Update 02_gradients_framework.ipynb

[pearcandy]

Typo correction

removal of "\partial" in the second term on the right-hand side

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[Eric-Arellano]

Hi! Thanks for the contribution. What is the motivation for this change?

[pearcandy]

I am new to quantum computation and was just learning about gradients. At the time, I felt that I did not need the partial symbol on the right side in the finite difference formula. If I am wrong, please ignore my pull request.

[Eric-Arellano]

Okay, thanks. I'm going to assume that the original author and code reviewers were correct in having it, then.

In the future, when making contributions, it is helpful to put in the PR description what the motivation for the change is. If you're not sure whether a change is good or not, either don't open it or ask for feedback, e.g. by opening a GitHub issue or using the project's Slack.

Cheers in your quantum computing journey!

[pearcandy]

Thanks for your advice. Next time, I will try to discuss on Slack projects.

In this issue, I think the symbol for partial on the right-hand side in the equation, i.e., \partial \langle \psi(\theta..., does not make sense mathematically. This is because the equation implies rewriting the continuous derivative with respect to ε into a discrete numerical derivative. Nevertheless, the sign of the partial derivative remains on the right-hand side, which is obviously not correct. It is clear from a comparison with the formula for Parameter Shift Gradients discussed above in this chapter.

[Eric-Arellano]

Ah, I realize either way, opflow is deprecated and will soon be removed, per Qiskit/qiskit#10666. (We're still working out the specific plan to remove them)

Thank you again for the contribution!