I recently asked a question that was originally put "on-hold" (you can look at the question here: https://physics.stackexchange.com/q/245079/).

Now, I’ve read the homework policies several times, in an attempt to edit my problem so that it is more in concurrence with the site’s policy. I’ve edited the question already twice. I don’t understand why the question has not been reopened, since my purpose is to understand how to manipulate an operator when dealing with a higher spin system in general, not specifically for the case of my posted problem, which I’ve been working on for awhile now.

So my question is: what can be done to get this re-opened? Should I simply delete the post and then create a duplicate? I want to respect the site’s policies, and I understand that the Moderators don’t want to be haggled with homework questions, but at the same time... I’d like to get some clarification on the concept I stated above. Thanks in advance for the response!

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    $\begingroup$ Glad that you aired your query here in Meta rather than doing some menaces like few newbies. $\endgroup$
    – user36790
    Commented Apr 2, 2016 at 9:22
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    $\begingroup$ One thing that isn't made clear anywhere and hurts you here is that the automated submission of edited, closed questions for review only occurs on the first edit. If it takes you several tries to get to a good form then the review may already have gone against you before you're finished. That appears to have been the case this time. $\endgroup$ Commented Apr 2, 2016 at 14:52
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    $\begingroup$ I think this problem must be quite common. The reasons given for closing a question or putting it OnHold are very general and sometimes mystifying. They do not indicate specifically what needs to be done (both in terms of editing and asking for a review) to get the question re-opened. $\endgroup$ Commented Jun 7, 2016 at 0:08

2 Answers 2


I think the question is now perfectly acceptable, and I personally would vote to reopen it.

That being said, it's not very good for the community moderation model if I go around closing and opening things willy-nilly. Your question was reviewed twice since you edited it (first review, second review, and all four reviewers thought it was still inappropriate for the site. We should find out why. Hopefully at least one of them stops by to provide an answer (and I'll see if I can bug them about it).

Should I simply delete the post and then create a duplicate?

No, don't do that. Deleting and reposting questions is against our rules (of course as a new member, you probably wouldn't have known). If further edits are required, you can just keep editing the same question. Just try to batch up your edits so that you make all the changes required at once, and that you don't wind up editing the post too many times.

There are a few edits you could make to your question that would vastly improve it, and even though these shouldn't be the cause for it to stay on hold, given human nature, these might help the question's chances:

  • Don't post a screenshot of text from a book. Instead, retype the relevant parts of the text, making sure to use a quote block to indicate what you have copied from the book. (Make sure to acknowledge the source, too.)
  • Improve the math formatting by using the operator macros \sin and \cos, and writing kets as \lvert jm\rangle instead of |jm>.
  • Perhaps most important, give your question a better title. Even though the decision to put a question on hold should be based on the body, not the title, whatever title you do choose is your question's first impression to readers and it can influence their judgement of the body.

    In your case, "SU(2) Rotation Matrices Problem from Halzen and Martin" says nothing about what you're actually asking. Besides, the key word in the title is "Problem", which suggests that you want the solution to the problem from the book, even though that's not what you're actually asking in the body. A better title would highlight the conceptual issue you're actually asking about. Based on your wording in the body, you could go with something like "How can one obtain the eigenvalues of a rotated higher spin system?", or if you want it shorter, "Eigenvalues of a rotated higher spin system". (Titles don't have to be questions, though in my experience it's often easier to write a good title if you make it a question.)

  • $\begingroup$ Yeah that's good point; the original question wording does leave a bit to be desired; ok, I'll just delete the original post. $\endgroup$ Commented Apr 2, 2016 at 16:14
  • $\begingroup$ @MattSteinberg That's up to you, but certainly don't feel obligated to delete the post. In fact we usually recommend against deletion, since your question may still add value to the site. $\endgroup$
    – David Z
    Commented Apr 2, 2016 at 16:16
  • $\begingroup$ Well I meant to say, that I'll delete and think about how I can word the post better. But thanks for the recommendation. $\endgroup$ Commented Apr 2, 2016 at 16:19
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    $\begingroup$ @MattSteinberg Ahh, well if you're going to delete it temporarily while you work out how to edit it, that's fine. My point was just that we prefer not to have good content disappear from the site permanently, and I think your question is good content, or at least is pretty close to it. $\endgroup$
    – David Z
    Commented Apr 2, 2016 at 16:25
  • $\begingroup$ Thank you! Ok, I'll see if I can rehash it and send it out again soon. $\endgroup$ Commented Apr 2, 2016 at 16:26
  • $\begingroup$ @DavidZ : Your suggestions for improving the appearance of the question seem trifling to me. Surely the question should be judged by its content, not its appearance. And if, as you agree, the content was ok, why was it still On Hold? $\endgroup$ Commented Jun 7, 2016 at 0:00
  • $\begingroup$ @sammygerbil Appearance matters. It is possible for a question with perfectly good content to be ruined by terrible formatting, spelling, grammar, etc. In particular, I consider the issues I mentioned to be relatively major formatting problems. Also: I've already explained in the answer why I didn't unilaterally reopen the question. $\endgroup$
    – David Z
    Commented Jun 7, 2016 at 0:31

A quick note on this: Matt posted his question in a series of edits that took about half an hour to reach the final form. I saw the question at an intermediate stage and it looked very like homework hence the close vote. In it's current form the key bit of the question is:

How can one obtain the eigenvalues of a higher spin system than ${1/2}$ when operated on by a rotation matrix operator, like $e^{-i{\theta}J_{i}}$, where $J_{i}$ is the rotation group around any of the 1, 2, or 3rd axes?

And this seems to me to be a reasonable question. However the lengthy preamble and in particular the images that make up the first part of the question do make it look like an attempt to get us to do a problem, and I suspect many site members would have lost the will to live before they reach the actual question.

Meta posts like this one have a high success rate in getting questions reopened, but that doesn't necessarily mean the question will attract good answers. I would be inclined to rethink what exactly is being asked and post a new question that is better focused.

  • $\begingroup$ Ok so you're probably right; I think I'll just delete the original question, and re-write it using different formatting and different wording. Thanks for the input! $\endgroup$ Commented Apr 2, 2016 at 16:13

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