Questions tagged [holographic-principle]

The Holographic principle is a principle of string theories and a supposed property of quantum gravity that states that the information within a region is exactly described by that on its boundary. DO NOT USE THIS TAG for a photographic hologram.

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79
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8answers
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Why is information indestructible?

I really can't understand what Leonard Susskind means when he says in the video Leonard Susskind on The World As Hologram that information is indestructible. Is that information that is lost, through ...
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3answers
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Why is Sachdev-Ye-Kitaev (SYK) Model model important?

In the past one or two years, there are a lot of papers about the Sachdev-Ye-Kitaev Model (SYK) model, which I think is an example of $\mathrm{AdS}_2/\mathrm{CFT}_1$ correspondence. Why is this model ...
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2answers
526 views

Newtonian gravity from the holographic principle?

Can one understand Newton's law of gravitation using the holographic principle (or does such reasoning just amount to dimensional analysis)? Following an argument similar to one given by Erik ...
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Has the black hole information loss paradox been settled?

This question was triggered by a comment of Peter Shor's (he is a skeptic, it seems.) I thought that the holographic principle and AdS/CFT dealt with that, and was enough for Hawking to give John ...
16
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2answers
570 views

Holographic Renormalization in non-AdS/non-CFT

In AdS/CFT, the story of renormalization has an elegant gravity dual. Regularizing the theory is done by putting a cutoff near the conformal boundary of AdS space, and renormalization is done by ...
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Are Stokes' theorem and Gauss's theorem examples of the Holographic Principle?

Before I write this question, I'd want to say that I've read this question , and Lubos Motl's answer to it (I found it through the "Questions that may already have your answer"). ...
16
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1answer
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How many bits are encoded on the surface of the smallest black hole?

Here's my guess ($157\, \textrm{bits}$) and how I got there. Please feel free to disregard completely and give your own answer. My understanding (please correct any wrong assumptions as there may be ...
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4answers
993 views

What exactly does the holographic principle say?

Does the holographic principle say given a spatially enclosing boundary satisfying the Bousso condition on expansion parameters, the log of the number of microstates in its interior is bounded by $\...
14
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2answers
746 views

Has Verlinde's theory made significant advance recently?

In 2010-2011, Verlinde's theory for explaining gravity as emergent from thermodynamics started to get known in the physics community. It was (and seemingly still is) lacking evidence, and faced ...
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1answer
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Introductory examples of AdS/CFT duality

I would like to know, what are the simplest/starting/basic examples that are typically used to introduce students to how AdS/CFT really works? (not the MAGOO paper, as I am not sure it has concrete ...
12
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Is quantum uncertainty a function of how matter is distributed in the universe?

As an outcome of his PhD thesis work, Richard Feynman and John Wheeler wrote a series of papers on how the kickback on an electron as it emits a photon can be modeled accurately as the result of an "...
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3answers
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Information encoded on the surface of a black hole

If an object that enters a black hole has its information content frozen at the event horizon, in what sense is it frozen? The usual analogy is of a hologram encoded in 2d which can be decoded into a ...
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Candidates for holographic QFT of 4D Einstein gravity

If we are to believe that holographic principle holds over a wide number of dimensions, and gravitational theories, but specially, those that are relevant to our universe, then there must be some 3D ...
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7answers
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What are cosmological “firewalls”?

Reading the funny title of this talk, Black Holes and Firewalls, just made me LOL because I have no idea what it is about but a lively imagination :-P (Sorry Raphael Bousso but the title is just too ...
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1answer
732 views

What does AdS/CFT have to say about quantum gravity in our world?

The Ads side of the AdS/CFT correspondence is a model of quantum gravity in 5 dimensional antidesitter space. What can it say about quantum gravity in our 4-spacetime dimensions? Or is it just a toy ...
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In what sense does the universe have an outer edge?

I'm having trouble understanding something about Susskind's Holographic principle. Susskind speaks about the surface of the universe? In what sense does the universe have an outer surface? I'm a ...
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1answer
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How does the holographic principle imply nonlocality?

For example in the discussions here and here there are comments by Ron Maimon: Your complaint about locality would be more serious if holography didn't show the way--- the CFT in AdS/CFT produces ...
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Holographic principle and Wheeler's bag of gold

How is it possible to explain "bag of gold" spacetimes (see Marlof) such that the ideas are compatible with AdS/CFT and the holographic principle?
9
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1answer
225 views

Why isn't there heterotic holographic QCD?

I think the question speaks for itself... Top-down holographic QCD, like Sakai-Sugimoto, always involves the Type II string. There are one or two papers on hQCD using the Type 0 string. But I can't ...
9
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1answer
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What is Mathematical formulation of Holographic principle? [closed]

What is Mathematical formulation of Holographic principle The holographic principle is a property of quantum gravity and string theories which states that the description of a volume of space can ...
9
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460 views

Relation between CS/WZW and AdS/CFT

One precise example of realization of the holographic principle is the CS/WZW correspondence, which relates 3d Chern-Simons theory with the 2d Wess-Zumino-Witten model. As explained for example in ...
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Why is the AdS/CFT approach to superconductors rarely cited in condensed matter publications?

Let me put things into perspective by comparing with other applications of string theory. Nowadays review papers written by cosmologists about inflation models often discuss string theory scenarios ...
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1answer
696 views

Why holographic renormalization?

Why is there a need to perform holographic renormalization for the normal $AdS_5\times S^5$/CFT$_4$ correspondence if the brane theory is conformal? Since the flow along the AdS direction $r$ is ...
8
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1answer
421 views

Is there an equivalence between information, energy and matter?

Consider the physical world as made of information, with energy and matter as incidentals. This statement must be placed in the context of the holographic principle and the works of Bekenstein ... ...
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394 views

Generalisations of AdS/CFT with string theory on both sides

From my previous post, I found out from the comments that there are various generalisations of AdS/CFT with different things replacing the CFT on the RHS; such as AdS/CMT, AdS/QCD, and also with ...
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Maximum Possible Information in the universe?

I remember hearing about this in one of the programs in discovery science. The physicist claimed that the maximum possible information in the universe is $10^{10^{123}}$ whereas the maximum possible ...
7
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1answer
473 views

Charged CFT observables and AdS/CFT

I have a simple question regarding the holographic dictionary when mapping operators on the CFT side to those in AdS. One piece of the dictionary is that a global symmetry maps onto a gauge symmetry ...
7
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1answer
216 views

Material implementations of the holographic principle

I'm afraid this question is a little too open-ended, but bear with me while I find a better formulation. carbon allotropes (like fullerenes and graphene) are regular patterned. Conduction bands of ...
7
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1answer
728 views

How is the 'cluster decomposition principle' implemented in holographic theories?

Since holographic theories are non-local by definition, how is this principle implemented? Naively, it seems to me it is not, at least, in some sense. I would appreciate an explanation as simple ...
7
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1answer
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BEC for holography?

I am spending some time reading about Bose-Einstein condensation. I want to know if it is possible to use atom lasers to realize the kind of holography traditionally associated with nano-fabrication. ...
7
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1answer
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What is the physics behind “Bulk-edge correspondence”?

There is a frequently mentioned concept in the field of topological insulator called "bulk-edge correspondence" or "bulk-boundary correspondence", which basically gives the relationship between the ...
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1answer
880 views

Does the universe obey the holographic principle due to Stokes' theorem?

Does the universe obey the holographic principle due to Stokes' theorem? \begin{equation} \int\limits_{\partial\Omega}\omega = \int\limits_{\Omega}\mathrm{d}\omega. \end{equation} Can this ...
6
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3answers
354 views

What happens at the center of a black hole according to holographic theory?

As far as I understand, the AdS/CFT correspondence proposed by Maldacena is an exact duality to a four-dimensional theory, which interpolates between one well-defined conformal field theory in the UV ...
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2answers
368 views

Holographic principle “inside-out view”

From the perspective inside a black hole: Is information about everything outside a black hole - the rest of the cosmos - represented on the inside of the (event) horizon too? NB. I realize it is the ...
6
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1answer
411 views

Flat Space Limit of AdS/CFT is S-Matrix Theory

In an answer to this question, Ron Maimon said: The flat-space limit of AdS/CFT boundary theory is the S-matrix theory of a flat space theory, so the result was the same--- the "boundary" ...
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646 views

The surface area to volume ratio of a sphere and the Bekenstein bound

I am trying to relate the surface-area-to-volume-ratio of a sphere to the Bekenstein bound. Since the surface-area-to-volume-ratio decreases with increasing volume, one would surmise that, per unit of ...
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1answer
335 views

What is relation between Holographic principle and Hologram?

What is relation between Holographic principle and Hologram? The holographic principle is a property of quantum gravity and string theories which states that the description of a volume of space can ...
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2answers
2k views

Why is information in a volume proportional to it's surface area?

I read the wiki article on the holographic principle, but it never answered this question. Can anyone explain the math that leads to this conclusion?
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Information loss in a black hole

How does the Holographic Principle help to establish the fact that all the information is not lost in a black hole?
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865 views

Is there anything actually inside a black hole, do they actually exist?

When objects fall into a black hole, observers outside the black hole will never see the object cross the event horizon because the object's time slows down and will stop at the event horizon. The ...
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1answer
658 views

The Universe is a Hologram

First my background: no physics, but Ph.D. in math. I was reading this article on Slashdot. It links to this Wikipedia page. The content of the Slashdot article is that some physicists believe the ...
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1answer
81 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 ...
5
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1answer
173 views

Where is the proof of AdS/CFT?

People have been using the AdS/CFT correspondence for some time now. But I have yet to see a formal proof. Does one exist? Or is it still a conjecture? (Well I have seen claimed proofs). I have seen ...
5
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1answer
98 views

Derivation of Eq. 7.12 in the review paper of Kraus

I'm reading "Lectures on black holes and the $AdS_3/CFT_2$ correspondence" by Kraus. http://arxiv.org/abs/hep-th/0609074 I don't know how one can obtain Eq.7.12. My stupid question is how to obtain ...
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1answer
256 views

Holography on non-AdS spacetime

I have a question regarding AdS/CFT and what it teaches about our world. AdS/CFT if often treated as our best tool to explore quantum gravity, and people have worked very hard in trying to understand ...
5
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1answer
328 views

How rigorous is the description of the edge of the Kitaev Honeycomb as a CFT?

My understanding of the Kitaev honeycomb model is that high-level abstract properties (anyons and their braid statistics) can be seen to emerge the microscopics of the model (fermions and vortices). ...
5
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1answer
281 views

Are not the field equations proof of the holographic principle?

The field equations (e.g. Schrödinger’s/Maxwell’s) describe the four-dimensional universe as the time evolution of a three-dimensional system. This implies that the universe contains only three ...
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1answer
377 views

$AdS_3$ soliton of Witten - for Hawking-Page transition

Are there explicit AdS$_3$ soliton solution? in the sense of Witten's Anti De Sitter Space And Holography and Hawking-Page transition paper, by doing a $$\tau_E, y ,r \to y, \tau_E ,r$$ from a ...
5
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1answer
672 views

Is spacetime an illusion?

In consistent histories, for gauge theories, can the projection operators used in the chains be not gauge invariant? In quantum gravity, for a projection operator to be gauge invariant means it has ...
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0answers
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What role does SUSY play in gauge/gravity duality?

This question arises in my project of finding the conformal field theory dual to the bosonic part of the Yang-Mills theory, i.e. non-supersymmetric large $N$ YM theory. Supersymmetry is a constant ...

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