09982},
      archivePrefix={arXiv},
      primaryClass={quant-ph},
      url={https://arxiv.org/abs/2411.09982}, 
}