Timeline for How can a disentangled state be contextual?
Current License: CC BY-SA 4.0
22 events
| when toggle format | what | by | license | comment | |
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| S Jul 3, 2021 at 5:44 | history | bounty ended | lurscher | ||
| S Jul 3, 2021 at 5:44 | history | notice removed | lurscher | ||
| Jun 29, 2021 at 15:32 | comment | added | D. Halsey | "... the essence of quantumness, i.e., entanglement. " Entanglement may be what interests you the most about QM, but it doesn't even rate a mention in the index of some QM texts. (Modern Quantum Mechanics, by Sakurai & Napolitano) | |
| Jun 29, 2021 at 12:59 | answer | added | Chiral Anomaly | timeline score: 3 | |
| Jun 27, 2021 at 19:46 | comment | added | Tfovid | @ChiralAnomaly Yes, that's my question. | |
| Jun 27, 2021 at 16:19 | answer | added | Valter Moretti | timeline score: 3 | |
| Jun 27, 2021 at 15:11 | comment | added | Chiral Anomaly | Trying to cut through the jargon to understand the question... Are you asking for more insight about how the Peres-Mermin square manages to show that hidden variables must be contextual (i.e., chosen differently based on what else is being measured) even when they're only required to reproduce quantum theory's predictions for states that are initially unentangled? | |
| Jun 27, 2021 at 14:16 | comment | added | ACuriousMind♦ | You just edited the title, which just makes this question more confusing, since now the title asks about contextuality but the body talks about realism. | |
| S Jun 27, 2021 at 14:12 | history | bounty started | lurscher | ||
| S Jun 27, 2021 at 14:12 | history | notice added | lurscher | Draw attention | |
| Jun 27, 2021 at 13:13 | history | edited | Tfovid | CC BY-SA 4.0 |
More accurate title
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| Jun 27, 2021 at 12:59 | comment | added | glS | @Tfovid I think yours is a legitimate question, but the current title is simply not doing it justice, as it makes it seem like you are asking something rather different. Local realism is not the same thing as contextuality, and it is often discussed/treated in different contexts (well, you know what I mean). I'd suggest a title more on the lines of "How can a disentangled state be contextual?" or such. It also seems to me that, whereas nonlocality/entanglement are properties of a behaviour/state, contextuality is a property of a physical theory, not of a specific QM state | |
| Jun 27, 2021 at 12:26 | comment | added | Tfovid | As for my title, I just took nonlocality as a special case of contextuality whenever the two-mode system spans space-like separations. | |
| Jun 27, 2021 at 12:26 | comment | added | Tfovid | My emphasis is indeed on contextuality. It seems surprising that say, thermal, disentangled states can lead to a non-classical phenomenon such as contextuality when they don't have the essence of quantumness, i.e., entanglement. | |
| Jun 26, 2021 at 14:06 | comment | added | glS | my previous question was mostly about the title of the question itself btw. I can see from the comments that you are mostly interested about contextuality, but that's not what the question in the title is asking. The answer to the question in the title is that yes, you can have separable (nonpure) states violating some Bell inequality (i.e. local realism). | |
| Jun 26, 2021 at 14:03 | comment | added | glS | @Tfovid I suppose you mean because the contextuality result explained via the Peres-Mermin square works regardless of the state one is computing the expectation values on? Yes I guess you could have it for pure disentangled (i.e. product) states as well. But why do you say it would be problematic? To me it simply indicates that contextuality is a property that is rather different than nonlocality etc | |
| Oct 25, 2020 at 15:00 | history | tweeted | twitter.com/StackPhysics/status/1320379609259671554 | ||
| Oct 25, 2020 at 9:25 | comment | added | Tfovid | @glS Mixed states can violate local realism since they can still contain some quantum coherence, albeit "diluted". My concern was instead that some pure, disentangled states can exhibit contextuality (e.g., Peres-Mermin square). Wouldn't that mean that, in turn, they violate local realism? If so, wouldn't that be very problematic? | |
| Oct 24, 2020 at 16:55 | comment | added | glS | I do not understand the question. You state correctly that non-pure states can violate local realism while not being entangled (note that if you stick to pure states it's not possible, as per Wiseman et al. arxiv.org/abs/quant-ph/0612147) | |
| Oct 24, 2020 at 16:47 | history | edited | glS |
edited tags
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| Oct 16, 2020 at 19:49 | comment | added | user65081 | Why is realism violated? non-local hidden variables are not ruled out | |
| Oct 16, 2020 at 15:01 | history | asked | Tfovid | CC BY-SA 4.0 |