Add Qiskit example on mitigating the energy landscape of a variational circuit

[nickdgardner]

Description

Resolves #1334. Makes a Qiskit version of the tutorial Mitigating the energy landscape of a variational circuit with Mitiq.

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License

• [x] I license this contribution under the terms of the GNU GPL, version 3 and grant Unitary Fund the right to provide additional permissions as described in section 7 of the GNU GPL, version 3.

Before opening the PR, please ensure you have completed the following where appropriate.

• [x] I added unit tests for new code.
• [x] I used type hints in function signatures.
• [x] I used Google-style docstrings for functions.
• [x] I updated the documentation where relevant.
• [x] Added myself / the copyright holder to the AUTHORS file

[github-actions[bot]]

:point_left: Launch a binder notebook on branch nickdgardner/mitiq/master

[codecov[bot]]

Codecov Report

Merging #1551 (ac0fc26) into master (38b6a9c) will not change coverage. The diff coverage is n/a.

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  Files          63       63           
  Lines        2921     2921           
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  Hits         2869     2869           
  Misses         52       52           

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[nickdgardner]

@natestemen Ok it should be good to go!

Along with making the changes necessary for the new qiskit example to show up on the gallery, I made the following additional changes which I thought would be helpful (but if not obviously they can be discarded!):

To make the original cirq example more consistent with the new qiskit example, as well as with the future pennylane and braket examples, I made these changes

• in examples.myst, change title to "Using ZNE to compute the energy landscape of a variational circuit with Cirq"
• in _thumbnails/ and conf.py, change thumbnail to a version that includes the Cirq logo

Toward the end of maintaining consistent thumbnail format as we add more examples from various frontends, I thought it would be helpful to have a set of canonical images for frontend logos. So I made this change

• in _thumbnails/, add a folder frontend-logos/ which contains .png files for cirq, qiskit, pennylane, and braket logos

If any of the additional changes should be discarded or edited, just let me know and I can update the PR.

[Rahul-Mistri]

Happy with the built doc! Everything looks good to me, great job Nick! Just one thing to follow up during the meeting - but after that should be good to go.

[nickdgardner]

@Rahul-Mistri @natestemen Ok I think "simple_landscape" is now renamed everywhere it needs to be.

One question: In my local copy of the Mitiq repository, the name "simple_landscape" also occurs (see below) in docs/jupyter_execute/examples/, but the folder jupyter_execute/ doesn't seem to exist on my fork on github (where I was making the renaming changes), so I didn't change these occurrences. I'm guessing jupyter_execute/ is somehow generated automatically? Is it ok to leave these unchanged?

docs/jupyter_execute/examples/simple_landscape.ipynb docs/jupyter_execute/examples/simple_landscape.py docs/jupyter_execute/examples/simple_landscape_13_0.png docs/jupyter_execute/examples/simple_landscape_17_0.png docs/jupyter_execute/examples/simple_landscape_23_0.png

[Rahul-Mistri]

@nickdgardner it shouldn't be an issue. I'd recommend pulling from your fork to update your local repo and rebuilding docs. It should resolve everything.

[nickdgardner]

@Rahul-Mistri That fixed everything. Thanks!

[natestemen]

BTW Nick, I plan to do a release tomorrow (Oct 31 🎃). If you aren't able to do these changes soon (sorry for the late comments), I'll make them and push them up to you branch before I merge it.

[nickdgardner]

@andreamari @natestemen Thanks for the edits, and for the heads-up about the release! I'll get these done at some point within the next hour.

[natestemen]

The build is failing, but with expected errors due to a link renaming, and a flaky test which is being tracked in https://github.com/unitaryfund/mitiq/issues/1509.