Talk:Quantum phase estimation algorithm

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New Section[edit]

Soon I'm going to make a major upgrade to this article. You can see the expected version under User:Omrika/sandbox/QIP/Quantum_phase_estimation, still without references but with major changes and additions. Any comments? Omrika (talk) 16:50, 30 December 2016 (UTC)[reply]

I'm not a fan of this "C-U" notation. Older versions of the article didn't have it. I haven't seen it in any other quantum computing literature. I didn't know what C-U was until I figured out that it is not supposed to be "C minus U". I recommend reverting back to the old style as the controlled nature of the unitary is already given by the circuit diagram. The redundant information only adds confusion. — Preceding unsigned comment added by 202.66.60.168 (talk) 17:13, 27 January 2017 (UTC)[reply]

I agree that the "C" should go: the standard depiction of a controlled-U gate is the bullet connected to a box labeled "U" and the present notation is misleading. --Qcomp (talk) 16:17, 28 January 2017 (UTC)[reply]

Agreed.--Robin (talk) 21:02, 20 May 2018 (UTC)[reply]

Image[edit]

In the image of the circuit, it should be "QFT_{2^n}" not "QFT_n". — Preceding unsigned comment added by 2607:9880:1A17:FFE2:305B:9CC1:77FC:E0D2 (talk) 02:48, 12 March 2019 (UTC)[reply]

As long as the article is consistent, the current notation, QFT_n, is not wrong. From a cursory look at other sources it seems that the n dependence is often omitted altogether (for example it is on Nielsen and Chuang), so I don't see it as particularly troublesome to use QFT_n here (also, changing it would require recreating the image). — Preceding unsigned comment added by Luca Innocenti (talk • contribs) 11:33, 12 March 2019 (UTC)[reply]

|sin(x)| < |x|[edit]

Hello!

I may be missing something painfully obvious, but under the section Measurement we have

$|\sin(\pi \delta )|\leqslant |\pi \delta |{\text{ for }}|\delta |\leqslant {\frac {1}{2^{n+1}}}$

Doesn't $|\sin(x)|\leqslant |x|$ generally hold? Why the constraint on $\pi \delta$ ?

Miguelmurca (talk) 15:06, 13 March 2019 (UTC)[reply]

Rename to "Quantum phase estimation"[edit]

I believe that the article should be renamed to "Quantum phase estimation". The 'algorithm' in the name is kind of redundant, and most sources call it "Quantum phase estimation" or "phase estimation" anyways (e.g. Nielsen and Chuang, Watrous' lecture notes https://cs.uwaterloo.ca/~watrous/QC-notes/). Is there consensus to do so? Tapeworms27 (talk) 13:49, 15 April 2023 (UTC)[reply]