Reopen “Can superstring theories predict our 4 dimensions?”

Question

This question of mine has been marked as duplicate. I tried to argue my case in the text of my question but it seems this forum is more appropriate. My apologies if this is not so.

It is a definite duplicate of Q10075 which has rather low quality answers: no, superstrings can't predict only 4 dimensions are not compactified. My question was also marked as a duplicate of Q10651. It did not seem obvious at first as superstrings were not discussed at all there but I shall thank the moderator for the pointer because one of the answer, A10723, cites a paper "Relaxing to Three Dimensions by Karsh and Randall which, although it is far too advanced for my current understanding of physics, seems to answer my question with a "yes". Here is the abstract:

We propose a new selection principle for distinguishing among possible vacua that we call the “relaxation principle.” The idea is that the universe will naturally select among possible vacua through its cosmological evolution, and the configuration with the biggest filling fraction is the likeliest. We apply this idea to the question of the number of dimensions of space. We show that under conventional (but higher-dimensional) FRW evolution, a universe filled with equal numbers of branes and antibranes will naturally come to be dominated by 3-branes and 7-branes. We show why this might explain the number of dimensions that are experienced in our visible universe.

From the page of the paper, I clicked on "cited by" and there seems to be a handful of papers arguing the same point, but again I am at the level of matching buzzwords! As for the answer itself which quotes this paper, it is again of low quality as it adds no value at all to the paper.

To summarise, we are in a situation where existing answers seem either wrong, or are useless to me, and by extension to anybody who is not a postgraduate-level physicist. May I enquire what could be done?

Answer 1

To summarise, we are in a situation where existing answers seem either wrong, or are useless to me, and by extension to anybody who is not a postgraduate-level physicist. May I enquire what could be done?

If you're having trouble understanding an existing answer, you can ask a followup question about that answer. For example, if you wanted more information about a specific aspect of the answer - say, the assumptions required to get the Karch & Randall argument to work - you might ask something like

This other answer references a paper by Karch & Randall in which they determine that 3-dimensional objects are likely to dominate interactions among different higher-dimensional objects. It says they had to make some unrealistic assumptions to get this to work; what are those assumptions? I've tried [list your other efforts to understand] but I can't make sense of it.

Obviously, adjust this to suit your writing style and the actual aspect of the answer you want to know about.

Another thing you can do is try to bring more attention to the original question in the hope that someone will post an answer which is more useful to you. You can do this by setting a bounty, by asking for help in chat, or by sharing the link on- or off-site. (In practice, posting a followup question, or a meta post, if one is warranted, are both effective ways to bring attention to a question.)

What you should not do is post another question asking the same thing as the original question you're looking at in the hope of getting answers that are more useful to you. That's just a duplicate, and will be marked as such (if somebody notices). If you think the answers to the original are bad, or useless to you, that's not an argument against the question not being a duplicate.

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Note that when your question is marked as a duplicate, sometimes you can edit it to make it not a duplicate, by explaining what you're asking that the original question isn't. But any argument that a question isn't a duplicate of another must be based on the questions only, not the answers. Answers do not factor into whether two questions are considered duplicates.