Timeline for How are elementary quantum gates realised?
Current License: CC BY-SA 4.0
16 events
| when toggle format | what | by | license | comment | |
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| Sep 19, 2023 at 0:16 | answer | added | Mark Spinelli | timeline score: 1 | |
| Sep 18, 2023 at 15:11 | history | edited | glS♦ | CC BY-SA 4.0 |
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| Dec 23, 2018 at 14:17 | history | edited | Sanchayan Dutta |
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| Mar 24, 2018 at 13:04 | history | edited | glS♦ | CC BY-SA 3.0 |
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| Mar 23, 2018 at 22:32 | comment | added | DanielSank | Chapter 1 and especially appendix D of my PhD thesis explain how abstract logic comes from the dynamics of superconducting qubits. | |
| Mar 23, 2018 at 18:01 | comment | added | Mithrandir24601♦ | It's going to vary based on the 'implementation' of the system (i.e transmons will be different to linear optics, different to trapped ions etc.), so would you be able to narrow this down a bit further? | |
| Mar 23, 2018 at 10:19 | history | edited | glS♦ | CC BY-SA 3.0 |
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| Mar 23, 2018 at 6:23 | answer | added | GroundhogState | timeline score: 8 | |
| Mar 22, 2018 at 13:00 | comment | added | glS♦ | No, I'm asking about the methodologies used today to implement gates, which are more or less the ones I mentioned above. This is different than asking about how gates are decomposed in terms of easier (in a given architecture) gates, because that is just one way to do this. I edited the question trying to make this point clearer. Here is an example of a paper using one such technique to implement a Toffoli: arxiv.org/abs/1501.04676, which might enlighten as to the kind of answer this question may have | |
| Mar 22, 2018 at 12:54 | history | edited | glS♦ | CC BY-SA 3.0 |
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| Mar 22, 2018 at 12:50 | comment | added | Niel de Beaudrap | So, you want to know how to decompose e.g. a Toffoli gate, but in some architecture, with an account of how the whole architecture works? Analogous to a description of how one realises NAND in terms of semiconductor physics, except for the more immature technological setting of quantum computation, where we are pretty sure that we have not yet completely solved the problem of scaling in any of our candidate technologies? I'm not sure your question will have an answer yet; and once it does have an answer, it will represent at least half of a semester course in engineering. | |
| Mar 22, 2018 at 12:35 | comment | added | glS♦ | @NieldeBeaudrap the kind of answer I expect is something highlighting that the way more complex gates (say, Toffoli gates) are implemented is through 1) gate decomposition using sets of gates which are "simple" in a given architecture (which brings the highly nontrivial problem of quantum compilation), 2) quantum control techniques, 3) using ancillary degrees of freedom, 4) implementing the gate as an effective dynamics in a larger Hilbert space, 5) possibly other methods | |
| Mar 22, 2018 at 12:32 | comment | added | Niel de Beaudrap | I'm making a rhetorical point: that the same argument could be directed at classical computation, but we allow ourselves the luxury of abstraction there because we know that the operations are realisable in principle, by a suitable application of manufacture and control. The only question is what level of 'principle' would satisfy you. Think about the analogy to the classical case: if you didn't know about consumer electronics, what level of detail would you hope for to be satisfied that NAND is physically realisable, rather than just as an intellectual abstraction for reasoning? | |
| Mar 22, 2018 at 12:15 | comment | added | glS♦ | @NieldeBeaudrap I'm not sure whether you are rephrasing the question or asking something. Anyway, the dynamic generating a gate is important as soon as you need to actually implement the gate, it is just not directly dealt with when writing algorithms (though it is still considered, which is why most algorithms are expressed in terms of gates whose decomposition in terms of elementary gates are manageable). You don't need to worry about this in the classical case because we know very well how to make complex operations out of easy ones, but this is not the case with current quantum devices | |
| Mar 22, 2018 at 12:12 | comment | added | Niel de Beaudrap | When expressing classical computations in terms of logical operations, one makes use of gates. In some sense, these are essentially black boxes, whose inner workings are not often dealt with while studying classical algorithms. However, that is not how nature works: states evolve in a continuous fashion describable by differential equations. When talking about classical algorithms, one neglects the dynamic realising said evolution, which is how the gates are actually realised in physical systems. But the dynamic generating a gate is unimportant, so long as the gate can in fact be realised. | |
| Mar 22, 2018 at 11:54 | history | asked | glS♦ | CC BY-SA 3.0 |