What exactly does "graduate level and above" mean, and how is it judged?

Question

I'm thinking of re-asking some of my old Physics Stack Exchange questions on this site. From my point of view this would be great, as they're definitely above the level of most of the questions on Physics.SE, and they'd benefit greatly from being viewed by people with a greater level of expertise.

However, my problem is that although I'm an expert in some areas of physics, I'm not a physics graduate{1} and my questions are in areas of physics where I haven't taken graduate-level courses, or indeed any courses at all besides browsing online resources and reading a paper or two. In general it seems to be a common feature of Q&A sites that people tend to answer questions in their area of expertise, but ask questions on their hobby subjects.

So I guess my first question is, does "graduate level" mean "asked by someone who has taken a graduate course (or has equivalent experience)", or something weaker like "requires someone with grad-level expertise to answer" or "likely to be of interest to graduates in the sub-field"? Or even "asked by someone with grad-level expertise in some area of physics, but not necessarily the one they're asking about", which is what would describe me in most cases.

Regardless of the answer to this, my second question is, who judges the level of the questions? This seems like quite a tricky issue, and I'm sure you've thought about it quite a bit, so I'd like to know your thoughts on it.

Below are some examples of my questions on Physics.SE. I've deliberately chosen ones where I'm not sure whether "graduate-level" would be an appropriate label. (The last one is an exception - I do have grad level experience in QM, but I'm not sure whether the question would be considered "too philosophical". I rather hope it wouldn't, but I don't know how the community here feels.) I would be iterested to know whether the community/moderators feel that these questions are of a high enough "level" to be appropriate on this site.

http://physics.stackexchange.com/questions/103997/are-the-hamiltonian-and-lagrangian-always-convex-functions

http://physics.stackexchange.com/questions/31534/phase-space-volume-and-relativity

http://physics.stackexchange.com/questions/22942/intensity-of-hawking-radiation-for-different-observers-relative-to-a-black-hole

http://physics.stackexchange.com/questions/22498/from-where-in-space-time-does-hawking-radiation-originate

http://physics.stackexchange.com/questions/23753/information-conservation-during-quantum-measurement

_{{1} my PhD is in complex systems - I used a lot of stat mech and can certainly answer graduate-level questions on that topic, but I wasn't in a physics department}

Comments

See this: http://www.physicsoverflow.org/13330/reputation-for-research-level-questions . I think we should have a "difficulty" or "researchiness" score separate from the usual vote, to allow people to post questions without inhibition, even if they are low-level, just mark the ones that are difficult by voting. This extension is required for reviews anyway, so the code will get written (possibly by me, hopefully, but I haven't done it yet, and I don't want to make any promises I can't keep)

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For what it's worth, your questions are good.

Answer 1

If I am not wrong, "Graduate-level" means that either

• the topic of the question comes under the syllabus of a graduate program, or 
• is "research-level", i.e. a topic of cutting-edge research in physics.    

By the way, regarding re-asking, instead of re-asking all your questions (I'm not even sure if that is legal as per SE's CC-by-SA license), I will import your posts soon.  

Comments

Ok, but do those criteria apply to the example questions I posted? As a non-physics graduate it's very difficult for me to judge this. I would guess that most of them are not on graduate syllabi, otherwise I would most likely have been able to find the answers by googing. In a sense at least some are research-level, in that if I figure out the answer and it turns out to be novel then I might try to publish it; but again it's very difficult for me to judge whether a proper physicist would consider it "cutting edge".

A vague, ambiguous or subjective definition will discourage participation. I'm happy to only ask questions of the appropriate level, but if people don't have a way to judge that then they will worry that my questions might be closed, making them less likely to ask them here in the first place. (The same thing happens over at Physics.SE with its policy of "every question has to be about physics, as defined by the moderators' whims.") I don't have a good answer to this - it surely will be necessary to close or somehow filter low-level questions as the site gets more popular, and the call has to be made somehow - but I do think it's something worth discussing at the early stages.
 

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@Nathaniel If you ask me, all of them seem rather on-topic to me. I am sure about the last three, first should be on-topic most likely, but I am not completely sure about the second (though I think it is a fair question).  

Answer 2

I like to complete what Dimension10 said and how I (and probably others) saw it up to know:

The structure of PhysicsOverflow

PhysicsOverflow has (or will have) two different sections. The Reviews section will naturally be exclusively research-level, as its purpose is to peer review and discuss research papers in a faster, public, and more transparent frank and honest way.

The Q&A part, is intended to have a similar functionality as  MathOverflow and to take the role of a reborn Theoretical Physics SE with a slightly broadened scope (including experimental physics) and lowered bar to ask. So as concepted so far, the Q&A part is intended to contain graduate-level and research-level questions.

My personal thoughts about this (which are open to vigorous disputation)

• In the Q&A section, nontrivial enough (including technical) questions as they come up from reading advanced graduat-level text books, following advanced courses, and reading research-papers, should be allowed too.
• I personally do not think that the Q&A section needs a more sophisticated voting scheme than Theoretical Physics had and MathOverflow has. As Dimension10 says somewhere, I think too, that things will play out naturally such that higher rather research-level questions (and answers) will obtain more positive votes than lower-level but still on-topic posts
• Just yesterday in the course of an email discussion, Piotr Migdal who was a Theoretical Physics moderator gave me a link to a discussion about restarting Theoretical Physics somewhere. There people came to the same conclusion as we, that it is better to broaden the scope to experimental physics  and lower the bar to ask to graduate-level. So if bad (really too trival, wrong, incorrect) things are voted down, commented on properly, and closed/deleted if needed, I personally see no harm in have graduate-level and research-level questions in the Q&A section.

Comments

Thanks, that's useful information. But the question isn't so much "should we have graduate-level questions", it's "(1) what criteria are used to judge whether a question is of sufficient level, and (2) by whom are these criteria applied?"

A precise answer to (1) is necessary in order for me to participate. I learned virtually all my physics after graduating from other subjects, so I have very little idea what a physics graduate does or does not know. If you leave it vague you risk all of the questions being essentially advanced-level homework, because those are the only types of question where anyone can be sure that it's definitely graduate level.

To (2), I guess the de-facto answer will be "the moderators", at least to begin with. But what happens in the case of a difference in opinion? Do the moderators reign supreme, or can the community overrule them? (And if so, under what circumstances, and how?) From our shared experience, it seems a good idea to form a policy on this early on. In any case, disagreements will be much less likely if the answer to (1) is made precise.

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Hi Nathaniel,

I pesonally prefer determining rather dynamically what questions the community likes and appreciated and formulating rather open guidelines than rigorous detailled policies which only can be adapted by overcoming huge bureaucratic obstacles if the formulation and enforcement is not what the community wants after all. I think this is how they handle things on Math SE, MathOverflow, and on Theoretical Physics it has been similar.

As I see it post should only be unilaterally closed/deleted by moderators, experts, or admins of they are obviously bad and/or off topic.

In general, closing/reopening/(un)deleting should rather be community driven, by making use of the review queue imitations accessiblie via the Moderate link via the top menu bar for anybody who has >500 points.

I personally think that as long as the questions are interesting enough to the community, people who are for example self studying topics they have not taken graduate level courses about, should be able to ask questions too.

So I think you (and others) can just ask questions and see what happens.

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@Nathaniel 

1. For (1), It is hard to make an objective differentiation between graduate-level and non-graduate-level but for example, advanced GR and Relativistic QM are the bottom markers of the graduate-level spectrum in TP, EP, and GP. In Phenomenology, really most of what you hear as "Phenomenology" is graduate-level, in fact research-level. In Mathematics, the mathematics should just pertain clearly to graduate-level Physics. I can't speak.  
2. For (2), it will mostly be the community, and the community's decision should almost always overrule a moderator's decision (i.e. the moderators are required to execute the will of the community, even if it clashes with their own opinions. But the community may not overrule one thing; the principle of community moderation. For example, they may not vote to censor a topic, or censor frankness, etc.              

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Thanks both of you, this is useful to know. I totally agree that things should be dynamic and community-driven - I guess on reflection I take back what I said about precise definitions.

But it is good to be clear about procedures, and it's nice to have this stuff on the table. I was a little worried that questions might be closed on the basis of being not grad-level enough, leading to disagreements, but your comments have put that to rest, at least for now. 

@dimension10, the definitions you're giving of graduate level aren't so helpful to a non-physics graduate I'm afraid. Since I didn't study physics I have no idea what topics "Relativistic QM" encompasses, or whether it's taught before or after density matrices and path integrals, for example. But if we're going with a more dynamical, community-led way of determining on-topicness then that doesn't matter so much.

Personally, my opinion is that everything should be considered on topic unless questions of that type have actually cased a specific problem in the past (here or elsewhere). From what you've said I think both of your opinions are broadly in line with that, which makes me hopeful abou this site.