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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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BTZ black hole as a quotient of AdS space

I am trying to understand this paper 1 and trying to reproduce some calculations and had some questions about that. In section 3.2, page 12, eq. 3.9, the authors are writing normal geodesics of an ...
Goodfellow's user avatar
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How do hyperbolic tessellations like {7,3} in Anti de-Sitter space relate to our intuition of 3D space (or 4D structure if you include time)?

I just ran into the AdS/CFT correspondence, as I am looking at various use-cases of hyperbolic tessellations, specifically related to the pentagrid and heptagrid as defined by Maurice Margenstern in ...
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Is there any proposed holographic/thermodynamic interpretation of gravitational time dilation?

In AdS/CFT and holography more generally, many proposals of various degrees of plausibility have been made linking apparently physical notions on the bulk side to more information-theoretic, ...
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AdS$_3$ Geodesics' Length in ambient space as done in "Aspects of Holographic Entanglement Entropy"

I have been following the mentioned paper ("Aspects of Holographic Entanglement Entropy" hep-th/0605073 by Shinsei Ryu and Tadashi Takayanagi), trying to get into AdS/CFT. In section 6.2 ...
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Why does no one add Einstein-Hilbert term to CFT in AdS/CFT?

As I work through AdS/CFT exercises, it struck me that there seemed no one doing the following. Suppose we have a holographic CFT. By some reeconstruction method, we can write CFT operators in terms ...
Bulldozer's user avatar
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Why $N\to \infty$ limit implies $g_s \to 0$ in holographic QCD?

One basic difficulty in QCD is that it does not contain a small dimensionless quantity that would allow for perturbative calculation of low-energy observables. A remarkable feature of holographic ...
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Why do we expect isometries of bulk side to be equivalent to symmetries of the CFT?

One can clearly see that the AdS bulk isometries form the $SO(d,2)$ symmetry of the $d$ dimensional CFT explicitly. Why does this occur: why don't the isometries of the spacetimes match up or the ...
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Why is empty AdS identified with CFT vacuum and what do excited states correspond to?

I have a few questions regarding the AdS/CFT dictionary regarding the state-state map. I have seen people identifying the empty AdS spacetime with a CFT vacuum. What do they mean by "empty" ...
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Unitarity in the 't Hooft limit

Consider a quantum gauge theory with a holographic dual at infinite $N$ and 't Hooft coupling, in which the gauge theory is described by classical (super)gravity. If I initialize the system in a pure ...
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Quantum corrections in Holography

AdS/CFT stablish that there is some kind of correspondence between the ${\cal N}=4$ SYM theory and strings in $AdS_5\times S^5$ space-time. I know, for instance that 1/2 BPS operators like Tr$(\phi_1^...
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de Sitter spacetime, spacetime without boundaries and holographic principle

One of the most intriguing aspects of black hole thermodynamics is that of holography or the holographic principle, namely, that the degrees of freedom of a putative theory of quantum gravity is ...
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Confusion regarding the Susskind-Uglum conjecture

I have a very basic confusion regarding entropies in holography. In AdS/CFT, the Susskind-Uglum conjecture states that the generalized entropy of a bulk region, given by $$S_{\text{gen}}(A) = \frac{\...
pseudo-goldstone's user avatar
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Does AdS/CFT correspondence apply to entire AdS space or those covered by Poincare patch?

I am getting confused as I study the AdS/CFT correspondence, so I ask this question. CFT is given on the conformal boundary of AdS, which can be derived from Poincare coordinate patch to AdS. Would ...
Neijal Kanderbalt's user avatar
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Phase shift in holographic one-point function

I have a simple question about the response of an operator one-point function to an external source $\propto e^{-i\omega t}$ in AdS/CFT. I consider a real scalar probe of mass $m$ in $AdS_{d+1}$ which ...
phonon's user avatar
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Reverse AdS/CFT correspondence?

$\text{AdS}_{n}/\text{CFT}_{n-1}$ correspondence provides a dictionary for one-to-one mapping observables in bulk gravity to boundary conformal field theories. However, does the reverse correspondence ...
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Penrose diagrams and Holographic Principle

What would the Penrose Diagram look like that represented a black hole (call it Black Hole-B), inside of a massive black hole (Black Hole-A), in our universe? and, as inside of the Penrose diagram for ...
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Definitions of Thermodynamics and Holography

There are many differences between the laws of thermodynamics and the laws of black hole thermodynamics (BHT): Zeroth Law: In thermodynamics, the Zeroth Law establishes the notion of thermal ...
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Is the Ryu-Takayanagi (RT) formula calculating coarse-grained or fine-grained entropy?

I think it is computing the fine-grained entropy. However, I am confused by the case that when there is a black hole in the bulk. The Ryu-Takayanagi surface may include the horizon of the black hole ...
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Holographic microscopy: how 3d structure informations are contained within interference pattern?

I am studying holographic miscroscopy and it seems to me that the possibility of constructing the three-dimensional image of an object by irradiating it from one side only is given by the '...
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Nature of spacetime in the holographic boundary

My understanding from popular science articles is that the boundary is a field theory that has no gravity and has one less spatial dimension than the bulk. However, I am not sure I understood this ...
Pato Galmarini's user avatar
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Resources for studying holography for someone with a long gap in physics

for the past 3 years I haven't been reading up on physics and I'd now like to get back into it by learning about holography. I have done courses on QFT and String theory but some concepts I've ...
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What do bulk Fourier modes look like in the boundary theory?

Suppose we have a bulk theory that has some holographic CFT dual at the boundary. Suppose we construct an operator that 'looks like' (whatever that needs to mean) a Fourier mode in the bulk ...
Panopticon's user avatar
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What does it mean for a quantum field theory to "live" on a manifold?

I was attending lectures om holography where the lecturer kept on mentioning that a QFT lives on a Cauchy slice. What does that mean? Is it such that each point of the slice is associated to a unique ...
Infinity540's user avatar
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Hawking Temperature for a hairy BTZ Black Hole

The metric of a hairy Black Hole is given by: $$ds^2 = \frac{L^2}{z^2}\biggl(-g(z) dt^2 + \frac{e^{2 A(z)}}{g(z)} dz^2 +d\varphi^2\biggr), $$ where $L$ is the AdS length taken to be $1$,$A(z)$ is the ...
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Naive questions on AdS/CFT dictionary and alternatives?

I'm starting to become curious about AdS/CFT since hearing that condensed matter theorists use it as a 'dictionary' to find gravity duals of things from condensed matter physics. How exactly does this ...
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Holographic self-energy for a scalar field in a slice of AdS

I am confused about a key step in Gherghetta's "TASI Lectures on a Holographic View of Beyond the Standard Model Physics" in the derivation of the holographic self-energy in the strongly ...
Henry Deith's user avatar
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Why is the holographic encoding from Bekenstein-Hawking entropy remarkable?

The holographic encoding interpretation from the Bekenstein-Hawking entropy is due to it scaling with the area $S_{BH} = A/4$ of the surface, rather than the volume $V$. While I am aware that most ...
Jahn Dorian's user avatar
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Research progress in the symmetries of flat space holography

I was studying the papers [$1$] Arjun Bagchi. The BMS/GCA correspondence [$2$] Duval, C., Gibbons, G. W., & Horvathy, P. A. (2014). Conformal carroll groups. Journal of Physics A: Mathematical ...
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Jackiw-Teitelboim (JT) gravity as a matrix integral

I am reading https://arxiv.org/abs/1903.11115 by Saad, Shenker and Stanford. They relate an (averaged) $n$-point function in a random double-scaled matrix model to a path integral genus expansion in ...
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In the context of the holographic principle, is the bulk-boundary correspondence due to entanglement?

According to the holographic principle, a "bulk" region of D dimensions corresponds to a "boundary" region of D-1 dimensions. In this context, the laws of physics of the bulk can ...
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Does the holographic principle allow realistically-sized universe simulation?

I was reading about the holographic principle and a question came up to my mind which I can't find an answer to. My understanding is that the holographic principle states that the description volume ...
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What is the fundamental reason why information is on the event horizon of a black hole?

I don't know the mathematics behind black holes and information theory but is there a simple explanation of why information is on the event horizon. Why can't it be elsewhere?
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Why are physicists surprised that the information of a black hole is proportional to its boundary?

I don't understand why physicists are surprised that the information of a black hole is proportional to its boundary. From a pure GR perspective, in my understanding, an observer outside a black hole ...
puzzleshark's user avatar
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In AdS/CFT, do we have Weyl-invariance or only conformal invariance?

The asymptotic symmetry group of $AdS_{d+1}$ is $SO(d,2)$, which just so happens to be the conformal group of $d$-dimensional Minkowski spacetime. Therefore the boundary dual, if it exists, has ...
nodumbquestions's user avatar
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Motivation of Holographic Exact Renormalisation Equation

I've recently been studying exact renormalisation alongside holographic renormalisation, and came across the following paper on the arXiv: https://arxiv.org/abs/hep-th/0001193. I'm trying to ...
notastringtheorist's user avatar
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What does the discovery of pressure of black holes imply for spacetime thermodynamics?

As far as I know AdS/CFT and spacetime thermodynamics was motivated by the Bekenstein-Hawking Entropy formula of black holes. Recently however it was discovered that black holes have a pressure as ...
eeqesri's user avatar
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Reading list for JT/SYK correspondence

I have been studying Gábor Sárosi's review of holographic duality between Jackiw-Teitelboim gravity and the Sachdev-Ye-Kitaev models for the last few days. This field has grown since the review came ...
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How many apparent horizons could the universe have?

I was reading a paper written by Nobel laureate George Smoot, Go with the Flow, Average Holographic Universe, which assumes the holographic principle as true and conjectures that our universe would be ...
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Local conformal group of the Euclidean plane and the (local) diffeomorphism group of locally Lorentzian 4-manifolds

Maybe this question is rather too general to mention, but I hope the community can help to make it more precise in case it's needed. The question is: if there's any link between the local conformal ...
Bastam Tajik's user avatar
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3 votes
1 answer
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Conceptually, why is the entropy of black hole related to Planck length?

I was watching a lecture on the holographic principle, and it presented the equation for the entropy of a black hole as $$S_{BH} = \frac{A}{4l_p^2}$$ My question is why, conceptually, the entropy of a ...
Relativisticcucumber's user avatar
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What is the relation between the free energy and the action? More generally, what is the relation between Thermodynamics and Lagrangian Mechanics?

My question stems from the sentence said by my professor "The action is the free energy" which I don't understand. Thinking that probably I'm missing some key concepts, I'd like to know: ...
Mauro Giliberti's user avatar
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How is the Virasoro symmetry realised on $AdS_3$?

In the context of the Holographic correspondence, $AdS_{n}/CFT_{n-1}$, it is often cited as a "confirmation" that the two symmetry groups of the theories correspond. Indeed, in dimensions $n&...
Frotaur's user avatar
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Can the holographic surface of our universe be located at the cosmic horizon?

I just listened to a Susskind's talk at Stanford, where, as an answer to a question, he said that may be the surface that contains the information to describe our 3D universe might be located at the ...
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1 vote
1 answer
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Does the holographic principle imply a finite universe?

Please correct me if I am wrong here, but it seems that the holographic principle sets an upper entropy bound that scales quadratically with the radius of the sphere under consideration, while the ...
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Boundary condition from extremization

I have an AdS Schwarzschild blackhole spacetime where the metric is given by, $$ds^2 = \frac{1}{z^2} \left( -f(z) dt^2 + \frac{dz^2}{f(z)} + dx^2 \right) \tag{1}\label{1}$$ There is a plane embedded ...
mathemania's user avatar
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1 answer
569 views

Is the Quantum Gravity mystery already solved by Susskind? [closed]

Very recently, Leonard Susskind presented a lecture presenting his proposal of Quantum Mechanics = Gravity (equality means duality). Quantum Origins of Gravity Is this really the end of Quantum ...
Bastam Tajik's user avatar
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5 votes
1 answer
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Relation between the condensation gap and the critical temperature in superconductors/holographic superconductors

In some articles about holographic superconductors, it is written that when the condensation gap increases, the critical temperature decreases. For example, here: https://link.springer.com/article/10....
Kheeyal's user avatar
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On the properties of a projection map from points in the bulk to qubits on the boundary

Note: I have completely re-edited my post, so as to make it much clearer. I apologize for the previous version of this post, which I had written rather fast. Let $H^3$ denote hyperbolic $3$-space and ...
Malkoun's user avatar
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1 answer
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AdS-CFT correspondance from 1D to 4D

From what I understand the AdS-CFT correspondence states that the bulk dynamics of a $n$-dimensional gravitational theory are encoded in the degrees of freedom of its dual CFT in the $(n-1)$ ...
George Fanaras's user avatar
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1 answer
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Computing the DBI action on $S^5$

I've been looking at this paper (arXiv: 1103.4079). On page 7, from the metric of the giant gravtiton on $AdS_5 \times S^5$, $$ds^2 = -\cosh^2\rho \, dt^2 + d\rho^2 + \sinh^2 \rho \, d\tilde \Omega_3^...
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