I asked the question Confusion over QM Free Particle Propagator - Shankar 5.1 last night and it was closed as a duplicate earlier today, because it is similar to the question Free particle Schrodinger equation: propagator.

However, the (apparently automatically generated) closure note states the following:

If this question doesn’t resolve your question, ask a new one.

As far as I can see, this is precisely what I did. The previous question and its answer were not sufficient to resolve the question for me, so I asked a new one. I tried to make it clear in my new question why the previous one and its answer didn't help and what aspects of an answer I thought would help to resolve my issue.

So, I have to say, I am confused as to what the site policy is regarding asking similar questions to previous ones and what I should do in this situation, where an answer to an existing question does not help. From my point of view, I did precisely what the closure note says and my question was closed anyway. If that advice is no longer consistent with site policy, perhaps the note should be updated to clarify? Tbh, that note seems to be rather contradictory, since it seems to be recommending to someone to do what got their question closed in the first place.

I'm sorry, but for me the existing answer to that question simply does not provide a good enough explanation.


1 Answer 1


TL;DR It looks like you put the duplicate stuff up front as the title and as the main part of the question, and you hid the new and important stuff at the bottom of a "note". Therefore, it makes sense that the question was closed, as it really does seem to mainly be a duplicate. This can easily be fixed by focusing on the right things though.

Full response:

It is a tricky situation. but I think the site policy was applied correctly here. As it stands, the title and main parts of your question not in your "note" are answered in the duplicate. The policy is still fine, and the advice in the banner is still fine.

However, you have also included confusions you have with the duplicate, and you have questions based on that. Therefore, I think you are entitled to have a question about it that can be answered.

Questions that are edited can be reopened if other users vote for it to be open, but since you already have an answer on your question, I don't think the best move is to heavily edit the existing question. I would suggest making a new, better question. However, I would make sure to focus on the right things.

1) Take out most of the first part of your question, as it really does make it look like a duplicate. Only include what is necessary to make your actual question make sense.

2) This part

Has Shankar glossed over this, in his earlier description of the propagator? If so, why would he do that? Does he address this point anywhere else in his book (as it seems fairly important)?

is a little too opinion based, and is more about the text book and less about the physics. I don't think it is needed in your question.

3) This part

Can anyone explain more clearly why this Density of States is required and where it comes from? I thought the degeneracy of H was being accounted for by summing over the +/- values of p - why would an extra term be required?

is the heart of your question that makes it distinct from the duplicate. So then why did you hide it in the middle of a "note" section, and why is your title not about this instead? Make this the focus. Frame your question around this. Then you will actually have a new question (assuming that this also hasn't been asked about before).

  • 2
    $\begingroup$ Thanks for your advice - you make some good points. I'll try what you suggest and make a new question that focuses in on the points I still don't understand and that aren't covered by that previous question/answer. $\endgroup$
    – Time4Tea
    Commented Jan 28, 2020 at 16:06
  • 2
    $\begingroup$ FYI: New question asked here $\endgroup$
    – Time4Tea
    Commented Jan 28, 2020 at 16:52

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .