Quantcast
  • Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.

News

PO is now at the Physics Department of Bielefeld University!

New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback

Attributions

(propose a free ad)

Site Statistics

205 submissions , 163 unreviewed
5,047 questions , 2,200 unanswered
5,345 answers , 22,709 comments
1,470 users with positive rep
816 active unimported users
More ...

  AdS/QCD, Light-Front Holography, and the Non- perturbative Running Coupling

Originality
+ 0 - 0
Accuracy
+ 0 - 0
Score
0.00
1357 views
Referee this paper: arXiv:1002.4660

Please use comments to point to previous work in this direction, and reviews to referee the accuracy of the paper. Feel free to edit this submission to summarise the paper (just click on edit, your summary will then appear under the horizontal line)

(Is this your paper?)


This 2010 paper by S.J. Brodsky, G.F. de Teramond and A. Deur shows that the combination of Anti-de Sitter space (AdS) methods with light-front (LF) holography provides a remarkably accurate first approximation for the spectra and wavefunctions of meson and baryon light-quark bound states.

''The resulting bound-state Hamiltonian equation of motion in QCD leads to relativistic light-front wave equations in terms of an invariant impact variable ζ which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. The eigenvalues give the hadronic spectrum, and the eigenmodes represent the probability distributions of the hadronic constituents at a given scale. A positive-sign confining dilaton background modifying AdS space gives a very good account of meson and baryon spectroscopy and form factors. The light-front holographic mapping of this model also leads to a non-perturbative effective coupling $α_s^{AdS}(Q^2)$ which agrees with the effective charge defined by the Bjorken sum rule and lattice simulations. It displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale ∼1 GeV. The resulting β-function appears to capture the essential characteristics of the full β-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD.''

summarized by Arnold Neumaier
paper authored Feb 23, 2010 to hep-th by  (no author on PO assigned yet) 
  • [ revision history ]
    recategorized Aug 27, 2014 by Arnold Neumaier

    I read in the introduction: "The AdS/CFT duality provides a gravity description in a (d+ 1)-dimensional AdS space-time in terms of a at d-dimensional conformally-invariant quantum field theory defined at the AdS asymptotic boundary. Thus, in principle, one can compute physical observables in a strongly coupled gauge theory in terms of a classical gravity theory."

    I think there may not be any "thus" nor "in principle" here. CFT and QCD are different things. I do not see any logic in their statement, even though later on they deform something and use approximations for other things in order to apply some tools. The statement itself must be "deformed", IMHO.

    @VladimirKalitvianski you seem not to be familiar enough with the topics of the paper at a technical level. If you have questions about the basics of  AdS/CFT, holography, etc please ask them in the Q&A part (if they are on topic for PhysicsOverflow). The comments in the Reviews section are not intended to clarify basic mis/non-understandings of readers but for people, who are sufficiently knowledgeable about the topics at hand, to discuss the paper at research-level.

    @VladimirKalitvianski : in your citation, the "thus" is justified because the "d-dimensional conformally-invariant boundary defined at the AdS asymptotic boundary" is indeed "a strongly coupled gauge theory". Of course, this theory is not pure QCD, what you cite does not claim that it is (the statement is  logically correct), and if one wants to deduce something on a QCD like theory, one has to work (and it is the subject of the paper).

    @40227: Thanks, I did not know it.

    Your Review:

    Please use reviews only to (at least partly) review submissions. To comment, discuss, or ask for clarification, leave a comment instead.
    To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
    Please consult the FAQ for as to how to format your post.
    This is the review box; if you want to write a comment instead, please use the 'add comment' button.
    Live preview (may slow down editor)   Preview
    Your name to display (optional):
    Privacy: Your email address will only be used for sending these notifications.
    Anti-spam verification:
    If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
    p$\hbar$ysics$\varnothing$verflow
    Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).
    Please complete the anti-spam verification




    user contributions licensed under cc by-sa 3.0 with attribution required

    Your rights
    ...