## Why Our Universe is Not a Hologram

Article Updated: 23 Dec , 2015

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Editor’s note: This article was originally published by Brian Koberlein on G+, and it is republished here with the author’s permission.

There’s a web post from the Nature website going around entitled “Simulations back up theory that Universe is a hologram.” It’s an interesting concept, but suffice it to say, the universe is not a hologram, certainly not in the way people think of holograms. So what is this “holographic universe” thing?

It all has to do with string theory. Although there currently isn’t any experimental evidence to support string theory, and some evidence pointing against it, it still garners a great deal of attention because of its perceived theoretical potential. One of the theoretical challenges of string theory is that it requires all these higher dimensions, which makes it difficult to work with.

In 1993, Gerard t’Hooft proposed what is now known as the holographic principle, which argued that the information contained within a region of space can be determined by the information at the surface that contains it. Mathematically, the space can be represented as a hologram of the surface that contains it.

That idea is not as wild as it sounds. For example, suppose there is a road 10 miles long, and its is “contained” by a start line and a finish line. Suppose the speed limit on this road is 60 mph, and I want to determine if a car has been speeding. One way I could do this is to watch a car the whole length of the road, measuring its speed the whole time. But another way is to simply measure when a car crosses the start line and finish line. At a speed of 60 mph, a car travels a mile a minute, so if the time between start and finish is less than 10 minutes, I know the car was speeding.

A visualization of strings. Image credit: R. Dijkgraaf.

The holographic principle applies that idea to string theory. Just as its much easier to measure the start and finish times than constantly measure the speed of the car, it is much easier to do physics on the surface hologram than it is to do physics in the whole volume. The idea really took off when Juan Martín Maldacena derived what is known as the AdS/CFT correspondence (an arxiv version of his paper is here ), which uses the holographic principle to connect the strings of particle physics string theory with the geometry of general relativity.

While Maldacena made a compelling argument, it was a conjecture, not a formal proof. So there has been a lot of theoretical work trying to find such a proof. Now, two papers have come out (here and here) demonstrating that the conjecture works for a particular theoretical case. Of course the situation they examined was for a hypothetical universe, not a universe like ours. So this new work is really a mathematical test that proves the AdS/CFT correspondence for a particular situation.

From this you get a headline implying that we live in a hologram. On twitter, Ethan Siegel proposed a more sensible headline: “Important idea of string theory shown not to be mathematically inconsistent in one particular way”.

Of course that would probably get less attention.

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Anonymous
December 13, 2013 1:50 PM

I must have missed the part where you explained why the Universe isn’t a hologram…?

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?œarar Ó Murchadh
December 13, 2013 2:23 PM

its right here.

” It’s an interesting concept, but suffice it to say, the universe is not a hologram, certainly not in the way people think of holograms. “

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Criminoboy
December 13, 2013 9:37 PM

That’s a statement – not an explanation.

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?œarar Ó Murchadh
December 14, 2013 3:28 PM

No, that’s a quote of a statement of which is not my own, unlike this statement of me explaining something, like this very statement explaining statements.

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Unsooper
December 14, 2013 3:03 PM

How about this? I see you because photons fire off cells in my retina. You could just be a hologram to me (or not) because someone could measure my nerve response and not tell the difference by measuring cause and effect in me….but since that doesn’t measure the actual “you” at all it turns out the theory is weak.

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Nimrod0
December 13, 2013 2:24 PM

Because most people read “hologram” and think “fake,” when here it is a technical word meaning something else, namely information flux crossing a boundary into a volume.

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psychman33
December 14, 2013 2:12 AM

It’s actually never explicitly stated in an idiot proof kind of way. But the gist is that it’s a theoretical concept applied to another theoretical concept that is not necessarily an accurate representation of our universe, just a model of a possible hypothetical universe. So you have a theoretical concept on top of another theoretical concept that shows the possible existence of a hypothetical. That’s pretty shaky external validity, no?

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hjhjh
December 14, 2013 2:31 AM

But his assertion is “our universe is NOT a hologram” not “it’s not known yet whether or not our own particular universe is a hologram.” Yet he fails to prove his case. I guess a more modest headline would “probably get less attention.”

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Criminoboy
December 14, 2013 3:17 AM
Well – if that is the point he forgot to make, it would make sense if this study stood on it’s own, but it doesn’t. It is one more very compelling piece of evidence, which can be stacked onto the growing pile of evidence which has grown awfully weighty over the past decades. This evidence isn’t just theoretical, but physical as well. We’ve very likely already measured the quantum flux of the plank length in Germany via the GEO , and we’re probably very close to definitively measuring it at Fermilab: http://www.gizmag.com/fermilab-holometer-examines-spacetime/16829/ The author of this article states that the universe is not a hologram in a way which purports to indicate that this experiment doesn’t actually attempt… Read more »
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psychman33
December 14, 2013 3:28 AM
“It all has to do with string theory. Although there currently isn’t any experimental evidence to support string theory, and some evidence pointing against it, it still garners a great deal of attention because of its perceived theoretical potential.” “While Maldacena made a compelling argument, it was a conjecture, not a formal proof. So there has been a lot of theoretical work trying to find such a proof. Now, two papers have come out (here and here) demonstrating that the conjecture works for a particular theoretical case. Of course the situation they examined was for a hypothetical universe, not a universe like ours. So this new work is really a mathematical test that proves the AdS/CFT correspondence for… Read more »
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Criminoboy
December 14, 2013 3:58 AM

You’re right – I missed your point.

I’m reactive to the author’s definitive statement that “the universe is not a hologram” when the weight of the evidence seems to be leaning so heavily in that direction. The Nature article clearly states the study represents, “if not an actual proof, at least compelling evidence that Maldacena’s conjecture is true.” The study doesn’t exist in a vacuum – and the implications of the combined evidence don’t appear to warrant the blanket dismissal this article represents.

Thanks for the clarification.

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Andrei Patrascu
December 19, 2013 10:23 PM
The article just verifies something known in a model where we know that something exists and works. So, indeed, it is not a proof and no evidence for anything related to reality. There are in fact lots of evidence that the universe is NOT a hologram in the sense understood by string theorists. Area law violations are everywhere in nature and in fact the entropic area laws appear in any systems where we choose not to make some kind of measurements and not to ask some questions. There is no justification whatsoever for these choices of ours. Also, the statement about string theory is correct. It is more than obvious that string theory and the holographic principle are… Read more »
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psychman33
December 14, 2013 3:47 AM
Mathematics is formal logic following from foundational axioms. Logical consistency is not a valid inference for actuality of the findings. Just as purely rational arguments cannot establish validity to the world of experience, so these papers cannot be necessarily applied to the actual universe we inhabit. He’s saying that what they have established is true enough in a useful model establishing the plausibility of the scenario. But it’s overstating the findings to say that it applies to this universe. He’s not challenging the findings so much as the external validity of these findings. The media pickup of these papers have, as media so often does, overstated the valid inferences that follow from the character of these studies. In… Read more »
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Andrei Patrascu
December 19, 2013 9:59 PM
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Andrei Patrascu
December 19, 2013 10:01 PM

also, the main reason DMRG fails for D>1 is a good reason too…

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A guy
December 24, 2013 4:43 AM

Your query is valid; I don’t think he explains why the Universe is not a hologram. Instead, he’s just asserting that the math behind a hypothetical universe being a hologram is accurate, which doesn’t necessarily prove that our universe is or isn’t. It’s like proving that testicles can be made of metal, but doesn’t really prove that yours are. For that we’ll have to kick you in the nuts and find out.

… I think you get my analogy, f’d up as it is.

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JOSHUA VEGA HAWKINS
December 13, 2013 2:17 PM

Reel them in with the headline.

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David McElroy
December 13, 2013 2:17 PM

“And God said, Let there be light: and there was light,” Genesis 1:3 states. Light was the first and most basic element created, and science seems to document that the whole universe is a tapestry woven of photons. Hence, an intelligently designed holographic universe.

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Skeettz
December 13, 2013 2:33 PM
First off I want to point out that all though Gerard t’Hooft was the first to publish a paper on this idea, it didn’t get much attention. It wasn’t until Leonard Susskind published his paper “The World As a Hologram” that the idea really started taking hold among theoretical physicist. In 1993 the mathematics of the idea were not worked out and it was Leonard Susskind who was giving lectures upon lectures to try and get more people working on the idea. t’Hooft saw the idea in a little different light and didn’t like the fact that sting theory was involved. Susskind’s said once “black holes really do have hair” meaning parts of a tangled up mess of… Read more »
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Criminoboy
December 13, 2013 8:33 PM
Thank you for the great post. I’m not a physicist by any stretch, but have been fascinated by the developments of the Holographic theory over the past few years, and this article almost seems to be referring to a different topic altogether. I get the impression that Brian isn’t a big fan of String Theory? Your description of the “2 dimensional boundary” is very much what I have managed to grasp from what I’ve read. I’m aware that this likely only represents the best incomplete description to provide a layman – but this article doesn’t cover any of the main concepts under discussion, as you have. It also seems to fail to recognize that the Fermilab Holometer is… Read more »
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Brian Joe Wells
December 13, 2013 3:15 PM

the only thing real is Squirrel Girl…..

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Gary Denton
December 13, 2013 3:52 PM

This article appears to so wrong it is not be in the same classroom of why physicists are excited.

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Skeettz
December 13, 2013 5:12 PM

lmao all I can say… because the bible has so many facts imbeded in it along with all its contradictions. Intelligent design is an illusion.

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daniel_rey_m
December 13, 2013 5:33 PM
Alfonso Caycedo, M.D., the developer of sophrology, came back from a trip to the Far East having confirmed that the mind can achieve the dematerialization of the body. In the Tibetan monasteries some monks go into their cells and never come out again. All that remains is the robe, the shoes, the hair and the fingernails, which shows that only keratin is impervious to whatever brings about the dematerialization. The source for this information is the travelogue he wrote after the voyage. It also shows that what we see is an illusion sustained by the mind, is no more substantial than a hologram and can be turned off like a hologram if that’s what one wishes to do.
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Aleister Gates
December 13, 2013 5:50 PM

dolt

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truthseeker
December 14, 2013 7:30 PM

It aint easy, but something immaterial affected the “Robe of Turin”.

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anotherview2
December 14, 2013 12:17 PM

Ha, ha, Dreamworks abound in the ozone layer.

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GMcDowell
December 13, 2013 6:25 PM

String theory is nothing but fantastical mathematics. It does not in any way, shape or form describe the universe we inhabit. It is a real disservice to continue writing articles about a discredited mathematical theory as if it has merit in astrophysics when it clearly does not. Please let this be the final posting about ST.

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GMcDowell
December 13, 2013 6:27 PM

If you knew anything about the early universe, you’d know that:
1. There was no light.
2. There never was a deity other than the mythical kind.
Do grow up.

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Sal
December 13, 2013 7:37 PM

Unless God lives in a different universe and our universe is his “fish tank”?

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truthseeker
December 14, 2013 7:26 PM

Of course! God is the being that changes the water!

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jefferis
December 14, 2013 7:55 AM

You have insufficient evidence for assertion 2, and you misunderstand the sequence of #1. Darkness was first: “In the beginning… the universe was without form and void, and darkness was upon the face of the deep” (Gen 1:1,2) and then there was a Big Bag (Light) v. 3.

Member
December 14, 2013 12:00 AM

You know there is a very wise saying you’d do well to remember.

“Those who attempt to find answers to matters of science with religion
as well as
Those who attempt to answer matters of faith with science.
TRULY UNDERSTAND NEITHER

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A.R
December 14, 2013 3:56 AM

wait…so i do exist or I don’t exist? This is so confusing…I’m going to go eat a burrito.

Member
December 16, 2013 5:32 PM

It’s weird that someone should mention boorreetoes here. Last year one of them vanished from my plate as I read a magazine. I looked up and it wasn’t there anymore. This happened again about three weeks later. It’s additional proof for the Hologram Universe Theory. Please see the blog at [Blog promotion not permitted – buy advertising!] and leave a comment.

Guest
December 14, 2013 8:46 AM
Dr Koberlein, I don’t understand where the obsession of people like you to write about topics you have clearly no clue about comes from. The Universe *is* a hologram, quite literally. It is not made of the same “films” as the holograms on our credit cards but it follows the same principles: the actual physics may be described in terms of fields on a manifold which has one dimension less than the final “product” – the location of the objects in the new, emergent, holographic dimension is encoded in the wavelength of the interference patterns. This is true both for the real-world holograms on credit cards as well as the holograms in quantum gravity. Every consistent theory of… Read more »
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Beth Kuda
December 14, 2013 9:11 AM

So wait… People took the word “holographic” in this context to mean the sci-fi version of an object projected in 3D? … Sometimes I wonder how we ever managed to walk upright to begin with.

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Jihm
December 14, 2013 10:04 AM

In my opinion, the only sort of non-infinite reality possible is a simulation.

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stig781
December 21, 2013 5:07 PM

That’s an artificial technological concept.

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anotherview2
December 14, 2013 11:12 AM

Thank you for putting this twist of theoretical physics (string theory) in an understandable context.

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David Gillies
December 14, 2013 3:06 PM

The idea of operations on a manifold being equivalent to operations on a contour embedded in that manifold is hardly new. That’s Stokes’s Theorem, and it’s first year undergraduate physics. What I’d like to know is whether Maldacena’s work is a restatement, an amplification or merely analogous to Stokes.

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magnus.nyborg
December 14, 2013 7:30 PM

Yeah, but then god supposedly introduced the talking snake, and that’s where one should realise the idiocy…

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Mark_2674
December 14, 2013 9:08 PM

I know I read that information about a black hole is derivable strictly from its surface (google it). The point is that this idea has apparently been applied successfully in a number of areas.

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Mark_2674
December 14, 2013 10:19 PM

Does a hologram universe imply that all information about a person, there internal physiology, life history, etc, can be determined by examining their external surface?