[DEMO] Perturbative Gadgets for Variational Quantum Algorithms

[SimonCichy]

General information

Name Simon Cichy.

Affiliation (optional) Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195 Berlin, Germany, Institute for Theoretical Physics, ETH Zürich, 8093 Zürich, Switzerland.

Twitter (optional) @sdcichy

Image (optional)

---

Demo information

Title Perturbative Gadgets for Variational Quantum Algorithms

Abstract In this tutorial, we will explore the application of perturbative gadgets in variational quantum algorithms. Substituting a global Hamiltonian with its gadgetized equivalent allows to train the algorithm on a local cost function and still finding the target minimum, thus avoiding the issue of cost function dependent barren plateaus.

Relevant links https://github.com/SimonCichy/barren-gadgets/tree/main/Pennylane-tutorial https://arxiv.org/pdf/2210.03099.pdf

[isaacdevlugt]

Thanks @SimonCichy ! Look forward to checking this out 👀

[KetpuntoG]

Hi @SimonCichy , great job! The demo is really well done 😄 If you like we could guide you to introduce it as a demo of the pennylane website with your name, instead of in the community demos section. This requires a bit more work and will take a bit more time but I wanted to tell you about the option in case you find it interesting 💪 If not, we will get on with the integration in the community section 🚀

[SimonCichy]

Hi @KetpuntoG, thanks a lot, it is nice to hear that 😄 And in principle, I would be happy to make it a demo of the pennylane website! If you can tell me a bit more about what it implies, what would have to be changed, etc, I could tell you if (or rather how quick) I can do it

[KetpuntoG]

The steps to write a demo in PennyLane can be found in the readme of the qml repo. The format of the demos are in .py using Sphinx. Having the notebook already made, we have a script (in the readme you will find it too) to facilitate the conversion. Then, it's just a matter of fixing small formatting details. Once you have it in demo format, we will do a more in-depth review of the content in which we will do a couple of interactions with you. Estimating more or less the time, from the moment you start building the demo until it goes through the review process, it could be a month. If you are in a hurry, we can always put the demo as a community demo and then, when you prefer, work on the PennyLane proper demo. How do you want to proceed? :)

[josh146]

@SimonCichy something to note is that our demos are not in the form of notebooks. Instead:

• They are executable python scripts
• The text describing the code is using restructuredText, not markdown

But there are nice ways to convert a notebook to this format. For example, you can export a notebook in rst format (and then manually change it to a python script) directly from Jupyter:

Alternatively, we have a script linked in the readme for converting jupyter notebooks.

[SimonCichy]

Thank you both! I am not in a hurry, and it does not seem to be all too much work, so I'm in. I will get working on converting the file and will let you know when it is done, or if I am having issues.

[SimonCichy]

I believe I have done the necessary changes, but I would be happy if you could confirm the next steps. I have now the qml repo locally and have added my tutorial in .py format in demonstrations. It runs the way it is supposed to, but I didn't know where to put the other files (where I define things which I did not want to go into detail in the tutorial itself). For now, I put them in the subfolder corresponding to the tutorial (where I also put the image from the tutorial). Is it fine like that? To check that everything is in order, I tried to build the website locally (running only my demo, as explained in the readme) but I am having issued with that. Should I still do the pull request as is?

[josh146]

@SimonCichy awesome to hear! Definitely feel free to open a PR, that is much easier than building the website locally.

When you create a PR, we have an automatic build system that will build the website, and create a link in the PR for you to view the changes. This preview will update with every push to the PR :)

[SimonCichy]

To be honest, it will be my first pull request, so could you confirm, that I am doing it right before I mess something up? (sorry) I cloned the repository, created a branch (local for now) and did my changes there. Do I push to make it a remote branch, and then proceed to making a PR from my (new) branch to the master branch? Thanks for the help...

[isaacdevlugt]

Yep! Just push your changes (git push --set-upstream origin <branch name>), then make a Pull Request 😄. The Pull Request will be for merging your branch with your demo into the master branch 🙂. See here for making a Pull Request! Let us know if you have any issues with that 🚀

[SimonCichy]

Thank you a lot. Apparently, I do not have the correct access rights, so I guess I am doing something wrong. When trying to set the upstream branch on the terminal, I get an error message

Permission denied (publickey).
fatal: Could not read from remote repository.      
Please make sure you have the correct access rights
and the repository exists

When doing it with my git GUI, after a few seconds the remote branch disappears and checking the status I get

Your branch is based on 'origin/demo_barren_gadgets', but the upstream is gone.

I will try to investigate what went wrong, but if it is a problem you are familiar with, I would appreciate some advice 😉

[KetpuntoG]

Hello @SimonCichy ! Probably, you tried to make a clone instead of the fork. In principle if you do the fork it shouldn't give you any problems and then you can do the PR in the same way :)

[isaacdevlugt]

🤦! Sorry about that @SimonCichy, should've known you wouldn't have had permissions.

As @KetpuntoG said, if you fork the repo, make your changes there, then make a PR from your fork, then you're all set!

Instructions here.

[SimonCichy]

Thank you a lot, again. Now there should be a pull request, but most of the checks were not successful. Does that mean something went wrong on my side?

[josh146]

@SimonCichy perfect, now we can jump into the PR and help troubleshoot :)

[KetpuntoG]

I close this issue, we are already working with the proper demo