Questions tagged [ads-cft]

AdS/CFT is a special case of the holographic principle. It states that a quantum gravitating theory in Anti-de-Sitter (AdS) space is exactly equivalent to the gauge theory/Conformal Field Theory (CFT) on its boundary.

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1answer
992 views

Deriving entanglement entropy from Renyi entropy

My questions are based on this paper - http://arxiv.org/abs/0905.4013 Firstly I want to know as to whether some assumptions are needed about the relationship between the systems $A$ and $B$ for the ...
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1answer
128 views

Deconfinement at high T $\leftrightarrow$ spontaneous breaking of the center of the gauge group

I am reading Witten's "Anti-de Sitter Space, Thermal Phase Transitions, And Confinement In Gauge Theories" (see here), in which he connects the confinement-deconfinement transition in $\mathcal{N}=4$ ...
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2answers
387 views

Lax-Pair for principal chiral model

This question concerns Eq. (2.10) of the paper http://arxiv.org/pdf/hep-th/0305116v2.pdf by Bena, Polchinski and Roiban. In section 2.1 they are showing that the infinite number of conserved ...
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1answer
75 views

Duality between gravitation and $O(N)$ model

Does there exist any gravity dual theory for theory with $N$-component scalar field with $(\phi^2)^2$ interaction?
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1answer
81 views

Electrons with disorder & something like AdS/CFT duality

I know that consideration of electrons with disorder can be based on Feynman diagrams with disorder lines. In this approach, only non-crossing diagrams are important and give contribution to self-...
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2answers
947 views

Why is there a Cardy formula in 2D CFT?

In 2d CFTs, we have the Cardy formula which tells us the number of states, which can be derived from the partition function by using modular invariance. What special property of 2D CFTs make it ...
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1answer
260 views

How to calculate the Wald functional?

I want to calculate the Wald functional for arbitrary higher curvature Lagrangians - like getting equation 6.31 from 6.30 in this paper. A priori the above looks like an extremely complicated ...
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1answer
413 views

What are “local degrees of freedom in gravity”, and why do they lead to fixed energy densities?

I am reading Jan de Boer's review of the AdS/CFT correspondence and I quote from end of page 1, where he is talking about equivalence of $(d+1)$-dimensional gravity to $d$-dimensional field theory “...
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1answer
143 views

A coincident stack of D3 branes vs a shell of them

I would in general like to understand how to derive the low energy metrics to describe D-brane configurations. Any pedagogic reference which explains the method? In particular I have in mind these ...
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56 views

What are the necessary conditions for a CFT to have a holographic dual? [duplicate]

The number of degrees of freedom of a CFT is given by its central charge $c$. From the bootstrap point of view, any CFT is characterized by the knowledge of its "CFT data", i.e. the scaling dimensions ...
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61 views

How I can get the numerical factor in the relation between string coupling and YM coupling?

I'm trying to understand some references about Wilson loops being used to test AdS/CFT. Some of them are Nadav Drukker, David J. Gross: An Exact Prediction of N=4 SUSYM Theory for String Theory ...
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1answer
329 views

Circular Wilson Loop in AdS/CFT

I'm trying to get the AdS solution to the circular wilson loop. The standard AdS metric is: $ds^2 = \frac{L^2}{z^2}(\eta_{\mu \nu} dx^{\mu} dx^{\nu} + dz^2)$ If I take the circle of radius R at ...
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1answer
309 views

Maldacena's decoupling argument

I am a bit confused about Maldacena's original decoupling argument. There are two different low energy (i.e, $\alpha^\prime \to 0$) descriptions of the stack of D3-branes: $\mathcal{N}=4$ SYM and ...
3
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1answer
556 views

What do we mean by “typical state”?

My question is somehow simple, but not trivial. I'm reading many articles about the ER=EPR correspondence. There are some articles which study this proposal from a field theory point of view (one ...
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2answers
734 views

Symmetry transformation in AdS space

In AdS/CFT papers the action of the SO(D,2) symmetry is usually given at the boundary where the transformations are just the conformal transformations (Poincare, scaling and special) for D+1 ...
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1answer
67 views

Why we use majorana fermions the SYK model?

Does anyone know why do we use majorana fermions in the SYK model. why we can't use Dirac spinors? Is there any specific reason why we use majorana fermions in this model?
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1answer
379 views

Applicability of Ryu-Takayanagi formula for boundary regions which do not belong to constant time slice

While reading article "Entanglement Entropy of Extremal BTZ" I saw a phrase: In the more general case where the entangling interval does not lie in a single time slice of the boundary, the Ryu–...
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1answer
303 views

Large $N$ expansion vs AdS/CFT

I'm beginning to learn AdS/CFT and I have an elementary question. It is said that since it is very hard to calculate 4 point and above correlators in a strongly coupled CFT, we can use instead the ...
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1answer
161 views

Implication of non-positive tripartite information

Hayden et al 2011 showed that tripartite information is non-positive given Ryu-Takanayagi formula. (For definition of tripartite information, see for instance section 4.4 of this paper) Is there ...
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1answer
194 views

Massless limit to massive scalar in AdS space

I was trying to solve massive scalar wave equation in AdS spacetime (or rather in BTZ). I noticed few funny things : The $m\to 0$ limit to the solution is subtle. One of the two independent ...
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1answer
181 views

What is the advantage of AdS/CFT in studying strong coupled system comparing with the lattice method

I often heard AdS/CFT correspondence provides a powerful framework to study strong coupled system, which perturbation is not applicable. However, lattice method still works in non-perturbative domain. ...
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60 views

Dirac bracket and Poisson bracket, asymptotic symmetry

I am reading the paper arXiv:9906126. https://arxiv.org/abs/gr-qc/9906126 on the symmetry algebra at horizon (see also well known work done by Brown and Henneaux about the asymptotic algebra of AdS$...
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157 views

What is the CFT dual of the stress tensor in the bulk?

I am new to AdS/CFT. I know that the dual of the bulk metric is the CFT stress tensor but what about the dual of the bulk stress tensor? I mean in principle one can extrapolate whatever bulk fields to ...
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Aharony-Bernman-Jafferis-Maldacena (ABJM) and k=1 Chern Simons matter

I have read recently that the partition function / half-BPS wilson vev (w/ NG probe) of a Chern-Simons matter theory with N=6 U(N)k x U(N)-k super-conformal symmetry (ABJM) on S3 is proportional to ...
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Phase transition in a generalised SYK model

Crossposted from math.stackexchange. (Link: https://math.stackexchange.com/questions/2848558/is-this-function-meromorphic) Question Let $$e^{g\left(\tau,T,J_1,J_2\right)}=\frac{2}{\left(\frac{J_1}{...
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Holographic dualities and strong subbadditivity of entanglement entropy

Recent analysis of inequalities satisfied by entanglement entropy in AdS bulk duals have led to establishing an equivalence between Strong Subadditivity and the Null Energy Condition (NEC) How hard ...
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Is Wilson loop particle heavier than black hole in AdS-CFT at finite temp?

Finite temperature is introduced in the Ads Space by inserting a black hole. In the Ads-CFT correspondence, the Wilson loop is at $u \rightarrow \infty$. But the black hole horizon itself would be at $...
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When to trust Holography?

AdS/CFT correspondence allows us to compute $n$-point functions of a CFT by means of solving on-shell gravitational action in anti-de Sitter space. If I understand correctly, considering classical ...
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1answer
172 views

Distinction between holographic entanglement entropy and thermal entropy

Given a system $A$ and its complement $\bar{A}$, we know that the entanglement entropy is given by $$ S_A = - \text{Tr} ( \rho_A \log \rho_A ), $$ where $\rho_A$ is the reduced density matrix ...
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66 views

Rotating Branes and AdS/CFT

Do we have an extension of the AdS/CFT correspondence for rotating branes? Are the rotating branes, the supergravity analog of the Kerr Black Holes in General Relativity? What are the most ...
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1answer
350 views

Sub-Ads scale resolution of pluperfect tensor network

I am currently reading article "Bidirectional holographic codes and sub-AdS locality". [I] This article presents tensor networks which are built from so called pluperfect tensors. Authors claim that ...
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1answer
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What is a Witten diagram?

Recently I heard the terminology of Witten diagram. Studying QFT, I frequently see Feynman diagrams and use them to compute scattering amplitudes, one-loop corrections and so on. In string theory ...
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Fluctuating string in AdS black hole

People frequently use fluctuating string in AdS black hole (see 1,2,3 etc) to study dynamics of a "free external quark" in quark-gluon-plasma (QGP) at finite temperature. The background black hole ...
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322 views

Boundary stress-energy tensor form ADS/CFT

In "Gravitational Dynamics From Entanglement "Thermodynamics"" by Lashkari/McDermott/Van Raamsdonk, the authors derive the linearised Einstein equations from ADS/CFT. At page 6 they use $$t_{\mu{\nu}}(...
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Gravity dual of N free scalars in 2D

I have a very basic (and might be very naive) question. What should be the dual gravity description of $N$ (with $N>>1$) free scalars in two dimensions? I was wondering whether it would be ...
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Are temperature and chemical potential of a black hole independent quantities?

I am a bit confused about the independent parameters in a charged black hole in AdS spaces. From equation (63) of this lecture notes we see that the temperature (T) of the black hole has chemical ...
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208 views

Geodesic approximation and Euclidean continuation

I recently read many articles in the context of the AdS/CFT correspondance in which the geodesic approximation is used (see for example section 3.5 here). The correlator between two boundary operators ...
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120 views

How can we see that there is superconductivity/superfluidity in the boundary theory in the holographic principle?

For example in the models for holographic superconductors we can calculate the conductivity. Also there is an energy gap. I can understand that it describes a superconductor. However I have also heard ...
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99 views

Is it possible to build up holography in a closed manifold, i.e., in a manifold with a mathematical boundary?

I was wondering about the AdS/CFT correspondence basics. It is constructed on the idea of conformal compactification, in which a open manifold $M$ is homeomorphic related to a closed one $N$ through a ...
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299 views

Questions on entanglement entropy

If the spatial entangling surface is $M$ then it seems that one way to get the entanglement entropy is to think of the QFT on the manifold $S \times M$ where $S$ is a 2-manifold with the metric, $ds^2 ...
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315 views

Moduli Space of $\mathcal{N}=4$ SYM on $\mathbb{R} \times S^3$

When we define $\mathcal{N}=4$ SYM on flat Minkowski space, the supersymmetric vacua are parametrized by scalars living in the cartan subalgebra of the gauge group. A generic point in the moduli space ...
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74 views

Free energy of the critical U(N) model

Can someone help explain how the equations 30, 31 and 34 were obtained in this paper. At a conceptual level I am wondering looking at equation 34 as to if they mean that $\lambda$ is somehow the ...
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212 views

Group theory notation used in physics (AdS/CFT)

This in the context of the AdS/CFT correspondence. I am reading this review on AdS/CFT Aharony et. al. (The MAGOO review) The abstract can be found here Equation (2.50) of the above paper lists the $...
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155 views

Construction of the supergravity side explicitly in gauge/gravity dualities

Although the motivation of this question comes from the AdS/CFT correspondence, it actually is related to a more general principle of gauge/gravity duality. We know from Maldacena's conjecture that a $...
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345 views

Conformal symmetry of Navier-Stokes?

This question is in reference to the paper arXiv:0810.1545 Can someone help understand this scaling argument and the proof(?) that there is a conformal symmetry in Navier-Stoke's equation? (..am I ...
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684 views

Correlators at large N and large N factorization

I am having this very basic problem. In e.g Maldacena's AdS/CFT review (0309246) (page 5), he has defined operators as $\mathcal{O}=N\,{\rm tr}[f(M)]$ for some matrices $M$ and got the connected ...
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159 views

Role of AdS/CFT correspondence in the context of integrability

I was wondering how the AdS/CFT correspondence fits in the context of integrability. As I understand, the AdS/CFT correspondence postulates a duality between gravity theories and CFT's. If one theory ...
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2answers
1k views

Why does AdS/CFT with non-zero temperature correspond to a black hole in the bulk?

Is there a good intuitive explanation on why AdS/CFT with non-zero temperature corresponds to a black hole in the bulk? And what is the role of temperature and chemical potential in this black hole?
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Large-N factorization of single-trace operators

Does anyone know where I can find a pedagogical explanation of large-N factorization in SU(N) gauge theories or nonlinear O(N) sigma models (in the latter case the trace corresponds to a dot product). ...
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1answer
129 views

Why do we say that AdS/CFT is a background independent definition of string theory?

It is usually said that AdS/CFT is a background independent definition of string theory, how this concept emerge from the AdS/CFT correspondence? We can define string theory on other manifolds ...