Add a new SAOOVQE solver

[MartinBeseda]

I'm writing here with a question, as I'd like to submit a contribution to Qiskit Nature in the form of a new State-Averaged Orbital-Optimized VQE, containing also some new approach to orbital diabatization etc. But, as it is quite a large code, I didn't want to open a PR right away, as I'd like to ask, how should I proceed...

If I do understand the Nature's structure correctly, should we start with including it into second_q/algorithms/excited_states_solvers?

The repository of the whole code is here: https://gitlab.com/MartinBeseda/sa-oo-vqe-qiskit
And the documentation is online here: https://sa-oo-vqe-qiskit.readthedocs.io/en/latest/index.html

P.s.: Yes, I've read the contributing guidelines, we'll supplement CLAs, etc. right with the submission.

Thank you very much for all the opinions and advice!

[MartinBeseda]

@mrossinek Do you think it could be of interest to add our solver? Thank you for the info!

[MartinBeseda]

Dear @woodsp-ibm ,
is there any way we could proceed in this direction? If you're not accepting new solvers for now, I understand it. If you do, I'd like to know some requirements to fulfill.

Thank you very much for your advice!

[woodsp-ibm]

@MartinBeseda The main maintainers of Qiskit Nature are now Algorithmiq since end 2023, see https://medium.com/qiskit/a-new-chapter-for-qiskit-algorithms-and-applications-5baff541e826 My role is now pretty much just assist as/if needed for the new maintainers since I have been involved with this code since its creation. Any future work/features/releases is managed by the new maintainers. The last release was nearly a year ago and I do not what plans there are, if any, for this code going forwards,

[MartinBeseda]

@woodsp-ibm Thank you very much for explanation. Do you know about any contact person of Algorithmiq, whom I could ask about the involvement?

[woodsp-ibm]

There has been little to no activity here for a while and as the transition was some time ago I really do not know. At the time maintainers were added from Algorithmiq - see the approvers list in this PR #1374 - the latter 2. The best I can offer, sorry.