Qosy is a python package for constructing quantum operators with desired symmetry properties, which can include continuous or discrete symmetries.

Qosy provides a simple set of tools to

• specify a basis of Hermitian operators
• specify desired continuous symmetries represented by integrals of motion
• specify desired discrete symmetries represented by transformation rules
• generate all the Hermitian operators in the basis of operators with these symmetries

The tools can be used as either (1) a "forward method" to automatically generate the symmetries of a Hamiltonian or as (2) an "inverse method" to automatically construct Hamiltonians with desired symmetries.

Qosy requires the following software installed on your platform:

• Python
• Numpy
• Scipy
• If you want the visualization features: Matplotlib
• If you want to use the tutorial ipython notebooks: IPython
• If you want to build the documentation: Sphinx
• If you want to run the tests: pytest

To copy the development version of the code to your machine, type

git clone https://github.com/ClarkResearchGroup/qosy.git

To install, type

cd qosy
python setup.py install --user

or add the qosy folder to your PYTHONPATH environment variable.

To generate the documentation on your machine, type

cd qosy/docs
make html

To view it, type

firefox _build/html/index.html

To test Qosy after installation (recommended), type

cd qosy/tests
pytest

Some introductory ipython notebooks and scripts for generating results shown in [1] are available in the tutorials folder.

• Eli Chertkov

This project is licensed under the MIT License - see the LICENSE for details.

Based on work presented in

[1] E. Chertkov, B. Villalonga, and B. K. Clark, “Engineering Topological Models with a General-Purpose Symmetry-to-Hamiltonian Approach,” Phys. Rev. Research 2, 023348 (2020).