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A Prospects in AdS/CFT theory

  1. Aug 2, 2018 #1
    Lately AdS/CFT seems to have been a very promising tool to simplify calculations in HEP (ex. quark-gluon plasma) and offer some insights into quantum gravity. I was considering doing a Master or PhD thesis in this field, but I'm wondering if the prospects are more reasonable than just string theory or it would be better to go towards something more concrete like QCD lattice or SM precison tests. I've read mixed reviews about it being a very hot topic of research (especially in the US) while others say it barely makes testable predictions and it is better regarded as a mathematical theory.

    In particular, my goal is to find a good post-doc after graduate studies, or at least find a job in the private sector but still be involved in research in HEP. Moreover, I'm both interested in the mathematical beauty of physics theories as well as their experimental confirmation.
  2. jcsd
  3. Aug 3, 2018 #2
    AdS/CFT is (in my opinion) the apex of - mathematical physics? physical mathematics? - at this point. But it is not yet directly relevant to fundamental real-world physics. AdS is a background geometry in which quantum gravity can be studied in more depth than ever before, owing to the CFT duality; but AdS is not the geometry of the real world. We should expect that eventually, an equally substantial interpretation of the holographic principle for flat space and de Sitter space will be found, and that aspects of AdS study will help us find the version of holography that is more relevant to reality.
  4. Aug 3, 2018 #3


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    I'm no expert, but if I have to bet on the future, I'd say within some decades we'll regard holography as a duality that gave us insight into the structure of spacetime. I'm sceptical about all these "confirmations of holography", see also e.g. http://backreaction.blogspot.com/2013/09/whatever-happened-to-adscft-and-quark.html . I'd study string theory and holography if you're interested in the question what spacetime really is, and are interested in the whole "spacetime emergence from quantum entanglement of yet unknown spacetime atoms"-line of research. Likewise, I think string theory will be regarded as an intermediate step and calculational tool in this question,
  5. Aug 3, 2018 #4

    Urs Schreiber

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    It is common to say that AdS/CFT is not directly relevant for realistic model building on the gravity side, if/since the observable universe is not asymptotically AdS.

    However, one of the better developed corners of string phenomenology are intersecting D-brane models, where the obervable universe is modeled on the 3+1-dimensional intersections of D6-brane worldvolumes inside a 10-dimensional bulk spacetime. For purposes of particle physics this is typically discussed in perturbative string theory where these D-branes are sitting in the ambient bulk spacetime without backreaction, but by the standard lore of black branes in string theory these D6-branes become, non-perturbatively, black branes with a near horizon geometry of the form AdS x compact.

    Hence intersecting D-brane models predict Randall-Sundrum-like cosmologies where the observable universe is confined to the asymptotic boundary inside an ambient AdS bulk spacetimes visible only to gravity (see also the references here).

    This is just the general setup of AdS/CFT duality, just subject to two qualification:
    1. it is not the bulk but the boundary which serves as a potentially realistic model;
    2. this is not one of the cases where the boundary field theory is conformal.
    Due to the second point, AdS/CFT still does not apply directly without modification, but it should be much, much closer than in speculations about deSitter/CFT duality with the realistic spacetime on the bulk side (the latter speculation seems to be far-fetched, and increasingly so).
    Last edited: Aug 3, 2018
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