• 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.


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


(propose a free ad)

Site Statistics

205 submissions , 163 unreviewed
5,054 questions , 2,207 unanswered
5,348 answers , 22,725 comments
1,470 users with positive rep
818 active unimported users
More ...

  Introduction to AdS/CFT

+ 9 like - 0 dislike

AdS/CFT seems like a really hot topic and I'd like to start reading about. I am looking for the best introduction at my level, i.e. I have a background in QFT, CFT and general relativity at the level of a master student in theoretical physics. What would you recommend me to start tackling the subject? I have been looking for resources and so far I have noticed:

-this synthetic introductory lectures by Horatiu Nastase: http://arxiv.org/abs/0712.0689

-the videos of lectures done by P. Vieira at Perimeter for Perimeter Scholar International students: http://www.perimeterscholars.org/341.html

-the subject starts entering the most recent textbooks on string theory. We have the Schwartz and Becker ( http://goo.gl/jh45U ) and also the Kiritsis ( http://goo.gl/ulEVw )

I probably missed a lot of resources, as the literature on the subject is already quite huge. I would really appreciate some advice on that, as I already had the frustration of losing my time on not-so-good books when started to learn something new, so if I could (to the best) avoid that this time...

This post imported from StackExchange Physics at 2014-03-24 05:04 (UCT), posted by SE-user Just_a_wannabe

asked Sep 13, 2012 in Resources and References by Just_a_wannabe (30 points) [ revision history ]
recategorized Apr 24, 2014 by dimension10
I would also like to add: String Theory Demystified by David McMahon, Chapter 15 link. I liked it as a good starting point to get a good overview without loosing to much time.

This post imported from StackExchange Physics at 2014-03-24 05:04 (UCT), posted by SE-user ungerade

5 Answers

+ 3 like - 0 dislike

You may find a list of reviews under the item Anti-DeSitter Space in the nice website "The Net Advance of Physics"

There is a nice review of the applications of gauge/gravity duality to the heavy ion collisions Gauge/String Duality, Hot QCD and Heavy Ion Collisions

This post imported from StackExchange Physics at 2014-03-24 05:04 (UCT), posted by SE-user unstable
answered Sep 13, 2012 by unstable (0 points) [ no revision ]
+ 3 like - 0 dislike

There is also this set of lecture notes from Raman Sundrum: 'Fixed Points to the Fifth Dimension':


This post imported from StackExchange Physics at 2014-03-24 05:04 (UCT), posted by SE-user DJBunk
answered Sep 13, 2012 by DJBunk (80 points) [ no revision ]
+ 3 like - 0 dislike

Thanks for the links above. After pursuing my research I found this quite exhaustive bibliography linking to online resources:


I hope it won't be useful only to me ;)

This post imported from StackExchange Physics at 2014-03-24 05:04 (UCT), posted by SE-user Just_a_wannabe
answered Sep 15, 2012 by Just_a_wannabe (30 points) [ no revision ]
+ 2 like - 0 dislike

I had to give a talk on AdS/CFT without knowing anything about it beforehand, and I found this set of lectures by Johanna Erdmenger extremely accessible: http://wwwth.mpp.mpg.de/members/olivers/AdSCFT-2010-01-22.pdf

It's also now part of a nice book of lectures string theory edited by Michael Haacke, Ilka Brunner

This post imported from StackExchange Physics at 2014-03-24 05:04 (UCT), posted by SE-user Judy Kupferman
answered Sep 19, 2012 by Judy Kupferman (0 points) [ no revision ]
+ 2 like - 0 dislike

The point of view of algebraic quantum field theory is given by K.-H. Rehren, hep-th/0411086. His paper defines the correspondence fully within QFT, without the need of any background knowledge of string theory. (The applications to QCD don't make use of the connection to string theory either.)

answered Aug 26, 2014 by Arnold Neumaier (15,787 points) [ no revision ]
Most voted comments show all comments

Huh, then how is the AdS side where one has quantum gravitiy discribed by this approach? In this answer, Lumo explained that QFT approximations, such as SUGRA are only valide for large t'Hooft coupling $\lambda\equiv g_{\rm YM}^2 N$ and small curvature of (the backround) spacetime. Does this algebraic QFT aproach work for all values of the t'Hooft coupling?

Hm, I am not sure if saying the QCD application of AdS/CFT is the only contact to experiment is a bit too pessimistic ... I will ping Lumo below my P.SE question about the issue to try to bring him back here ...

It is a non-sense to say that AdS/CFT has nothing to do with gravity. Another name, a bit more general, of AdS/CFT is gauge/gravity correspondence, with a gauge theory on the boundary and a gravity theory in the bulk. As correctly recalled by Dilaton, for large t'Hooft coupling, the true quantum gravity (i.e. a string theory) reduces to its low energy effective limit, i.e. a supergravity theory. Even in this limit, the theory living on AdS is a gravity theory, it is even in first approximation classical gravity theory. This is absolutely necessary for the duality to work: the dual of the stress-tensor operator of the gauge theory on the boundary is the metric in the bulk, i.e. to compute correlation functions of the stress-tensor in the gauge theory, one has to solve supergravity equations with appropriate boundary conditions. In the "applications" to the quark-gluon plasma, applying the above procedure shows that the dual of a plasma is a black hole in AdS and the results experimentally testable on quark-gluon plasma come from our knowledge of black holes. It is difficult to find something more gravitational... 

Physicists try to do both, of course - trying derivations from first principles and trying to match the data with effective theories. The former is over my head. For the latter, the AdS/QCD version in http://arxiv.org/abs/hep-ph/0602229 (which includes a scalar dilaton field but still no dynamical gravity) seems currently quite reasonable. Perhaps both approaches meet one day.

@  Arnold Neumaier: you write "as you say, gauge/gravity correspondence is something more general than AdS/CFT: The latter is a more special situation independent of gravity - the AdS metric is completely fixed and not dynamical." What is usually called AdS/CFT is a gauge/gravity correspondence with a full gravity theory on AdS. If someone wants to consider something else then it is better to find a different name.

It is true that some calculations, as the one in the paper you cite, can be done with a fixed metric  on AdS but these are only approximations. Of course, it is perfectly fine to do such computations which reduce to usual QFT on a fixed curved spacetime but it is necessary to remind that these are approximations. In the second paper of Elrich, he writes correctly (at the end of page 6) "In known holographic dualities, the higher-dimensional version of the theory always contains gravity, and the failure of the intuition that fewer dimensions implies fewer degrees of freedom is related to some unusual properties of black holes in general relativity". 

It is a general consequence of the holographic principle that the dual of the stress-tensor operator of the gauge theory on the boundary is the metric in the bulk. So if there is any non-trivial excitation in the gauge theory, there will be some non-trivial excitations of the fields on AdS which will in particular modify the metric. For some questions, it is possible to neglect this backreaction of the metric, what is done in the papers you cite. For some others, it is not possible. For example, the dual of a thermal plasma is a black hole.

''If someone wants to consider something else then it is better to find a different name.'' It is not me who chose the terminology. In all papers I saw comparisons with to actual data, it was always called AdS/CFT (occasionally in addition AdS/QCD) and it was always computed in a fixed metric. No use was made of gravity, and the basic principle can be understood without it. In the sense of duality as two essentially different descriptions of the same theory, these are already dualities. 

''it is necessary to remind that these are approximations'' - to the bigger theory, of course. But who knows if the bigger theory is exact - all of physics is approximation, unless you just study a particular theory and take it to be exact. 

Nah, I would say out of reach is a bit a strongly negative term, I would rather say it is in principle doabel, but very difficult. Probably similarly as to the problem of extracting the standard model, the space of solutions to ST have to be better understood first. I personally like explanations from first principles better than just fitting parameters to data.

Your answer

Please use answers only to (at least partly) answer questions. 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 answer 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:
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