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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Bit threads as noisy quantum channels

In literature on the holographic duality, recently a new way of looking at the Ryu-Takayanagi formula has been presented, where the minimal surface area has been replaced by the maximum number of "bit-...
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What is the physical analog of the projection in Holographic Principle hypothesis?

I am a layperson and do not have a good understanding of the background elements of this question. Please forgive and correct if I make any untrue statements. I understand that Holographic Principle ...
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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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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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Could an holographic universe consist of 3d embedded in 4d instead of 3d embedded in 2d?

In the holographic model, information about a given dimension can be embedded in a lower dimension, so our 3d universe could be considered as a 2d one. Could it happen the other way? I mean, could the ...
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AdS/CFT phenomenology and realistic FRW model building

Are there any examples of realistic holography (likely as a de Sitter type Universe: as it approximates FRW / is an FRW solution without baryonic and dark matter). I don’t see why one wouldn’t be ...
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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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How to show that Chern number gives the amount of edge states?

When talking about topological insulator and talking about bulk-edge correspondence, it seems to be widely accepted conclusion that the band Chern number (winding number) is equal to, when the ...
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dS/CFT in a positive curvature universe

Since Maldacena ground breaking theoretical discovery, have there been any succesfull efforts to try to transpose the AdS/CFT duality to our universe (not an AdS)?
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Wilson loop in AdS/CFT : string interpretation

It is well known that Wilson loop is a quite hard observable to compute. In the case in which the QFT is dual to a gravitation theory in AdS space, we can use holography to compute the Wilson loop, ...
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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 ...
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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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Reduction from PEPS to MERA possible?

Multi-scale entanglement renormalization ansatz (MERA) includes two kinds of isometric tensors, disentanglers and isometries. Thus tensors in MERA are by definition composed of isometries. Meanwhile ...
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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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Variation of scalar field action

I am reading Polchinski's review on AdS/CFT . I have a very simple question, and please help me out. Thanks in advanced. The question is about formula (3.19). The scalar effective bulk action is ...
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Why is chaos a common property of thermal systems?

https://arxiv.org/abs/1811.06949 pg 3 mentions that chaos is a common property of thermal systems. Can someone please explain why that is? While looking at [1], I found that indeed most examples ...
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Given observer is in the center of the cosmic horizon, and in holography all objects are mapped, where he is then mapped on the horizon?

Since the observer is in the center of the cosmic event horizon sphere (of an approximately de Sitter space) and according the Holographic principle the event horizon has mappings of all inside ...
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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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Where can I find the calculation of the holographic dual to the circular 't Hooft loop?

I know that for a Wilson loop, in the fundamental representation, the dual is a string worldsheet ending on the loop at the boundary of AdS. Similarly, I guess that the object corresponding to ’t ...
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Holographic entanglement entropy (Thermal case)

I'm trying to calculate the entanglement entropy in CFT2/AdS3 in the thermal case for a finite interval (-a,a). I'm reading the paper of Takayanagi and Rangamani (2016): https://arxiv.org/pdf/1609....
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Event horizon area and entropy content of a black hole

I am aware that the entropy content of a black hole is proportional to the area of its event horizon, and that this can be boiled down to the bit content of a Planck area on the horizon, but I have ...
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Can anyone explain the Planck area?

First of all, I am not an expert. I was reading about the holographic principle and came across the Planck area. It says that Planck area is the square of Planck length and there were some pictures ...
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Do large $N$ free fermion or WZW theories have a holographic dual in $AdS_3/CFT_2$?

I was wondering if for $N$ free Dirac fermions (or equivalently by bosonization, $N$ free bosons or an $SU(N)_1$ WZW theory plus an extra boson) have a holographic dual description via $AdS_3/CFT_2$? ...
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Information containable in a volume depends on surface area, but a volume of space can contain a volume with a bigger surface area?

The holographic principle has me confused. I'm wondering, if a volume can contain more information if it has a larger surface area, how can it be that a volume with a bigger surface area can be ...
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Holographic duals of (super)gravity sigma models

Consider a (super)gravity theory on asymptotically AdS spacetime $N$ with fixed conformal boundary $\partial N$ coupled to scalars $\phi_i$ taking values in a manifold $M$, possibly in addition to ...
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Do Holographic Screens eliminate the need of finding holographic dualities?

There are various models in physics based on the famous holographic principle (https://en.wikipedia.org/wiki/Holographic_principle) This does not always work since in these models we must find a ...
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Is Randall-Sundrum model background independent?

Randall-Sundrum model (https://en.wikipedia.org/wiki/Randall%E2%80%93Sundrum_model) is related on string theory. String theory can be background independent (https://en.wikipedia.org/wiki/...
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Holographic principle where it stops and why

I just read "Black hole wars" by L. Susskind. Essentially he claims that a boundary contains all the information about the volume it encompasses. He proclaims this the holographic principle (HP). My ...
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K theory and Holography

I have a general or overview question related to charges on D- Branes lies in the K theory of Spacetime. We normally think charges of D branes lies in the Cohomology like $D_0$ branes couple to RR-1 ...
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Can all CFT state be prepared through scale invariant MERA

It is known that in numeric computation, scale invariant MERA is useful for representing a CFT vacuum state. Is the converse true? i.e. all CFT vacuum state (the quantum state with translation and ...
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Different duality-correlations in holographic principle?

I found an interesting article "Surface/State Correspondence as a Generalized Holography" (https://arxiv.org/abs/1503.03542) If I understood it well, the authors proposed this model to generalize the ...
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What relation exists between Wolfram's model of the Cellular Automata universe and the Holographic Principle and the Bekenstein Bound?

Are computational models of the universe, like Stephen Wolfram's cellular automaton model of the universe (proposed in his book A New Kind of Science), somehow related to the Holographic Principle and ...
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How does this study affect the holographic principle and holographic screens?

In a recent study (https://www.nature.com/articles/s41467-018-05433-9) an important flaw in Emergent Gravity/Entropic Gravity has been spotted because it has been discovered that holographic screens ...
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Can baby universes solve the information paradox?

My question is do baby universes give us a satisfying explanation of the black hole information paradox without violating thermodynamics, or any other established/known physics? My understanding is ...
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Is there a more elementary example of the holographic principle?

Someone was telling me about the holographic principle, basically he said that the state of a system is determined entirely by the values of various physical quantities on its boundary. This is not ...
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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?
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How to solve the equation of motion of the minimal surface for spherical subsystems in AdS?

In order to compute the holographic entanglement entropy for a spherical subsystem in AdS using the Ryu-Takayanagi conjecture, one needs to solve the following second order nonlinear differential ...
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Quenched systems - disorder average (SYK model)

In a system with quenched disorder one is usually looking for self-averaging quantities, i.e., quantities such that the average over the couplings produces a ``typical" configuration in the ...
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Is there any GENERAL symmetry behind holography and dualities?

Holography tells that a theory with gravity in D-dimensions is equivalent to a field theory in D-1 on the boundary. Similarly, after the second string revolution, we know there are symmetries called ...
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Non-trivial content of AdS/CFT for a generic EFT on AdS

I have a very generic and naive question on the actual content (and usefulness) of the AdS/CFT conjecture in the low energy approximation where one considers a low energy QFT on AdS, comprising ...
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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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What path to take to learn about the holographic principle? [closed]

I'm looking for less of a recommendation on resources for a specific topic, and more for a general path of what to learn to get to a certain topic. If there's a better place to ask this or tag to use, ...
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Standard references in (holographic) entanglement entropy literature (Part 2)

This is a continuation of this previously unanswered question, Standard references in (holographic) entanglement entropy literature (Part 1) I am wondering as to what are the standard references that ...
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Gauge and global symmetries in Chern-Simons/WZW correspondence

I am trying to understand how bulk gauge symmetry in 3d Chern-Simons theory becomes a global symmetry in the boundary 2d WZW theory. In particular, I am trying to understand the papers by Elitzur et ...
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Is there any well-known holographic duality that allows wormholes and CTCs to exist?

Is there any well-known holographic duality (like AdS/CFT or holographic principle in string theory/black holes) that contains wormholes and Closed Timelike Curves? I was discussing this with a ...
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Standard references in (holographic) entanglement entropy literature (Part 1)

While writing a paper, I am wondering as to what are the standard references that one refers to for these various facts about entanglement entropy. I want to know as to what are the papers one should ...
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Would Bekenstein bound disappear in some holographic models?

In Holographic principle models there's a limit to the information that the system can store known as the "Bekenstein bound". In physics, the Bekenstein bound is an upper limit on the entropy S, or ...
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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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Why can AdS/CFT correspondence be applied to condensed matter systems when their space is not anti-deSitter?

The AdS/CFT correspondence postulates a duality between string theory of gravity and a CFT on an AdS background. This duality is employed in some condensed matter systems. I was wondering why it is ...
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System's mass and holographic boundary

Can mass map onto a holographic boundary in AdS(or dS)/CFTs? In particular, might the mass of a system vary directly with the surface area of a characteristic holographic boundary? I'm guessing maybe ...