Overlap of stabilizer states

[ghb24]

Thanks for the nice code.

I have a feature I am looking for - computing the overlap (not overlap squared / fidelity) between stabilizer states. Is this something that may be supported in the near future in PyClifford / something that it would be simple for me to hack in? As far as I can tell, the phase information on the overlap is not currently available in this code.

Many thanks.

[hongyehu]

Hi @ghb24, you are right. Currently, the phase information is not supported, and I think no other Clifford simulation package supports this as well. But this is a feature that I also want to add.
In order to do it, we need to implement other tools as well, such as canonical circuits to prepare stabilizer states. If this new feature is important to your research, I could try to do it within next 2 month in the next release.
Thank you for being interested in PyClifford!

[ghb24]

It's certainly something I'm keen to have for our own research purposes. Indeed, we already have this coded up, but its rather hacky and slow, hence looking around for a more efficient implementation -- as you say though, this doesn't seem to be implemented in packages as far as we can see, so would be a great (and unique) feature for PyClifford, that we would certainly have a lot of use for. We could also provide some code to compare against if useful. Let me know offline if you would like more information on this.