LAS-VQE

This code performs GB-LAS-UCC and DI-LAS-UCC calculations.

Requires:

1. Qiskit
2. Qiskit Nature (version < 0.5)
3. PySCF
4. MRH (github.com/MatthewRHermes/mrh)

GB-LAS-UCC steps:

1. Run qpe.py to obtain the ground state for each fragment, stored in qpe_state.npy
2. Run las-vqe.py using the initialize step, loading wave functions from qpe_state.npy

DI-LAS-UCC steps:

1. Run las-vqe.py using the initialize step and get_so_ci_vector()

HF-UCC steps:

1. Run las-vqe.py using the initialize step and the HartreeFock initial state