constantineroux / pgs

point group symmetries project

Tapering off qubits using the point group symmetries.

This repository contains the code based on qiskit for tapering off qubits using point group symmetries.

It uses qiskit-0.19.4 which can be installed by:

pip3 install qiskit==0.19.4

Python files

1. r_mat_for_mols.py contains the code for getting the Hamiltonian for a molecule and constructing the R matrices corresponding to the point group symmetries. It also contains the test code which verifies that the R matrices do commute with the Hamiltonian.
2. taper_qubit_rm_funcs.py contains the code that uses the matrices constructed in r_mat_for_mols.py to taper of the qubits. It contains all the helper functions. It main code has two cases for AO and MO basis.
3. symmetries.py contains the code for simultaneously diagonalizing the R matrices.

Jupyter Notebook

The demo jupyter notebook tapering_using_point_group_symmetries.ipynb provides a step by step process for tapering off qubits using the point group symmetries. The code follows the process/algorithm given in https://arxiv.org/abs/1910.14644