OpenFermion is an open source effort for compiling and analyzing quantum algorithms to simulate fermionic systems, including quantum chemistry. Among other functionalities, the current version features data structures and tools for obtaining and manipulating representations of fermionic and qubit Hamiltonians. For more information, see our release paper and press release about the project.

Installing OpenFermion requires pip. Make sure that you are using an up-to-date version of it. For information about getting started beyond what is provided below please see intro and code examples. Also take a look at the ipython notebook demo as well as our detailed code documentation.

Currently, OpenFermion is only tested on Mac and Linux for the reason that both electronic structure plugins are only compatible with Mac and Linux. However, for those who would like to use Windows, or for anyone having other difficulties with installing OpenFermion or its plugins, we have provided a Docker image and usage instructions in the docker folder. The Docker image provides a virtual environment with OpenFermion and select plugins pre-installed. The Docker installation should run on any operating system.

To install the latest version of OpenFermion (in development mode):

git clone https://github.com/quantumlib/OpenFermion
cd OpenFermion
python -m pip install -e .

To install the latest PyPI release as a library (in user mode):

python -m pip install --user openfermion

OpenFermion relies on modular plugin libraries for significant functionality. Specifically, plugins are used to simulate and compile quantum circuits and to perform classical electronic structure calculations. Follow the links below to learn more about these useful plugins.

• OpenFermion-ProjectQ to support integration with ProjectQ.
• Forest-OpenFermion to support integration with Forest.

• OpenFermion-Psi4 to support integration with Psi4 (recommended).
• OpenFermion-PySCF to support integration with PySCF.

We'd love to accept your contributions and patches to OpenFermion. There are a few small guidelines you need to follow. Contributions to OpenFermion must be accompanied by a Contributor License Agreement. You (or your employer) retain the copyright to your contribution, this simply gives us permission to use and redistribute your contributions as part of the project. Head over to https://cla.developers.google.com/ to see your current agreements on file or to sign a new one.

All submissions, including submissions by project members, require review. We use GitHub pull requests for this purpose. Consult GitHub Help for more information on using pull requests. Furthermore, please make sure your new code comes with extensive tests! We use automatic testing to make sure all pull requests pass tests and do not decrease overall test coverage by too much. Make sure you adhere to our style guide. Just have a look at our code for clues. We mostly follow PEP 8 and use the corresponding linter to check for it. Code should always come with documentation, which is generated automatically and can be found here.

Ryan Babbush (Google), Jarrod McClean (Google), Ian Kivlichan (Harvard), Damian Steiger (ETH Zurich), Dave Bacon (Google), Yudong Cao (Harvard), E. Schuyler Fried (Harvard), Craig Gidney (Google), Thomas Häner (ETH Zurich), Vojtĕch Havlíček (Oxford), Zhang Jiang (NASA), Matthew Neeley (Google), Jhonathan Romero (Harvard), Nicholas Rubin (Rigetti), Daniel Sank (Google), Nicolas Sawaya (Harvard), Kanav Setia (Dartmouth), Hannah Sim (Harvard), Wei Sun (Google) and Kevin Sung (University of Michigan).

When using OpenFermion for research projects, please cite:

Jarrod R. McClean, Ian D. Kivlichan, Damian S. Steiger, Yudong Cao, E. Schuyler Fried, Craig Gidney, Thomas Häner, Vojtĕch Havlíček, Zhang Jiang, Matthew Neeley, Jhonathan Romero, Nicholas Rubin, Nicolas P. D. Sawaya, Kanav Setia, Sukin Sim, Wei Sun, Kevin Sung and Ryan Babbush. OpenFermion: The Electronic Structure Package for Quantum Computers. arXiv:1710.07629. 2017.

We are happy to include future contributors as authors on later releases.

Copyright 2017 The OpenFermion Developers. This is not an official Google product.