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The article asserts that along with a couple of other gates form a "universal" set of gates. What is the significance and/or derivation of 3/5? Would other angles work as well? What is the critical property of the particular angle? -- David Battle 01:39, 18 August 2005 (UTC)
Rotating about x axis:
Rotating about y axis:
Rotating about z axis:
http://jquantum.sourceforge.net/jQuantumApplet.html
concerning articles :1:Quantum gate, 2:Quantum Gate and 3:Quantum Gate (PC game) previously, 3 redirected to 2 which held the info about the game, which i thought was very confusing, as it was clear to me that 2 should redirect to 1, with 3 holding the information about the game, so i moved the game information from 2 to 3, and redirected 2 to one, this will be coppied on the other two articles' talk page 193.60.83.241 ( talk) 11:47, 14 May 2008 (UTC)
The section in the article which claims to demonstrate how a NAND quantum gate could be physically realised is most strange, because the "NAND gate" produced at the end is not invertible, thus not unitary, and hence not a quantum gate at all! Indeed, if the "gate" produced existed at all, it could be used to create copies of the state of qubits, blatantly violating the no-cloning theorem. However, I'm not sufficiently versed in the electrodynamics to tell whether the whole thing is just nonsense, or perhaps rather a poorly remembered example that was really supposed to produce some other classical gate, such as CNOT. 81.170.129.141 ( talk) 23:34, 1 February 2013 (UTC)
Do the logic gates allow superpositional values to act as operators or instructions? If they do, that's not really coming through in the article. If they do not, then is this a fundamental limitation of the quantum phenomena, or is it just much simpler to build a QC with "ordinary" logic gates? While the answers to these questions might turn out to be rather awkward, I think they'd go a long way to making the idea of quantum computing more accessible to a larger number of people. Thank you! -- 17:38, 22 April 2014 (UTC) — Preceding unsigned comment added by TheLastWordSword ( talk • contribs)
Assume Deutsch gates are permitted to take an arbitrary rotation as parameter, e.g. set via a potentiometer-like control attached to each Deutsch gate that can be rotated smoothly about 360 degrees when manually constructing the circuit. Presumably this would permit realizing any unitary operation on n qubits with finitely many quantum gates.
As a function of n, what is the minimum number of Deutsch gates needed to be sure of being able to implement any unitary operation?
It seems likely this has already been determined. If so this section of the article should say something about it. Vaughan Pratt ( talk) 18:09, 1 December 2015 (UTC)
Where can I learn about physically realizations of these various gates?
Meekohi ( talk) 21:01, 2 December 2019 (UTC)
The section on Unitary inversion of gates claims that the Pauli Y gate is not Hermitian. The Pauli Y gate is Hermitian because the Pauli y matrix/operator is hermitian (as are all the Pauli matrices). I have edited the page to give the Ising (XX) gate instead as an example. 65.130.201.235 ( talk) 19:33, 9 February 2020 (UTC)
The top of the article has a Template:More citations needed but the article has already many references. It would be better if we could have in-line templates or specific templates per section.-- ReyHahn ( talk) 18:31, 10 May 2021 (UTC)
The end of the article kindof ends with something that looks more like a tutorial than anything else. This article feels like it's about 10x easier to read than most books on the subject. I really like that :D Not sure that it is "the wikipedia way" though. · · · Omnissiahs hierophant ( talk) 23:51, 13 May 2021 (UTC)
I was the one that expanded on the Ising gates and the related complex SWAPs. But maybe it makes the section of the gates longer and does not really add to it. Also we do not have a circuit representation for those gates. Should we remove them from the article for better fluidity?-- ReyHahn ( talk) 20:09, 6 August 2021 (UTC)
Is there any reason the Mølmer–Sørensen gate is excluded in this article? There being no objections I could write up a section on MS gates. — Preceding unsigned comment added by Andrewvh4 ( talk • contribs) 19:15, 11 October 2021 (UTC)
I deleted this section:
A controlled function or gate behaves conceptually differently depending on whether one approaches it from before measurement, or after measurement:
End of quote.
I began writing this section, didn't add any real sources for the actual if-statement, but only for quantum parallelism. Then it morphed away as stuff sometimes do on wikipedia, and now I am no longer sure how true the 2nd half of the 2nd bullet is.
The sources (esp. Ömer) has good examples for what "quantum-if" are, and how they differ from normal if's.
References
Should we make a separate article i.e. List of quantum logic gates? that way we could focus on a few main ones here and add even more in the new article. Note that the article is reaching 100 kB of WP:readable prose so it is suggested to be split.-- ReyHahn ( talk) 15:30, 5 September 2022 (UTC)
@ Omnissiahs hierophant: Here is draft of the article in question User:ReyHahn/List_of_quantum_logic_gates. Comments are welcome. Note that I removed most of the comments on the Clifford gates as those, Toffoli and controlled gates should remain in the article.-- ReyHahn ( talk) 17:31, 10 September 2022 (UTC) And for the Grover diffusor we could include a section of algorithm-based gates with names but not necessarily with matrix representation.-- ReyHahn ( talk) 19:33, 10 September 2022 (UTC)
Maybe it is that. I just like minimal set gates with no continuous parameters (also gates with names). BTW Mølmer-Sørensen gate is defined as a non-parametrized gate in the wiki article, but in some other articles it has an angle. What's up with that? Any good ref?-- ReyHahn ( talk) 15:29, 14 September 2022 (UTC) I am under the impression that there is a difference between the MG gate and the general MG gates.-- ReyHahn ( talk) 15:41, 14 September 2022 (UTC)
Global phase is weird. I am starting to think that maybe I have been wrong about it even existing, doubting myself. But, in the books they kindof say that it does exist. For example, by saying that gates belong to U(2), and not SU(2). They also reference it by including it in factorizations.. But, however, IBM says that the Hamiltonian for it is useless ( link).
It has to exist, otherwise single-qubit gates would not belong to U(2), but SU(2). And intuitively (although I have not tested this), if one inverts the global phase early in the Grover's algorithm, then that would cause the algorithm amplify (with Grover's diffusion operator) all the wrong values, instead of the correct value(s) - essentially inverting the search query.
Why are people suggesting global phase does not exist?? Is it because it does not matter at all in normal quantum physics? · · · Omnissiahs hierophant ( talk) 16:10, 20 January 2023 (UTC)
I am pretty lay when it comes to the math behind quantum mechanics. I think a lot of people may have an interest in stuff like this. However, in just a few paragraphs the article jumps into things that only physics grads are going to understand. It would be nice if there was some more general and less intimidating information about how this works and its applications. The kinds of info a lay person could understand. As I understand it this page should really just describe what a Q logic gate is and how they can be applied. There should be another page with types of gates and the more complex descriptions of the mathematical formulas. I imagine that your average person reads of few lines on this page and gives up right away. Since this is an encyclopedia, it should contain the simplest way to understand how things work alongside the complex information. Thanks 162.246.112.154 ( talk) 19:51, 21 April 2024 (UTC)
Cite error: There are <ref group=lower-alpha>
tags or {{efn}}
templates on this page, but the references will not show without a {{reflist|group=lower-alpha}}
template or {{notelist}}
template (see the
help page).
![]() | This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
![]() | Graphs are unavailable due to technical issues. There is more info on Phabricator and on MediaWiki.org. |
The article asserts that along with a couple of other gates form a "universal" set of gates. What is the significance and/or derivation of 3/5? Would other angles work as well? What is the critical property of the particular angle? -- David Battle 01:39, 18 August 2005 (UTC)
Rotating about x axis:
Rotating about y axis:
Rotating about z axis:
http://jquantum.sourceforge.net/jQuantumApplet.html
concerning articles :1:Quantum gate, 2:Quantum Gate and 3:Quantum Gate (PC game) previously, 3 redirected to 2 which held the info about the game, which i thought was very confusing, as it was clear to me that 2 should redirect to 1, with 3 holding the information about the game, so i moved the game information from 2 to 3, and redirected 2 to one, this will be coppied on the other two articles' talk page 193.60.83.241 ( talk) 11:47, 14 May 2008 (UTC)
The section in the article which claims to demonstrate how a NAND quantum gate could be physically realised is most strange, because the "NAND gate" produced at the end is not invertible, thus not unitary, and hence not a quantum gate at all! Indeed, if the "gate" produced existed at all, it could be used to create copies of the state of qubits, blatantly violating the no-cloning theorem. However, I'm not sufficiently versed in the electrodynamics to tell whether the whole thing is just nonsense, or perhaps rather a poorly remembered example that was really supposed to produce some other classical gate, such as CNOT. 81.170.129.141 ( talk) 23:34, 1 February 2013 (UTC)
Do the logic gates allow superpositional values to act as operators or instructions? If they do, that's not really coming through in the article. If they do not, then is this a fundamental limitation of the quantum phenomena, or is it just much simpler to build a QC with "ordinary" logic gates? While the answers to these questions might turn out to be rather awkward, I think they'd go a long way to making the idea of quantum computing more accessible to a larger number of people. Thank you! -- 17:38, 22 April 2014 (UTC) — Preceding unsigned comment added by TheLastWordSword ( talk • contribs)
Assume Deutsch gates are permitted to take an arbitrary rotation as parameter, e.g. set via a potentiometer-like control attached to each Deutsch gate that can be rotated smoothly about 360 degrees when manually constructing the circuit. Presumably this would permit realizing any unitary operation on n qubits with finitely many quantum gates.
As a function of n, what is the minimum number of Deutsch gates needed to be sure of being able to implement any unitary operation?
It seems likely this has already been determined. If so this section of the article should say something about it. Vaughan Pratt ( talk) 18:09, 1 December 2015 (UTC)
Where can I learn about physically realizations of these various gates?
Meekohi ( talk) 21:01, 2 December 2019 (UTC)
The section on Unitary inversion of gates claims that the Pauli Y gate is not Hermitian. The Pauli Y gate is Hermitian because the Pauli y matrix/operator is hermitian (as are all the Pauli matrices). I have edited the page to give the Ising (XX) gate instead as an example. 65.130.201.235 ( talk) 19:33, 9 February 2020 (UTC)
The top of the article has a Template:More citations needed but the article has already many references. It would be better if we could have in-line templates or specific templates per section.-- ReyHahn ( talk) 18:31, 10 May 2021 (UTC)
The end of the article kindof ends with something that looks more like a tutorial than anything else. This article feels like it's about 10x easier to read than most books on the subject. I really like that :D Not sure that it is "the wikipedia way" though. · · · Omnissiahs hierophant ( talk) 23:51, 13 May 2021 (UTC)
I was the one that expanded on the Ising gates and the related complex SWAPs. But maybe it makes the section of the gates longer and does not really add to it. Also we do not have a circuit representation for those gates. Should we remove them from the article for better fluidity?-- ReyHahn ( talk) 20:09, 6 August 2021 (UTC)
Is there any reason the Mølmer–Sørensen gate is excluded in this article? There being no objections I could write up a section on MS gates. — Preceding unsigned comment added by Andrewvh4 ( talk • contribs) 19:15, 11 October 2021 (UTC)
I deleted this section:
A controlled function or gate behaves conceptually differently depending on whether one approaches it from before measurement, or after measurement:
End of quote.
I began writing this section, didn't add any real sources for the actual if-statement, but only for quantum parallelism. Then it morphed away as stuff sometimes do on wikipedia, and now I am no longer sure how true the 2nd half of the 2nd bullet is.
The sources (esp. Ömer) has good examples for what "quantum-if" are, and how they differ from normal if's.
References
Should we make a separate article i.e. List of quantum logic gates? that way we could focus on a few main ones here and add even more in the new article. Note that the article is reaching 100 kB of WP:readable prose so it is suggested to be split.-- ReyHahn ( talk) 15:30, 5 September 2022 (UTC)
@ Omnissiahs hierophant: Here is draft of the article in question User:ReyHahn/List_of_quantum_logic_gates. Comments are welcome. Note that I removed most of the comments on the Clifford gates as those, Toffoli and controlled gates should remain in the article.-- ReyHahn ( talk) 17:31, 10 September 2022 (UTC) And for the Grover diffusor we could include a section of algorithm-based gates with names but not necessarily with matrix representation.-- ReyHahn ( talk) 19:33, 10 September 2022 (UTC)
Maybe it is that. I just like minimal set gates with no continuous parameters (also gates with names). BTW Mølmer-Sørensen gate is defined as a non-parametrized gate in the wiki article, but in some other articles it has an angle. What's up with that? Any good ref?-- ReyHahn ( talk) 15:29, 14 September 2022 (UTC) I am under the impression that there is a difference between the MG gate and the general MG gates.-- ReyHahn ( talk) 15:41, 14 September 2022 (UTC)
Global phase is weird. I am starting to think that maybe I have been wrong about it even existing, doubting myself. But, in the books they kindof say that it does exist. For example, by saying that gates belong to U(2), and not SU(2). They also reference it by including it in factorizations.. But, however, IBM says that the Hamiltonian for it is useless ( link).
It has to exist, otherwise single-qubit gates would not belong to U(2), but SU(2). And intuitively (although I have not tested this), if one inverts the global phase early in the Grover's algorithm, then that would cause the algorithm amplify (with Grover's diffusion operator) all the wrong values, instead of the correct value(s) - essentially inverting the search query.
Why are people suggesting global phase does not exist?? Is it because it does not matter at all in normal quantum physics? · · · Omnissiahs hierophant ( talk) 16:10, 20 January 2023 (UTC)
I am pretty lay when it comes to the math behind quantum mechanics. I think a lot of people may have an interest in stuff like this. However, in just a few paragraphs the article jumps into things that only physics grads are going to understand. It would be nice if there was some more general and less intimidating information about how this works and its applications. The kinds of info a lay person could understand. As I understand it this page should really just describe what a Q logic gate is and how they can be applied. There should be another page with types of gates and the more complex descriptions of the mathematical formulas. I imagine that your average person reads of few lines on this page and gives up right away. Since this is an encyclopedia, it should contain the simplest way to understand how things work alongside the complex information. Thanks 162.246.112.154 ( talk) 19:51, 21 April 2024 (UTC)
Cite error: There are <ref group=lower-alpha>
tags or {{efn}}
templates on this page, but the references will not show without a {{reflist|group=lower-alpha}}
template or {{notelist}}
template (see the
help page).