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Study reveals substantial evidence of holographic universe (sciencebulletin.org)
313 points by upen on Jan 30, 2017 | hide | past | web | favorite | 189 comments



Possibly dumb question, but I know my niece is going to ask me about this, and I'd like to be able to give her a solid response: does this mean that most distances within our universe are illusory? If not, why not?

To expand on that thought a little bit, with a hologram, the projected object is an illusion, and can be made to appear to move at arbitrary speed by e.g. rotating the projection apparatus. On a larger scale, it's possible to create the illusion of FTL movement by e.g. rapidly rotating a laser projector in space and then traveling a long distance from it, so that at a certain distance from the source, it appears that there is a projection from the source which is rotating faster than light.

If this theory models the universe as a 3D (or more) projection from a 2D surface, why is it not possible to cause objects within our perceived 3D+ universe to appear to move faster than light by causing some sort of change to the 2D surface itself? I assume there is a reason this is not possible within the bounds of this theory, but I have no idea what that reason might be.


Yes, but it's not the case that everything is equidistant. Allow me to illustrate with a simplified example from lower dimensions.

(Warning: pseudoscientific bullshit ahead)

Picture a transparent sphere, covered in tiny dots. Imagine that you live on one of these dots and the others are stars. Now, mark 'your' dot and look around on the sphere to find the dot that is farthest away, on the opposite side. If the internal radius of this sphere is 1 unit, then the distance to that dot (traveling on the surface of the sphere) is pi units. Imagine yourself in Edwin abbott's Flatland, but thanks to relativity you know this flat universe to be finite and bounded, such that if you set out in any direction in a straight line you will eventually arrive back at your starting point.

Now, let's designate that point opposite you on the sphere as the Maximally Distant Star. There's no doubt, no matter what route you take along the surface of the sphere, this is as far as you can go before you begin coming back, if that makes sense. But suppose you were able to transit across the interior of the sphere instead of across the surface. It's still the farther point from you, but by transiting by volume instead of on the surface the distance is only 2 units, or 63% as far as it appears to the surface-dwellers.

Of course, this realization is of little help in figuring out how you as a Flatlander can access that theoretical 'volume' so as to shorten your transition time. If you could, you'd seem to disappear at your existing location (most likely by shrinking down to a point, or possibly seeming to turn inside out, or both) and then reappear at your destination, assuming you hadn't been eaten by the great old ones said to inhabit that forbidden space by famous horror author J. Q. Likecraft.


This makes sense, but seems to be an answer to a different question about the curvature of spacetime. How does it relate to the universe being a hologram?


It doesnt. The hologram is a metaphore. Once upon a time our 3/4 dimension world was encoded upon a world with fewer dimensions LIKE a 2d hologram contains the info of a 3d image.

This world didnt last very long. Under our concept of time it happened long ago, but we can see evidence of it smeared across the sky in the cosmic microwave background. (A 2d image that should look the same no matter where you stand in our 3d space.)


Only indirectly (I did warn you I was gonna bullshit a bit). One obvious way would be in a spherical projection onto a flat surface, but that makes it harder to explain the basis of the curvature first.

I apologize for being so vague; I'm trying to develop something more solid related to this idea, but I'm at that in-between stage of not being ready to properly articulate it yet.


Howard Phillips Lovecraft I presume?


Distances are "illusory" to some extent anyway. On a large scale, relativity makes both time and space dependent somewhat on other factors. On a small scale, quantum mechanics similarly de-absolutizes position (space) and momentum.

Space and time as absolutes appear to be a construct, a consequence of us being highly complex neural networks trained at a specific scale of the Universe - the "human scale" - as beings about 1 ... 2 meters in size. Absolute time and absolute space appear to be very real on this scale. But as soon as you leave this order of magnitude, and climb either up or down on the scale of things, this turns out to be mere provinciality.


Up or down several dozen orders of magnitude. Time and space exist for the cells in our bodies, and for mountains, moons and most stars. Time and space only break down substantially for things smaller than molicules or large enough to twist spacetime back in itself (black holes). A mouse is no further away from the moon than a dog or elephant.


Time and space does not exist for a mountain.

Time and space are first and foremost concepts (ideas, opinions, "facts")

Have you tried asking a mountain whether it ascribes the state "exist" to the concepts of time and space?

It is true that time and space exists for humans thinking about the mountain however.


> Time and space does not exist for a mountain.

Time exists for the mountain. The mountain moves through time and is effected by time. The mountain is incapable of perceiving time. Neither can bacteria perceive dimensions, but they are still controlled by them.


No it does not

A mountain is a part of spacetime. But it does not "exist" for the mountain.

Certainly the mountain is affected by the environment and can be modelled with the spacetime concepts. But the mountain does not perceive anything, and therefore cannot compute isExist (spacetime)


I'm willing to call bullshit on this. Space and time may be constructs but they are "helpful" constructs in that they model specific forces which apply to both us and the mountain. I perceive the waste of this body over time: the mountain is subject to these same wastes and transformations as this body.


> Up or down several dozen orders of magnitude.

I agree.


I don't think so. The holographic universe a "projection" in the sense that the information can be thought of as living on the boundary of a given space, with the maximum entropy / information contained therein proportional to the boundary's surface area (on a quantum level, a bit is a measurement of area). But this isn't super shocking if you're aware of the idea of "light bubbles" (the generalisation to three dimensions of a light cone) which already describe the limits of how information in a region of space can propagate.

Distance was already an illusion, insofar as it represents a non-unique projection of a spacetime using purely relativistic techniques. :) But the speed of light isn't going to be got around by any of these models. If anything, the models will explain this limit better.

POSTSCRIPT:

I recommend the Hammock Physicist as a random physicist who can explain concepts like this at just the right level of detail for the HN audience. http://www.science20.com/hammock_physicist


The top article on that site at the moment is about the "Jewish elite". WTF?

http://www.science20.com/sascha_vongehr/scientists_for_donal...


Kind of terrifying since I just read this article on the targeting of specific groups: https://medium.com/@yonatanzunger/what-things-going-wrong-ca...


Interesting. Why does that author claim to have knowledge or expertise? I looked at his bio but didn't learn much about him.


It's clearly a right-wing site.

Or at least they seem to rant against "leftist" scientists. http://www.science20.com/kevin_m_folta/the_scicomm_challenge...


I wouldn't think being "right wing" would be sufficient to explain using the phrase "jewish elite".

Like, can we not treat "the people who say things like 'jewish elite' " and "people who are right wing" as being the same group?

I mean, I'm not saying they don't have an overlap ( It is probably true that P(a person is right wing | they say stuff about "the jewish elite") > P(the person is right wing) ),

but I'm concerned about the social incentives that might be created/contributed-to if they are treated as if they are the same.


Ahh, you're completely right, it's a lazy phrasing.


> It's clearly a right-wing site.

... It's clearly a collaborative site with hundreds of authors, at least two of whom are right-wing authors, who have presumably got to the top being controversial and attracting attention from outside the normally quiescent community of readers talking about entropic gravity, thus convincing the algorithms their content is worth showcasing.

HERETICS, THE LOT OF THEM! BURN THE DATA CENTER WITH FIRE!!!


Is this the real-life equivalent to Plato's Allegory of the Cave [1]?

I wonder if books like Zelazny's Amber series will seem, in retrospect, more insightful.

[1] https://en.wikipedia.org/wiki/Allegory_of_the_Cave


I thought of "Shadow" upon reading this. Delightful series. Fun romp.


Perhaps a bit of a tangent, but another way I have always perceived relative distances measurements is with the following analogy:

You are awake, walking around a basketball gymnasium, it's 100x100x100ft. A nice, large room. All other details preserved as well. Surely, our little brains can't contain a 100x100x100ft gymnasium; our little heads would explode trying to fit something so large into it. Yet, when we dream, we are perfectly capable of revisiting this large room in our mind, full spatial properties preserved.

While there are many encoding strategies, looking at how the brain encodes information (or a more simplistic neural network), this gives, in my opinion, a good intuition as to how distance and spatial properties can both differ and relate between two "universes".

You can also observe that our final "view" of the gymnasium is just the surface of the complex underlying thought-structure of the brain. We very much, on a daily basis, only see the surface of what is a very very complex process going on inside the brain.

Perhaps, one may even call that a projection.


There is just so much more to discuss on this subject, including the intricacies of how all events are stored in the brain with cross-connections/relations to other events. Basically, every memory-dimension (time, temperature, happiness, anger, feelings) are all stored in nice gradients with connections to other memories. i.e. The only thing making you think that some past event, yields to some "next" event, is a series of synaptic connections, saying it does. I think the deeper you dig, the more you see how things breakdown from this simple linear view of events happening in your day-to-day life. I'll end here for now at risk of being vague unless asked for further clarity. :)


This reminds me of Kurzweil's explanation of dreaming, as offered in "How to create a mind" book. He claims that during dreaming we experience random, uncoordinated activation of synaptic links and some small portion is recorded in memories. It is only when we recall our dreams that we infuse meaning into them, building a structured and sequential narrative around random stimulus so that our mind can make sense of these memories.


This is falsified by people who have had interactions with waking people while asleep, conducting conversations and interactions, even if nonsensical. So there is online processing during dreams, not just a "ghost" memory left behind afterwards.


Not a dumb question at all. Questions like these are the very heart of physics, actually.


My opinion is "no", because causality still exists on a 2D surface. The speed of causality will limit information from entangling with other information faster than a given rate in an offset of X or Y - if there was no limit, there'd be an infinite amount of calculations occurring on the surface in an infinitely short amount of time. You can sorta imagine it as the cells in an area of Life must be "recalculated" to fill in when you left or arrived. That certainly might translates into a different type of causality here, as it does seem that this reality is pretty intent on limiting the ability to change things here instantly.

Which reminds me of Feynman's theory that there was only one Electron and it was everywhere in the universe all at once over an infinitely long period of time, and could even travel in time if it had to.


> If this theory models the universe as a 3D (or more) projection from a 2D surface

Further, would such a projection suggest a possible mechanism for entangled particles to interact at distance (e.g. the particles are separated in 3D-space, but are co-located in 2D-space)?


No. Entangled particles don't interact at a distance.


> [...] why is it not possible to cause objects within our perceived

The universe is currently not in the holographic phase. That is thought-provoking, though. Let's assume that this is plausible. During the holographic phase, the speed limit wouldn't apply. There are a few interesting theories that require FTL during the big bang.

What I find interesting is that the universe went through two very distinct phases and we have two distinct physical theories.


Calling it "holographic" was probably a bad idea because it generally makes people think about Star Trek. You're not quite as far off when you think about lasers shining through a photograph of an interference pattern in order to reproduce a light field that a human observer will perceive as a 3D object.

If you look a that photograph in normal light it just looks like a lot of black and white lines and blotches smeared out over the surface instead of the original object that was photographed. In a holographic model of the laws of physics, the entire content of the universe is encoded somehow onto a 2D surface. If you could somehow see that surface, it would not be obvious that it encoded anything in particular. Where the analogy falls down is that there is no laser that projects a 3D image from this surface. There's just a set of 2D laws operating on the 2D information. To anyone on the "inside", as it were, the universe still appears to be fully 3D with 3D laws of physics.


IANAPhysicist, but I think T-duality in String Theory [1] also makes distances "illusory".

"If string theory is a correct theory of Nature, then this implies that on some deep level, the separation between large vs. small distance scales in physics is not a fixed separation but a fluid one, dependent upon the type of probe we use to measure distance, and how we count the states of the probe." [2]

Brian Greene also explains why in an accessible way in the Chapter 10 of The Elegant Universe [3], which I recommend.

[1] https://en.wikipedia.org/wiki/T-duality

[2] http://www.superstringtheory.com/basics/basic6a.html

[3] https://en.wikipedia.org/wiki/The_Elegant_Universe


Can anyone illuminate what relationship, if any, this has to anti-deSitter space? Both seem to deal with lower-to-higher 'projections' of spacetime but I've struggled to find a good intro to AdS.


I have nothing to add other than I think it's awesome your niece might ask you about this.


I've recently been thinking on how our human definition of intelligence might relate to holographic principles, particularly in regards to information theory.

We are small creatures, but our networks -- our brains and societies -- represent the most complex information-encoding geometries we've yet seen in the universe.

And I see the way that our curiosity reaches upward in scale, documenting the far corners and folds of the universe; and deeper, interrogating the tiny subatomic spaces; and forward and back, building models of the future and past of this point in time.

And we capture this knowledge and bring it into our tiny space, information encoded in structures along the skin of this rock floating in space.

And I wonder if that's not holographic in some way: That insatiable drive to compress information from massive scales of space and time into the tiniest of spaces...

But of course, this is just armchair philosophizing ;)


Haha, beautifully put, but I often wonder the opposite. What if our capacity to perceive and think is so limited and narrow that most of the underlying workings of reality are completely missed by us? The what if being, we are not so special as we think. The way an ant colony will bustle full of self-import and purpose, blissfully unaware of the giant people passing by. And the people pay it no mind, because they can't interact meaningfully with the ant colony, so while one is aware of the other and far more about the world, the reverse isn't true.


Mix those thoughts with a healthy does of "human values don't necessarily have any relation to alien values, which may be just as incomprehensible to humanity as the true nature of the universe" and you've basically got the Cosmic Horror fiction genre.


and here I was trying to avoid an existential crisis today. There that goes.


Could be a dimensional thing too, what if you're like an exhibit in someone's living room like a hologram and you just live your life for someone's amusement. You'd never know but can you prove that it's happening?


Reminds me of The Thirteenth Floor.


Oh I like that movie, man haven't seen that in a while. I don't know, what makes something "real" or "more genuine"? I heard this podcast that mentioned this same concept regarding your brain acting like a computer perceiving sound as binary input through the little hairs in your ears... I don't know. What's real is this fear I feel from debt collectors haha.


That sounds a little like "The Principle of Mediocrity" (https://en.wikipedia.org/wiki/Mediocrity_principle)

If so, think you're selling humans a bit short. Our capacity isn't really all that limited. As long as we are able to continuously apply new information to gain better insights into reality, we will improve. Maybe we are woefully behind other some other beings out there, but that doesn't mean we'll never get there. Our capacity for exceeding our physical limitations (ex, we can detect neutrinos despite having no ways to see them through evolutionary abilities) and create new physical realities (the coldest known temperature measured is not somewhere else in the universe, it's in a physicist's lab) shows that we are still on a path towards understanding so much more than we do today.


I think that the information-mania you describe is a quirk of a certain personality type, not a basic human phenomenon. Information is certainly important to humans, but this omnivorous "insatiable drive" is not, I think, foundationally human, nor universal, nor even necessarily entirely present in the personality type that believes it posses such a drive.


I dunno. Every time I talk to a child, an "insatiable drive" for information is exactly how I would describe their state of being. Picking up speech, social norms, fine motor control, reading, writing, learning to identify physical danger and risk, and even the speed and fluidity I see when children learn to use technology (especially compared to some adults) makes me think that insatiable information gathering (and trying to apply that information and get new pieces) is extremely foundational. The drive and necessity to do so doesn't necessarily remain as intense as we mature, but that doesn't mean the capacity to do so isn't still there for folks who wish to apply it.


Unfortunately more true than I wish it were.


The conceit that the obsessive pursuit of information is necessarily a good is also a quirk of that personality type.


Why is it conceited to say that the a culture of relentless information pursuit has been an objectively good thing for humanity?

I guess I'm not sure what "obsessive pursuit of information" means in this case. Is it continuing to seek better explanations even when current ones serve a purpose adequately (ie, the principle of fallibility)? Is it that once new explanations are available people we seek to apply those explanations to other domains and create further information?

I'd argue that both of those examples are positive practices that have resulted in better quality information and expanded valuable applications of that information.

I cannot see the progress that humans have made since the scientific revolution and write those improvements off as non-objectively positive things. Earth is not naturally hospitable to our form of life, and our ancestors suffered through extremely short, brutal, and unpleasant lives due to that. It is only through the pursuit of information (obsessive pursuit even, in the sense that we needed a large amount of information that is both reliable and expandable to apply meaningfully) that most humans live lives where we don't die from things like starvation, exposure to the elements, treatable diseases and so forth. New problems have certainly been introduced by the application of gained knowledge, but those problems will never be solved by not pursuing more (and better) answers.

Less information is never better than more information, and societies which advocate most liberally for the pursuit of information have reliably produced better conditions for their people than those which do not.


I'm not so sure that our human brains and human societies are the most complex information encoding geometries in the 'verse. The brain of an elephant's trunk motor control cortex is pretty amazing, and they have a very complicated social system too. Ants also outweigh humans in terms of total biomass, let alone number of ants, and their eusocial system of 'governance' inside of a colony and between colonies is barely grasped as it stands. Do these creatures have a sense of 'curiosity'? Elephants are really close to maybe having it, but as for ants? Who can tell? Does that mean that they cannot build models of the future too, perhaps in ways we will not understand for millennia?

I think it's just evolution, nothing more, but that is not to say that evolution as a very simple principle has not made astounding 'discoveries'. We evolve, elephants evolve, ants evolve, and in that bloody and hungry process, beautiful things of incredible complexity emerge all over the globe.


If you haven't read it already, I suspect you would greatly enjoy "The Beginning of Infinity" by David Deutsch (a quantum computation-focused physicist). It's a surprisingly optimistic take humanity's nearly-unlimited potential (or so he posits) for discovery and creation, and a great companion for any armchair philosophizer.

I suspect that many of the replies to this comment who cynically cite variations of "the principle of mediocrity" would also do well to read it.

He makes the point that the single coldest place in the known universe is not anywhere in the depths of space (which is gets down to about 3 kelvin), it's in a lab designed by humans and used for quantum mechanics research (200 nano kelvin).

Our capacity for information gathering and creativity has allowed us to create physical realities that cannot otherwise exist outside the influence of intelligent beings. Incredible to think about.


> And we capture this knowledge and bring it into our tiny space, information encoded in structures along the skin of this rock floating in space.

Hey, this is imaginative, even if it's armchair philosophy. Seems like you are thinking that the holography principle is self-similar at many scales.


Your talking poetically, or metaphorically, not scientifically I assume?


I'd say philosophically, which is the root of science. The observation, while perhaps may not be provable, makes perfect sense to start a series of long and interesting discussions.


At one time yes, but present day most don't consider philosophy a science. https://opinionator.blogs.nytimes.com/2012/04/05/philosophy-...


First, here is a link that is not hidden behind a paywall: https://arxiv.org/pdf/1607.04878v2.pdf

> there is substantial evidence supporting a holographic explanation of the universe—in fact, as much as there is for the traditional explanation of these irregularities using the theory of cosmic inflation.

This is a bit misleading, especially the phrase "substantial evidence". I bet that the authors of the paper would not have used this phrasing. From the paper:

> We emphasise that the application of holography to cosmology is conjectural, the theoretical validity of such dualities is still open and different authors approach the topic in different ways.

Essentially, their paper shows that a holographic model cannot be ruled out simply by comparing the predictions it makes for the CMB to observation. It also gives some intuition for why a holographic model might make sense - at sufficiently early times in the Universe quantum and gravitational effects begin to coincide, and in other contexts people have modeled quantum gravity using "a quantum field theory with no gravity in one dimension less". The paper finds, however, that there is no empirical case to be made for discarding the standard model of inflation:

> We see that the difference between evidence for [the standard model] and HC predictions is insignifcant, with marginal preference for HC, depending on the choice of priors.


Question, from someone who does not understand the Holographic universe idea:

If 'true', is the holographic universe 'merely' a mathematical tool that helps us solve problems, or is it a description of an objective reality, and the universe is 'really' a 2D surface, and our 3D perception is somehow illusory?

I understand this is partly a philosophy of science question, but would be interested to hear an expert opinion ...


Until and unleas.a theory is falsified and revealed to be an incomplete model, there is no way to differentiate the "mathematical tool" from the "underlying reality" case, since any theory that works without qualification is, by definition, a model which is not detectably distinguishable from being the underlying reality.


So is holographic universe theory expected to work without qualification (thus being indistinguishable), or is it more of a temporary patch that nobody believes is correct, but works better for one area, and worse for others?

Newton's model of gravity works well enough for approximation at human scales, but is flawed enough that you don't use it for astrophysics or microscopic realms.


No model accurately represents reality. I think people have this idea that if I have 2 different theories that predict exactly the same thing, that one of them is right and another is wrong. This is exacerbated by a misunderstanding with Occam's razor. It is popular to believe that given those 2 theories, the simpler one is correct. This is not necessarily the case. The simpler one is simpler and therefore a better model to use (being simpler ;-) ).

If it walks like a duck and quacks like a duck, is it a duck? What if it's really something indistinguishable from a duck, but not actually a duck? What does that even mean? Our concept of "duck" is inextricably connected to our perception of it. A "duck" does not exist in the way we envision it, if we do not envision it.

So backing up to your question again, does this theory (or any other theory) explain everything about the universe, or is it more of a temporary patch that nobody believes is correct, but works better for one area, and worse for others? The latter. All models are the latter. The truth is unknowable.

As the parent says, to the extent that the model predicts our observations, it is consistent with reality. Many other models are also consistent with reality. This model may be simpler in some ways and less simple in others. If it is simpler in all ways and has predictions that are consistent with reality, we will use it in preference to other models.

Having said all that, I have no idea in which areas it is simpler, in which areas it is more complex and in which areas it conflicts with our observations.


Which is why I grabbed Newton's gravity model as an example. It's known to be a flawed model, only useful as a simplified approximation method that's "good enough" for many purposes.

It's like having a model that says "quack-like sound == duck". It's wrong. We know it's wrong. It may be useful when looking at birds, but it's 100% wrong when your hard drive produces the noise.

Of course it's a spectrum, but some of the things we hang on to and use are known to be false in a large way but still useful.


We could, one day, wake up to discover that we are actually living in the matrix. The rules of physics were only added by the machines to keep us amused so that we don't discover the true nature of our beings (batteries for the machines). Yeah... I don't believe it either :-)

But the key is that we can't know. Maybe "God did it" is the truth and the rest is just appearances. Maybe our mathematical constructs do represent reality closely. Even if we build models that are isomorphic to our perception of reality, there is still no way to tell if they are in any way similar to the actual workings of reality. The FSM can certainly alter our brains so that we just believe we see things happening in a consistent way, even though they are not.

Like I said, it is tempting to believe that the simplest solution that we can imagine is close to reality. This is very unlikely to be the case, IMHO. It's fine to believe it is, but that is not science any more. You are entering into religion.

Newton's laws are not known to be "more wrong" than relativity. Relativity matches our observations more closely and is simpler in some respects, but it could be just as wrong. Or more wrong. We have no way of measuring how close to reality our models are. We can only measure how closely they match our observations. As one of the other posters quoted: All models are wrong. Some of the are useful.

Even when you have a model that is completely consistent with observations it does not make it more likely to be correct. Imagine creating some byzantine model with a myriad of exceptions to explain away any discrepancy. Obviously as long as we accept complexity, we can model anything. These models are not usually useful though.

So as much as I understand that you want to ask, "Is this model more likely to be closer to the truth than other models", it isn't a question we can answer in science. We can only answer the questions, "Is this model consistent with our observations?", and "Is this model simpler than another model?"

The article claims that the model is at least as consistent as other models while being simpler in some instances. I think work needs to be done to verify those claims.


Yes, but now we're getting so metaphysical that all usefulness has evaporated. "Nothing is knowable" and all. I can agree, but it's a stance which provides no course of action.

We have a current best, or at least competing current bests. These may later be invalidated - that's fine, that's learning new things. It doesn't mean that everything we know now is indistinguishably-wrong as everything we thought we knew in the past. We can predict things now that we couldn't before.

We also have approximations that don't attempt to predict the system, they just produce useful results often enough to be retained - are these indistinguishable from all other attempts at describing reality?

How far do we take it? If Pi is 3, it may actually be true! It'd just invalidate a ridiculous amount of what we think we know. That's equal to quantum mechanics, which appears to have concrete applications.

---

Perfect is the enemy of good.

> The article claims that the model is at least as consistent as other models while being simpler in some instances. I think work needs to be done to verify those claims.

Great!


Well said. Models do not contain reality: reality contains models. Do not confuse the map with the territory, and all you have are maps.


I don't think anyone working in science believes any model they investigate is going to work without qualification for all time (for a limited time, with current ability to verify, sure; Newtonian gravity worked that way for a long time, too.)

Science approaches the underlying reality asymptotically.


All models are wrong. If a model is not wrong; it is called reality. http://stats.stackexchange.com/questions/57407/what-is-the-m...


This is the right answerer. It pains me that we humans, in our arrogance, do not keep this idea at the forefront of our minds and discussions. I believe far fewer mistakes would be made in science if we more readily accepted our limitations rather than being constantly so enthralled by our own apparent genius. It's not amazing that we amaze ourselves.


I like this mindset.

> It's not amazing that we amaze ourselves.

This realization is super assuring with the complexity of the discoveries broadcast on HackerNews. Sometimes it's overwhelming, but now I can think of it as a sort of... scale.


To me, saying that model or a theory is wrong is like saying a hammer is wrong. A tool cannot be right/wrong or true/false. However it can be unsuitable for a task. In this case, the task is understanding reality.


It is the second part of the quote (follow the link above): "all models are wrong. Some are useful" -- you are talking about the suitability/usefulness of a model.


Exactly, if your model has all the complexity of reality... then you're going to have a hard time understanding it or answering any question unless it is historical rather than prediction. They key is in the model being useful locally, and a big part of that is knowing where it is valid (e.g. Newtonian Mechanics is great for most things until you exceed micro/Tera scales). Then you can choose the right model to solve the right problem or answer the right question. Trying to figure out what every molecule in a gas is going to do will drive you crazy, but measuring pressure/temperature/entropy will often lead you to insight.

In my mind this is one of the problems that moral philosophy has fallen into... rule utilitarianism works because we are about as good at predicting how others would feel as we are for ourselves (i.e. mediocre, but not terrible). Most modern moral theory is so complex in order to deal with various oddities that we're terrible at using it in even the simplest cases.


Imagine performing a molecular dynamics simulation. Your simulation occurs in a 3D box, and if you visualize it, it looks three dimensional, but the way the information processing works is that you have a list of atom coordinates stored next to each other in one dimensional RAM.

It's kind of the same thing with the holographic idea. Information locality is 2D (information is "near" other information as if it were on a two dimensional plane), but our perception is that of a 3D universe.

(Standard disclaimer about loose analogies not reproducing mathematical equations...)


mumble mumble row hammer Einstein-Rosen bridge..


> is the holographic universe 'merely' a mathematical tool that helps us solve problems, or is it a description of an objective reality

Some would say there is no meaningful difference between those two. E.g. Max Tegmark in 'Our Mathematical Universe'.

I'm not saying he's necessarily right, I'm just pointing out that such a viewpoint exists.


I cant tell if all of the comments here are genuine, or the output of some high performance markov chains.

Also, i have absolutely no ability to penetrate what is being described by this article. Holograms work by applying lasers to different surfaces and re-rendering the image relative to the original laser's point of view. How does the word 'holographic' apply?


Holograms are 2d images that look 3d from our perspective.

Similarly, this theory is that our perceived reality of 3 spatial dimensions + time is actually fully contained on a 2d surface.


Thank you for taking the time to try to educate me.

I think that this metaphor is flawed. Holograms project an illusion of depth, but they clearly are not 3 dimensional. The metaphor falls apart if your thought process includes the assumption that eyesight is an unreliable depth detector.

There are other methods for detecting x/y/z coordinates that do not rely on eyesight- consequently, I'm having a hard time reconciling what the metaphor describes.

I feel that Platz's material below is more descriptive and helps communicate the concepts in a far less confusing way.


Black hole Firewalls with Sean Carroll and Jennifer Ouellette (45m+50s quick summary of the holographic principle) https://youtu.be/_8bhtEgB8Mo?t=45m50s

Leonard Susskind on The World As Hologram (more dense/verbose)

https://www.youtube.com/watch?v=2DIl3Hfh9tY


Are you implying that markov chains can't be genuine? :)


It's crazy to think we are the universe observing and trying to understand itself. Matter organised in a certain way is able to observe itself? How weird is that!


Pascal in "Pensees" used this perplexing notion to argue for the reality of the soul. Interesting to see people grappling with these ideas through the centuries:

"And what completes our incapability of knowing things, is the fact that they are simple, and that we are composed of two opposite natures, different in kind, soul and body. For it is impossible that our rational part should be other than spiritual; and if any one maintain that we are simply corporeal, this would far more exclude us from the knowledge of things, there being nothing so inconceivable as to say that matter knows itself. It is impossible to imagine how it should know itself.

"So if we are simply material, we can know nothing at all; and if we are composed of mind and matter, we cannot know perfectly things which are simple, whether spiritual or corporeal. ...

"Who would not think, seeing us compose all things of mind and body, but that this mixture would be quite intelligible to us? Yet it is the very thing we least understand. Man is to himself the most wonderful object in nature; for he cannot conceive what the body is, still less what the mind is, and least of all how a body should be united to a mind. This is the consummation of his difficulties, and yet it is his very being. Modus quo corporibus adhærent spiritus comprehendi ab hominibus non potest, et hoc tamen homo est. [The manner in which spirits are united to bodies cannot be understood by men, yet such is man---Augustine]."


How does one save comments? I would like to read up further on Pensees.


You can click the "favorite" link in the comment header. Note that favorited comments are public: anyone clicking through your profile can also see which comments you've favorited, if that matters to you.


This is the perspective that I hardly ever hear discussed when the issue of "human freedom" is brought up. If you assume we are a result of the big bang, then the causal relationship infers humans are not free. If on the other hand you assume humans "are" the universe, then an entirely different perspective seems to be possible albeit one that is much more confusing to reason about.


Daniel Dennet wrote a book arguing for the existence of free will despite the determinism of the universe.

It's called the evolution of free will. You might want to check that out if you'd like to know more about that perspective.


I have found that discussions on 'free will' tend to be doomed from the start because no-one can agree on a definition of free will.


Freedom of will is completely compatible with fully deterministic world. Just consider that there are many fully deterministic worlds but the one one perceives themselves in depends on freedom of choice.


Who chooses the world to perceive? How is the choice made?


That are implementation details. The point is that apparent determinism of the physical world has no implications for free will considerations and cannot be used as an argument against it.


Non-dual philosophies, such as transcendental non-dual Shaiva Tantra is based around that.


This and Godel's Incompleteness (equivalently the halting problem) and entropy (which gives the "arrow of time") I always find endlessly strange.


what about human consciousness?


"this" was referring to human consciousness (since I was referring to a comment about that)


Totally normal. I experience it every day!


What about it? Any collection of rocks put on a grid with certain rules can become "conscious". Neither your little awareness of yourself, nor someones feeling of "endlessly strange" things mean anything when talking about whether universe is holographic or not.


"God is consciousness, and we are all god trying to realize our full potential." --Hicks


Douglas Hofstadter (Godel, Escher, Bach) refers to this as a "strange loop".


It's interesting that to a layman this seems like almost the exact opposite of what string theory proposes dimensionally. Holographic universe theory is stating there are effectively less dimensions, while string theory shows there could be significantly more.


This is the first time I've read anything about Holographic universe theory and I really don't understand anything about it yet. But, does this mean we were the ones living in a 2-dimensional "flatland" the whole time?


One way to think about is what goes on in a video game - you see characters on screen, but in the computer you actually have some data-structures describing them.

So a Player data-structure maps to a Player on screen, in the same way that some configuration of qubits on the surface of the universe corresponds to some thing from the "bulk" that we see.


Does that mean there are more low-level 2-D laws of physics that give rise to the observable laws of physics? If yes, would we be able to access them?


So the earth is flat - told you so :-)


I think it means the max amount of information in the observable universe is bounded by the amount of information that could fit on the 2D surface of a spherical event horizon of a black hole of the same size.


That was the origin of the theory, but from what I understand it's been developed beyond that point.


Is there a why? I got curious.


If you take all the mass and energy of the observable universe and throw it into a black hole, its event horizon would expand and encode all the information you put into it. Information can't be destroyed so that's why it is encoded in the event horizon. The diameter of the event horizon would also be much smaller than the diameter of the observable universe, because there's a lot of empty space in the universe, and we don't see everything collapsing inwards due to too much mass. So if you had an event horizon with the diameter of the observable universe, it would encode a lot more information than what's in our observable universe. Note I'm just a layman here and I could be interpreting it incorrectly.


I'm not sure you're a 'layman' if you understand string theory.


Knowing that string theory requires 11 dimensions doesn't mean one understands it. And even string theorists aren't sure which version of the theory represents everyday reality, and the number of candidates is quite beyond imagining. Finally, to date there aren't any reliable empirical tests to place string theory on a firm scientific foundation.

In the long term string theory may contribute more to mathematics than to physics.


But a layman might conflate two things that they do not understand.


I thought that in order for a holographic universe to exist, then the universe needs to have a non-flat e.g. slightly-curved spacetime; in order to "close the boundary", so to speak.

But my understanding is that so far all our evidence shows that spacetime is flat?

i.e. we spacetime needs to be an Anti-de Sitter space. https://en.wikipedia.org/wiki/Anti-de_Sitter_space But I didn't think many actually think we live in an ADS universe?

Also relevant to string theory, https://en.wikipedia.org/wiki/AdS/CFT_correspondence


Couldn't the amount of curve within our observable universe be less than the margin of error in our methods of observation?


Of course.. big hologram though!


That's an interesting observation! Perhaps next we are going to learn that everything is - as the Buddhists keep teaching - indeed "one". I am saying this only half-jokingly. One thing you can derive from the statement that everything is one is that everything we can think of also includes what we would call the opposite of what we're thinking of . And thus it would be correct to say that the universe has many dimensions but it is also true that it has very few dimensions. This surely sounds somewhat anti-intellectual but it'll be fascinating to see if science will ever be able to come up with something more meaningful, i.e. something which is less contradicting.


You mean spatial dimensions. But space and time appear to be derivative notions anyway.

What really matters is the space of independent parameters (or, if truly independent parameters do not exist, then the truly fundamental ones). That would be really nice to figure out one day.


The holographic universe theory is derived from string theory. Specifically ADS/CFT correspondence:

https://en.wikipedia.org/wiki/AdS/CFT_correspondence


This is like the wang carpets from Greg Egan's Diaspora novel.


I'm having some trouble understanding this sentence:

" [...] our 3-D ‘reality’ (plus time) is contained in a 2-D surface on its boundaries."

What, exactly, do they mean with 'on its boundries'?


Think about it in terms of (dramatically oversimplified) category theory:

You can think of the rules of physics as requiring 4 parameters to specify things like position, momentum, etc -- (x,y,z,t). Imagine that you have a category of states in that space, and the physical laws are functions that take states to other states in that same category.

Now imagine you have some functor which takes those states and translates them to a new space that only requires only (x,y,t) to specify them, and translates the functions so that they now take those states to other states in that 2 spatial dimension category. And there's a one-to-one correspondence, so you can move back and forth between the two categories. So if you have states A and B in 3d and A' and B' in 2d, You can go from A to A' to B' and back to B and it's the same as going from A to B.

It turns out that the physical laws in the 3d category have gravity, and the ones in the 2d category might not. But the laws still correspond one-to-one.

The reason this is useful is that figuring out quantum gravity is really hard, and it might be easier to figure out the functor that translates 3d physics into 2d physics that lacks gravity, perform the calculations there, and then translate the result back to 3d physics.


I'm familiar with the idea of coordinate transforms and projections, so I get the idea that you could project our 3D universe onto a 2D surface, and I kind of see how a hologram encodes 3D information, but I don't see how that is a useful idea. Or are there only certain kinds of 4D information that can be encoded in the 2D surface, so our 4D model of space and time gets reduced to a theory of only 2 dimensions? Are there conceivable arrangements of a 4D universe that can't be represented in this way?


Having only read the abstract (so I might have it totally wrong) we have the 2D holographic picture from the cosmic microwave background already and we're trying to fit that data to various theories. The cool kid theory used to revolve around dark matter in some way I'm a little unclear on. If you run a bunch of simulations on imaginary 4D universes playing games with the usual cosmological parameters, sometimes with some parameter settings processing the results as a holographic projection gives better match to the pix we already have, than stuff done that relies on dark matter and things. Quantum field theory mixes into this which is interesting because that usually applies to little things not the shape of the universe size stuff.

I'm working on an automobile analogy but its not easy.


Laymen "easy" language makes everything harder to understand.

The holographic principle means that if you take a sphere somewhere, the amount of entropy you can push there grows with r^2, and not with r^3 like you'd expect.


Thanks a lot. I've just watched susskind talk on the universe as a hologram ( https://youtu.be/2DIl3Hfh9tY ), and it didn't occured to me until i read what you just said simply that the holographic principle meant you could actually push less stuff / bits in a black hole by growing it, than you first thought if you compared it to a volume growing. So that meant information was stored on its surface (r^2), and not inside it (r^3).

Am i correct ?


Keep in mind that IANAP.

The information stored is proportional to the surface, not volume.

But also, the holographic principle applies to more than black holes. At any volume, the maximum information you can put there is proportional to r^2. That applies to all the volumes inside the volume you just measured... what means that a volume can not be completely full (a weird case of apparent non-locality).

An hologram is a better analogue to it than information being stored on the surface because, outside of black holes it apparently isn't all on the surface. (I guess for the black hole information loss problem, information being in the surface or in a hologram don't make much difference.)


This is a statement of the holographic principle, which is that a projection on the surface (boundary) of a volume completely encodes the contents of that volume. You then no longer need the volume at all, you can perform all operations on the surface projection instead.


Have you ever seen a hologram?

Shine lasers on a 2-D surface, and interference patterns create a 3-D image in mid-air. You see a 3-D object, but all information is actually stored in 2-D.

This is the same idea.


It's an awkward sentence. The 2-dimensional surface is the boundary of the 3-dimensional surface. I think what they're saying is that they believe the 3-dimensional universe is a 'reverse-projection' from the 2-dimensional surface.


I wonder if this theory supports the idea that the universe inhabits a black hole, or at least the surface of one.


Actually, the big bang bears a pretty striking resemblance to a white hole. That's the time-reversed version of a black hole. Whereas with a black hole, all paths lead toward the singularity at its core, with a white hole, all paths lead away from the singularity.


And there you go... there's the answer to everything. A black hole on one side and, on the other side (the side we don't know), there's a whole new universe being sprung up. Each input goes to the output of a different black/white hole combo.


Tempting, but there's no evidence to support that.


Indeed, but there is research underway to find evidence:

<< Black holes are extremely dense and compact objects from which light cannot escape. There is an overall consensus that black holes exist and many astronomical objects are identified with black holes. White holes were understood as the exact time reversal of black holes, therefore they should continuously throw away material. It is accepted, however, that a persistent ejection of mass leads to gravitational pressure, the formation of a black hole and thus to the "death of while holes". So far, no astronomical source has been successfully tagged a white hole. The only known white hole is the Big Bang which was instantaneous rather than continuous or long-lasting. We thus suggest that the emergence of a white hole, which we name a 'Small Bang', is spontaneous - all the matter is ejected at a single pulse. Unlike black holes, white holes cannot be continuously observed rather their effect can only be detected around the event itself. Gamma ray bursts are the most energetic explosions in the universe. Long gamma-ray bursts were connected with supernova eruptions. There is a new group of gamma-ray bursts, which are relatively close to Earth, but surprisingly lack any supernova emission. We propose identifying these bursts with white holes. White holes seem like the best explanation of gamma-ray bursts that appear in voids. We also predict the detection of rare gigantic gamma-ray bursts with energies much higher than typically observed. >>

https://arxiv.org/abs/1105.2776


> The only known white hole is the Big Bang which was instantaneous rather than continuous or long-lasting

Even if the Big Bang was a continuous long-lasting process of energy/matter appearing, wouldn't the effects of General Relativity make it look like, from the perspective of observers later on within the Universe, that all the energy/matter appeared instantaneously?


Right... that's why it's a theory. A humorous, non-serious theory, but a theory nonetheless. (Replace with hypothesis if you want to get really pedantic about it)


Absolutely correct... but continue down the path of wild, unjustified speculation... perhaps then "Dark Energy" is nothing more than "Hawking Radiation" as it appears from a perspective within the black hole. :-P


I don't think there's any way to validate any holographic theory.


So basically, we're in a cable?


How many universes can we daisy chain together?


I'm more worried about when the universe decides to start dropping ports and making everything wireless. :-P


Needs a dongle


if time actually runs backwards a lot of things would make sense


Very misleading title! This article doesn't really discuss the "evidence", you will need to dig deeper. The article is a summary of what holography is, and not much more.

> They found that some of the simplest quantum field theories could explain nearly all cosmological observations of the early universe.

This seems to be very, very old news. Like all theories, holography sounds very interesting. This article implies that a prediction made by holography has been observed. This is not the case, apparently. The math may a lot more elegant, but what new predictions are there, and have we observed them? This is what the article claimed to be about, alas it wasn't.


There's good background information in the Wikipedia article on the Holographic principle:

https://en.wikipedia.org/wiki/Holographic_principle

The latest Scientific American has an article on why some physicists are calling for rejection of cosmic inflation theory:

https://www.scientificamerican.com/article/cosmic-inflation-...

Although it seems to be paywalled.


A friend of mine has been trying convince me and my peers for like 2 years that the universe is holofractal. Holofractal is different than holographic [1] but is also an interesting idea.

Things like the Em Drive device and this are really making physics interesting again.

[1] https://www.reddit.com/r/holofractal/comments/5r3i83/hologra...


This shows how philosophy is rather important when trying to come to an understanding.

Different philosophy can result in different theory of explanation and different direction of model building.


agree very so much. I responded to another answer where someone's comment was questioned as being poetic or metaphorical and not scientific. :)


As a non physicist, there's something I don't get in the comparaison with 3d tv. From what I gathered, the only reason 3d tv is 3d is because it exploits the fact we have two eyes, distant from one another, which can provide a depth view when seeing the same thing at two different angles, or when being tricked into thinking it's that way.

What would mean a "holographic 2d space encoding 3d space" detached from an illusion made by someone observing it?


What does this mean?

The universe is fake? Is this along the same lines as "everything is a simulation"?


Holographic theory is not the same as the universe being a simulation. I have only done basic reading and following of the idea but as I understand things, the "holographic" universe is about figuring out how our experience is encoded in the fabric of the cosmos. It's another step in trying to find the universal equation that works at the big (gravity / relativity) and the small (quantum).

If the holographic information is itself a simulation is another level of discussion entirely!


Does this mean it could be theoretically possible to warp between two locations utilizing the 2d properties of the unprojected universe?


Holographic means that the universe appears 3d but is actually 2d.

'appears' means that for us it is three dimensional.

'actually' means that the amount of stuff universe can hold is limited by 2d surface area, not 3d volume. Information/matter contained in universe is in '2d container surface' while interactions between them seem to happen in 3d universe.

In other words, the information/matter you can keep in volume of space is limited by it's surface area and not it's volume. If you try to add more, it becomes black hole.


Is it misunderstanding things to say that we're like data on a computer? So from my perspective, two atoms on my body are right next to each other. However, they could be theoretically encoded on opposite ends of the universe's 2d surface?


The analogy no one wants to state in public (because its partially wrong) is holography is like Fourier transforms or x-ray crystallography.

Today everyone is very chill with using FT to convert say a pile of voltage and time measurements into frequency/phase and power, and back again, and manipulate either side to see how the other side wiggles in response. This is all basic EE stuff this is how your DSP or software defined radio works (well, not exactly but close enough)

Photo negative human scale holograms use monochromatic light to store all kinds of interference pattern stuff into splotches of black and white. If we were (are?) smart enough we could print out something on photo paper and shine a laser on it and a hologram would appear.

Another analogy which is pretty decent is its like x-ray crystallography where about half a century ago a popular use of computers was to take a crystalline material and shine xrays thru it making a very modern art ish looking photo of holographic interference patterns (sorta) which would be analyzed by a computer to reverse the transform and turn it back into a 3-d model of the atoms in the crystal.

So a lot of this is almost cryptographic hash like in that flipping a couple bits on one side almost always results in a huge change on the other side.

So if instead of talking about atoms you take a film and laser hologram of two coffee cups the splotchy hologram film doesn't really have a concept anymore of two coffee cups next to each other, you can't point to a splotch and say thats the cup on the left. You definitely can't slice the film in half and project each and expect one cup on each half, probably you'll have two holograms each with two coffee cups and 3 dB or so worse signal to noise ratio.

Badly mixing analogies its like running a crypto algo on 2 bytes of data and asking where exactly the two bytes are in the output. Well, um, if the crypto algo is anything better than ROT13 they're both kinda smeared everywhere across the output of the algo.

Really badly mixing analogies its like taking a .scad file storing a 3d object (or stl or cad program of your choice) and encoding it into one of those legacy 2-D QR codes and then asking where in the QR code can you see your 3-d object ...

The whole point of this is we kinda sorta have a 2-d holographic picture of the cosmic background radiation sorta. Its a very distinct picture. So whatever crazy simulations we try, we'd best make sure if you hologram-ify the cosmic background radiation, it best look similar to what our telescope have already seen. Kind of like stellar astrophysics isn't just making stuff up, your theories better match what spectrum analysis of star light often actually looks like, if your nifty stellar astrophysics theory predicts Sirius is a red giant or a black hole or something then your theory is messed up because we have lots of data about the real Sirius as opposed to theoretical models.


Nope, not fake. Just another way to look at it. From the paper: "One of the deepest insights about quantum gravity that emerged in recent times is that it is expected to be holographic [1–3], meaning that there should be an equivalent description of the bulk physics using a quantum field theory with no gravity in one dimension less. One may thus seek to use holography to model the very early Universe."


IANAP, but no, it's saying that our current 4-dimensional spacetime is a holographic projection from an earlier 2-D phase of our universe. Not that it is currently 2-dimensional.


Think of it, as if God is pulling a joke on us or the physicists.


Why all the down-votes? I'm an atheist and I found this comment amusing.


Can you elaborate on this slightly? Genuinely interested


No, it doesn't mean anything about being a simulation or not, but it imposes lower limits in the information it can contain.


The abstract of the paper about which the article reports is less dramatic:

https://arxiv.org/abs/1607.04878

"By comparing the Bayesian evidence for the models, we find that ΛCDM does a better job globally, while the holographic models provide a (marginally) better fit to data without very low multipoles."

So the non-holographic model seems to be better globally even according to the paper.

https://en.wikipedia.org/wiki/Lambda-CDM_model

If the further research proves that holographic models are better, it's good too, let the best wins. But at the moment it still looks to be too early to conclude too much.



Consider a mathematical spherical construct that contains more than the the r^2 amount of entropy than can be described by the Holographic Principle. What makes that not possible under the theory? What breaks down? Is there a physical analogy for it?


From https://en.wikipedia.org/wiki/Holographic_principle:

'However, there exist classical solutions to the Einstein equations that allow values of the entropy larger than those allowed by an area law, hence in principle larger than those of a black hole. These are the so-called "Wheeler's bags of gold". The existence of such solutions conflicts with the holographic interpretation, and their effects in a quantum theory of gravity including the holographic principle are not yet fully understood.'


to me it like classical electrodynamics ie. like Gauss's law connecting field on the closed surface with what is inside. The key in classical EM is that EM field is holomorphic, and the gravity in GM seems to be close to that too. So in that sense holographic principle is something like this - integral of information flux taken over closed surface equals the integral of the information [charges] taken over the enclosed volume, and thus the upper limit of r^2 is just being a simple consequence of the equality in the situation of maximum entropy (minimum information) situation of a black hole (with gravity being fully compatible with [and alternatively reformulated through] entropy description a black hole is the ultimate gravitational as well as ultimate entropy state).



IANP, but its seems as if the measurement problem will always cause us to observe, more accurately measure, a 2D projection and maximum entropy; where before the wave collapse a 3D+ universe and perhaps infinite entropy existed.

In the same way that two trains traveling at different speeds are warped to the observer, it would seem to me that we would need to observe the wave in real-time to accurately observe it.

Again, INAP.


The headline is tantalizing, but this is almost impossible to grok for a layperson like me.


Does anyone know how could affect that to wormholes? [1]

[1] https://en.wikipedia.org/wiki/Wormhole


Does this mean that consciousness is a dimension? Would a (say) lifeless planet 'be' 3D if not observed or would it remain encoded in 2D? (Asked by a layman).


The Holographic Universe: The Revolutionary Theory of Reality by the late Michael Talbot is a must read for those interested in exploring this topic.


So now the entire universe is 2D?

Wow, these flat-earthers are getting ambitious.


Maybe my clock is time-dilated, but isn't 1st of April still months away?


Shitty scientific journalism. Abstract says something else but who cares.


The abstract:

>We test a class of holographic models for the very early Universe against cosmological observations and find that they are competitive to the standard cold dark matter model with a cosmological constant (ΛCDM) of cosmology. These models are based on three-dimensional perturbative superrenormalizable quantum field theory (QFT), and, while they predict a different power spectrum from the standard power law used in ΛCDM, they still provide an excellent fit to the data (within their regime of validity). By comparing the Bayesian evidence for the models, we find that ΛCDM does a better job globally, while the holographic models provide a (marginally) better fit to the data without very low multipoles (i.e., l≲30), where the QFT becomes nonperturbative. Observations can be used to exclude some QFT models, while we also find models satisfying all phenomenological constraints: The data rule out the dual theory being a Yang-Mills theory coupled to fermions only but allow for a Yang-Mills theory coupled to nonminimal scalars with quartic interactions. Lattice simulations of 3D QFTs can provide nonperturbative predictions for large-angle statistics of the cosmic microwave background and potentially explain its apparent anomalies."

So, basically, the holographic models seem to be pretty good, in the areas where it is perturbative (roughly l>30), it appears to fit slightly better than the current theories ("lambda CDM" models). The paper can rule out some of the holographic models because they don't fit the data, while other models fit great. Finally, the non-perturbative holographic models (roughly l<=30) might be able to be made to fit the data better if they are not calculated in a perturbative sense.

This seems to be pretty close to what the article says...


What new evidence a model brings? Model can be used to plan experiment based on it and that is evidence (once you carry out the experiment that is). Model is only used to explain how stuff is supposed to work.

Please read conclusion section of the paper.

example: Epicycles also explain how planet movement works - but it is not evidence how it works it is explanation based on data.


Is this actually evidence or lack of proof against?


The abstract says:

> We test a class of holographic models for the very early universe against cosmological observations and find that they are competitive to the standard ΛCDM model of cosmology. These models are based on three dimensional perturbative super-renormalizable Quantum Field Theory (QFT), and while they predict a different power spectrum from the standard power-law used in ΛCDM, they still provide an excellent fit to data (within their regime of validity). By comparing the Bayesian evidence for the models, we find that ΛCDM does a better job globally, while the holographic models provide a (marginally) better fit to data without very low multipoles (i.e. l≲30), where the dual QFT becomes non-perturbative. Observations can be used to exclude some QFT models, while we also find models satisfying all phenomenological constraints: the data rules out the dual theory being Yang-Mills theory coupled to fermions only, but allows for Yang-Mills theory coupled to non-minimal scalars with quartic interactions. Lattice simulations of 3d QFT's can provide non-perturbative predictions for large-angle statistics of the cosmic microwave background, and potentially explain its apparent anomalies.

The evidence appears to be "this is almost as good as state-of-the-art normal cosmic inflation theory." Which is to say, it's more of a lack of proof against than strong evidence for--it's not providing explanations for unexplained observances.


Hmm, this actually makes me much more excited. I finished with grappling existential issues about being a simulation a long time ago; I don't see the point anymore. But if I understand this right, this would give us reason to believe we could simulate absolutely tiny models of the universe with relatively high (still quite low) confidence it's meaningful. Is that fair?


Your summary was almost exactly what I was going to write, based on the abstract.

That said, though, a not-quite-as-good match after a very few years' work is kind of promising. After as long as the standard model has been worked on, the match might be as good.


You cannot code a particle simulator that perfectly mimics 3D space despite each particle only having two spatial location variables.

We all have that new agey friend on FB who will inevitably share this nonsense. Do we really need to be dealing with it on HN? What's next, Minion memes?


The holographic principle proposes a much more complex relationship between the 3 dimensional (plus 1 time dimension) universe we experience and a 2 dimensional (plus 1 time dimension) model that could provide insights into many interesting areas of physics including QFT, Cosmology, Black Holes, etc.

There is a very well developed model of how this relationship could work in a simpler case. I suggest you have a look at this wikipedia page: https://en.wikipedia.org/wiki/AdS/CFT_correspondence

Hopefully this mathematical model will convince you that the holographic principle is, at the very least, more mature than a minion meme.


How a simulation could reveal anything? A simulation has no connection to reality whatsoever. One single major (or even minor) factor missed in the model, and the whole thing is a bullshit. Imaginable factors with real weights - same kind of result.

Simulations and probabilistic estimations could be applied only to fully observable environments.


Where did you get that this was a simulation? The were analyzing telescope data.


Analysis presupposes some model.


The entirety of physics is a bunch of models that match reality to various degrees, and which are able to predict things.


That does not mean that unproved (non-existent) factors should be added to a model or that any inferences could be made from a simulated model.

Experiment, not a simulation is the criterion of validity in the scientific method. Simulation is not a valid experiment.

Hypotheses and predictions are guesses, not facts and cannot be substituted for facts or logical premises.


While not conclusive, does this not sound like support for what could be Intelligent Design - ID?

'Patterns imprinted in it carry information about the very early Universe and seed the development of structures of stars and galaxies in the late time Universe.' [From the Bulletin]

If the universe is encoded on a 2d surface and has been projected on 3d, doesn't that sound like some design/intentional purpose encoded on the 2d surface?


You can always inject god into the unknown. That's what history has shown us over and over and as we slowly uncover how things work there are fewer places to put god into. I see no difference here.


No. This emerged from studying what happens when stuff falls into black holes.

In physics, all matter can be described as having "information" or "state" that describes itself. That information can't be destroyed. However, a questions about how matter's information was preserved in a black hole led to math equations that describe how that information is "encoded" onto the black hole's event horizon. As a funny side effect, those equations also happened to describe everywhere else in the universe, leading physicists to look around and ask themselves, "Are we holograms too?"

In this way, the Hologram theory states that all matter is really information on a 2D surface, and that "we" are the 3D holographic projection of that information.


Why? It doesn't seem to bear any kind of relevance either way.




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