Talk:Controlled NOT gate

Ignores superposition of the control qbit[edit]

This article is kind of confusing because it considers the 0/1 cases of the control qbit distinctly like a classic logic gate and ignores superposition of it. --75.243.59.26 (talk) 00:08, 27 January 2012 (UTC)[reply]

Agreed. I've added a section on viewing the gate from the Hadamard basis. DavidBoden (talk) 13:34, 13 November 2014 (UTC)[reply]

False universality[edit]

Further, we can construct an AND GATE by using two CNOTs.

I see no (classical) way to do that, and that is why there is a Toffoli gate which is universal and reversible. — Preceding unsigned comment added by Alexandre Isoard (talk • contribs) 13:19, 11 March 2012 (UTC)[reply]

Proof section is strange[edit]

Why prove how the operator acts on something when it is defined by its action? And then go on to "prove" it through computation of the matrix-vector problem. A more interesting "proof" would be why the matrix has its particular representation. — Preceding unsigned comment added by 99.149.190.128 (talk) 04:15, 20 May 2012 (UTC)[reply]

Agreed. I've removed the entire section. DavidBoden (talk) 22:40, 14 February 2015 (UTC)[reply]

Practical section[edit]

An experimental section on how to create such a gate with quantum mechanics is needed. For the proof, it is enough for me, it just has the good solution before we search it, but it prooves it correctly fits to the definition of a C gate.

Proposed merge with C-ROT gate[edit]

Not enough differences from the CNOT article, or enough content to justify separate articles. ^Falling_Gravity 22:32, 31 January 2018 (UTC)[reply]

Matrix examples of cNOT in operation[edit]

OK -- I just needed to come to grips with the meanings of the entries in the state vector. 118.209.183.247 (talk) 01:36, 13 January 2019 (UTC)johnjPerth[reply]

Thank you 118.209.183.247 (talk) 10:16, 12 January 2019 (UTC)johnjPerth[reply]

Don't CNOT gates predate quantum computers?[edit]

I remember hearing about CNOT gates in one of the Feynman books, I think -- granted, he's given a lot of credit for quantum computing (perhaps too much, but that's neither here nor there), but it certainly predated any talk of qbits and such, and he talked about it as if it was already quite familiar. This article seems to only talk about in terms of their modern uses for building quantum computers. — Preceding unsigned comment added by Schnitzi (talk • contribs) 21:28, 24 April 2019 (UTC)[reply]

The CNOT gate is also possible to implement, and very-very likely was first implemented, as a classic gate for reversible computation. I added a sentence about this in the intro. · · · Omnissiahs hierophant (talk) 10:27, 19 April 2021 (UTC)[reply]