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Help pick the subdomain for the site: discuss.area51.stackexchange.com/questions/2814/… – Joe Fitzsimons Sep 7 '11 at 6:01

61 Example Questions (7 closed)

active newest votes

up vote 20 down vote

added by Anthony Leverrier Nov 13 '10 at 19:50

up vote 20 down vote

added by Marcin Kotowski, edited by WikiSpeedia hang-around Nov 16 '10 at 10:56

Great example. There is a lot of confusion about the subject. Especially since ergodicity is absolutely unnecessary to the foundations of stat mech. – Raskolnikov Nov 16 '10 at 11:06

@Raskolnikov: I quite agree with you except that I wouldn't go as far as to say absolutely. There are lots of interesting connections between ergodic theory and statistical mechanics. But I guess absolutely unnecessary is a great deal better than absolutely necessary which is what is still being taught in lots of physics classes. – Marek Nov 16 '10 at 11:50

up vote 19 down vote

added by Joe Fitzsimons Nov 13 '10 at 18:35

up vote 19 down vote

added by Joe Fitzsimons Nov 13 '10 at 18:38

up vote 19 down vote

added by Sarah Kavassalis Nov 14 '10 at 19:07

Great to see you here Sarah, and great question. – Joe Fitzsimons Nov 14 '10 at 19:09

up vote 13 down vote

added by Piotr Migdal, edited by WikiSpeedia hang-around Nov 16 '10 at 10:58

I am not sure I understand the question properly, so just to clarify: by singlet states do you mean states with spin zero and by Majorana-like do you mean that particle is its own antiparticle? Then sure, this corresponds to real scalar field whereas complex scalar field gives you "Dirac singlet states" (which can, in principle, carry a charge). But if you meant it in this way then I think it's way too basic. However, opinions can surely vary on what is considered basic. – Marek Nov 18 '10 at 11:29

I think the question refers to the Majorana representation of symmetric states, ie states of n qudits invariant under a permutation of the qudits. See for instance arxiv.org/abs/1001.0343 – Anthony Leverrier Nov 23 '10 at 23:17

up vote 12 down vote

added by Dave Bacon Nov 14 '10 at 19:59

up vote 6 down vote

added by Piotr Migdal Nov 14 '10 at 17:04

up vote 6 down vote

added by Frédéric Grosshans, edited by WikiSpeedia hang-around Nov 16 '10 at 10:53

	The example I had in mind writing this question: trying to deduce quantum mechanics from a set of information theory related axioms. – Frédéric Grosshans Nov 15 '10 at 10:05
	Is the purpose of this site for people to write mini-reviews about their field? I would prefer to see focused questions. – j.c. Nov 18 '10 at 19:42

up vote 6 down vote

added by Dave Bacon Nov 14 '10 at 20:21

I would actually put this on the current physics site, since I'm pretty sure the answer is "yes," and it's not hard to explain why. It strikes me as the kind of thing researchers would consider fairly obvious. – David Z Nov 16 '10 at 4:49

up vote 6 down vote

added by Marek Nov 14 '10 at 21:38

up vote 5 down vote

added by Blake Stacey Nov 14 '10 at 20:11

	If the question stood "Which models..." I'd have liked it. This way it looks a bit too experimental. But I am not sure. – Marek Nov 14 '10 at 21:34
	I see your point; on the other hand, a theorist might be approaching the subject from, e.g., highly mathematical papers on conformal field theory and be looking for something a little more physically grounded. – Blake Stacey Nov 15 '10 at 18:58
	@Blake: I guess you are right. As pointed out elsewhere on this site: asking for physical evidence for a given model is definitely on-topic. Only asking for a concrete realization of some experiment (or problems thereof) is probably off-topic. – Marek Nov 16 '10 at 11:55
	I don't see how probing how relevant theories are to real materials is off topic..? Or perhaps my idea of physical theory doesn't quite coincide with everyone's. – j.c. Nov 18 '10 at 19:41

up vote 5 down vote

added by Blake Stacey Nov 15 '10 at 18:59

Maybe not a research-level question, but it seems plausible that a non-GR-specialist would ask something like it. – Blake Stacey Nov 15 '10 at 19:03

up vote 5 down vote

added by Frédéric Grosshans Nov 18 '10 at 17:29

Lifted from ABO to see if experimental question would be welcome on this site. As said by @Joe Fitzsimons, it's up to the community to decide, and if "if experimental questions become accepted as good on-topic examples we could change the title to reflect the broadened scope. " – Frédéric Grosshans Nov 18 '10 at 17:32

@Frédéric: I am a pure theoretician but you got me hooked with the question. Let's see what others think. – Marek Nov 18 '10 at 19:35

@Marek : The credit should go to @Matthias Rosenkranz : He proposed this question on AMO – Frédéric Grosshans Nov 19 '10 at 15:05

up vote 4 down vote

added by Marek Nov 14 '10 at 21:13

up vote 3 down vote

added by Chris Granade Nov 14 '10 at 19:13

up vote 3 down vote

added by Marek Nov 14 '10 at 21:21

up vote 3 down vote

added by user23893 Nov 14 '10 at 22:48

up vote 3 down vote

added by Jim Harrington Nov 15 '10 at 6:59

up vote 2 down vote

added by Marek Nov 14 '10 at 21:17

up vote 2 down vote

added by seandbarrett Nov 15 '10 at 13:14

up vote 2 down vote

added by Piotr Migdal Nov 15 '10 at 16:24

	Question posted deliberately to see if research-level questions not restricted to theory are welcome. Personally, I care much to have it as an example on-topic question in SE I would like to contribute. – Piotr Migdal Nov 15 '10 at 16:40
	I see no reason for granular media physics to be excluded from theoretical physics. – Frédéric Grosshans Nov 15 '10 at 23:05
	I think no-one is going to question granular media. On contrary, some may not want to have here experiment. – Piotr Migdal Nov 18 '10 at 17:32

up vote 2 down vote

added by John Joseph M. Carrasco Nov 16 '10 at 7:28

up vote 1 down vote

added by Chris Granade Nov 14 '10 at 19:15

up vote 1 down vote

added by Dave Bacon Nov 14 '10 at 20:25

closed as off topic by Marcin Kotowski, Anthony Leverrier, Marek, rz_, Daniel Nov 14 '10 at 22:48

This question does not relate to the topic of the proposal.
It was closed as part of an automated migration of off-topic to close votes on September 29, 2011.

As far as I understood (i.e. not much), Lisi's "Exceptionallay simple" theory has been first found interesting by some theoreticians. Then it has been found "too simple". Why flag it off-topic ? – Frédéric Grosshans Nov 17 '10 at 9:32

@Fréderic: I think it is by now a common knowledge in the theoretical community that this is just a crackpot theory. Physics.SE should be fine to answer this sort of questions (e.g. recently they answered something similar about the Heim theory). – Marek Nov 17 '10 at 16:28

@Marek : thanks for the clarification – Frédéric Grosshans Nov 18 '10 at 10:55

up vote 1 down vote

added by Marek Nov 15 '10 at 13:27

I think this is too basic; a very quick Google or arXiv search would yield the answer. – Sarah Kavassalis Nov 16 '10 at 3:28

@sk Oh I don't know about "the answer" ;-) -- although I agree that the question's possibly a little broad to headline as a "great" example . I could see the discussion spanning: gravity as double-copy of gauge theories via color-kinematic duality, or gravity from KLT relations, or AdS/CFT, or FRW/CFT, or even Andy's recent Kerr black hole stuff. I'd see the precise workings of any of those being worthy of current and active research-level discourse. Even the most-well studied correspondence AdS5/CFT is certainly not a closed subject. – John Joseph M. Carrasco Nov 16 '10 at 7:03

@Sarah: the same thing can be said about lot of other questions here. I am not sure whether you want to prohibit asking about anything that can be find on arXiv (which is basically everything there is). @sk: Yes, I realized the question might be too broad. Still, it's something that (say) a GR student with a little knowledge of gauge theories might be interested in (and your "answer" is fine). Maybe not a great example but to me it seems certainly nice and relevant question. – Marek Nov 16 '10 at 7:52

@John: I realized that your comment wasn't targeted at me. FYI though, I think you need at least three (consecutive?) letters for @ to work. – Marek Nov 16 '10 at 8:01

@John I completely agree with you. I probably should have said that I thought it was too basic/general of a question, as phrased (also, I'm not a fan of the "what are some papers on this" type questions, unless it's on a very precise topic, when those are pretty easy to find without stackexchange). The precise workings of any area of gauge-gravity duality are certainly worthy of discussion. – Sarah Kavassalis Nov 16 '10 at 15:04

up vote 1 down vote

added by Peadar Coyle Nov 18 '10 at 9:12

up vote 1 down vote

added by Daniel Nov 23 '10 at 22:38

up vote 0 down vote

added by Tsuyoshi Ito Nov 13 '10 at 21:46

closed as off topic by Matt Reece, Joe Fitzsimons, Marcin Kotowski, Wikis, Cedric H. Nov 14 '10 at 18:20

This question does not relate to the topic of the proposal.
It was closed as part of an automated migration of off-topic to close votes on September 29, 2011.

Copied from physics.stackexchange.com/questions/17/… to clarify the difference between the two proposals. (That is, this question is intended to be an off-topic example.) – Tsuyoshi Ito Nov 13 '10 at 21:47

Excellent. Thanks Tsuyoshi! – Joe Fitzsimons Nov 13 '10 at 22:22

IMHO it should stay in physics SE (while interesting, it is not research-level, as the answer is widely known). – Piotr Migdal Nov 14 '10 at 18:50

@Piotr: I think most people agree with you, which is why there are 9 votes for it as being a good example of what is off topic. – Joe Fitzsimons Nov 14 '10 at 19:07

up vote 0 down vote

added by Marcin Kotowski, edited by WikiSpeedia hang-around Nov 16 '10 at 10:54

With one remark: I would prefer to have questions about a certain thing, not asking for a review of a subject. – Piotr Migdal Nov 14 '10 at 19:27

You can easily rephrase the question as "How many MUBs can there exist in a given Hilbert space ?", then it's a question about a certain thing :) – Marcin Kotowski Nov 14 '10 at 19:30

What is the problem with a review ? – Frédéric Grosshans Nov 17 '10 at 14:21

up vote 0 down vote

added by Wikis Nov 14 '10 at 21:27

closed as off topic by Piotr Migdal, Jim Harrington, Georg Lind, Steve Flammia, Igor Ivanov Nov 15 '10 at 22:08

This question does not relate to the topic of the proposal.
It was closed as part of an automated migration of off-topic to close votes on September 29, 2011.

	Probably off-topic. – Wikis Nov 14 '10 at 21:29
	Added here: physics.stackexchange.com/questions/1203/… – Wikis Nov 22 '10 at 13:57

up vote 0 down vote

added by Tracy Hall Nov 15 '10 at 7:59

I would argue that this could actually go on the current Physics beta site, since the answer involves intro-level quantum field theory. – David Z Nov 16 '10 at 2:25

@David: I am not really sure I would call the answer intro-level (e.g. the level of my intro QFT course was certainly much much lower). Also, I don't think the majority of the community at the physics.SE would appreciate the details of the anomaly cancellation. The community of this site, on the other hand, might (at least the ones who don't yet know the answer). So I think it's a fine question for (say) grad student to ask, even though it's not strictly research level (although it might be reformulated to include SUSY and other stuff). – Marek Nov 17 '10 at 15:17

@Marek: okay, maybe not exactly intro-level. Intermediate, perhaps. Still, I think that any research-level physicist on this site would either already know about the anomaly cancellation, or wouldn't particularly care because it's irrelevant to their research area. Plus, questions like this, concerning the established foundations of physics at an advanced undergrad/early graduate level, are exactly what we're trying to encourage on the current physics SE site. – David Z Nov 17 '10 at 19:05

@David: I see, I wasn't aware of this. In that case I am afraid that some of my own proposed questions here would be better suited to physics.SE. Although it has to be said that they got quite a few votes already (possibly because people made the same assumption as I did that graduate-level questions are still fine for TP.SE). – Marek Nov 18 '10 at 0:28

@Marek: Your other proposed questions actually do seem more geared toward current research than this one (although there would be no harm in asking them on physics.SE if you want). The standard model is fairly well-established physics. Anyway, I think this question is right about where I'd like to see the boundary set between the two sites, so it could fit in on either one. But physics.SE needs high-level questions to help keep the pop-sci stuff from taking over, whereas that's not at all a concern for TP.SE. So if I had to pick only one place for this question, it'd be physics.SE. – David Z Nov 19 '10 at 22:40

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up vote 0 down vote

added by John Joseph M. Carrasco Nov 16 '10 at 7:23