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I Reading a Paper on the Cosmological Constant Problem

  1. Jun 20, 2016 #1
    My professor wants to give me (and another kid) a problem in quantum cosmology. To that end, he asked me to read through his recent paper that appeared in the Physical Review Letters. He said that I should be able to go through it since all the paper employs is (quantum) scalar field theory, which you have been doing as part of your studying QFT in the summer.

    I, however, upon looking at the paper am clearly stmped as I can't make a word out of it. To me, it seems heavy on GR and a lot of other stuff I haven't done.

    Please let me know what do you think is the average amount of pre-requsite knowldge to go through the paper. I think my professor seemed to have rushed into giving me this paper:

    ArXiv link: http://arxiv.org/pdf/1508.07664v2.pdf

    PRL link: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061302

  2. jcsd
  3. Jun 20, 2016 #2


    Staff: Mentor

    It does look to me like background in GR would be needed to follow this paper. Specifically, you would need to at least have some exposure to the Einstein Field Equation, the physical meaning of the stress-energy tensor, the meaning of isometries and Killing vector fields, and the ADM formalism. Any GR course or textbook will cover the first three (in fact Sean Carroll's online lecture notes, which are free, cover them). The last item might not be covered in all sources; it's covered in MTW, but MTW is very comprehensive. (I can't remember offhand how much it is covered in Wald.)
  4. Jun 21, 2016 #3


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    Well, my two cents: I think your professor had a wrong judgement. You definitely need GR to understand that paper.
  5. Jun 21, 2016 #4


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    Well, I'd address the professor again and ask him about sources, from where to learn the needed background. The length restriction of PRL doesn't make these papers easy to follow for the non-expert anyway (although it's most probably very interesting and high-quality research given that it's published in PRL). So I'd ask for additional background material and/or help with questions.
  6. Jun 21, 2016 #5


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    I don't think he means that no GR is needed. He is only talking about the prerequisites from QFT. You need only scalar field theory and nothing more complicated from QFT. The GR is probably understood, or he assumes that you know some say you've taken a course.
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