Slashdot Mirror
Simulations Back Up Theory That Universe Is a Hologram
ananyo writes "A team of physicists has provided some of the clearest evidence yet that our Universe could be just one big projection. In 1997, theoretical physicist Juan Maldacena proposed that an audacious model of the Universe in which gravity arises from infinitesimally thin, vibrating strings could be reinterpreted in terms of well-established physics. The mathematically intricate world of strings, which exist in nine dimensions of space plus one of time, would be merely a hologram: the real action would play out in a simpler, flatter cosmos where there is no gravity. Maldacena's idea thrilled physicists because it offered a way to put the popular but still unproven theory of strings on solid footing — and because it solved apparent inconsistencies between quantum physics and Einstein's theory of gravity. It provided physicists with a mathematical Rosetta stone, a 'duality', that allowed them to translate back and forth between the two languages, and solve problems in one model that seemed intractable in the other and vice versa. But although the validity of Maldacena's ideas has pretty much been taken for granted ever since, a rigorous proof has been elusive. In two papers posted on the arXiv repository, Yoshifumi Hyakutake of Ibaraki University in Japan and his colleagues now provide, if not an actual proof, at least compelling evidence that Maldacena's conjecture is true."
I have no idea what any of this stuff means, but I'm going to post it on my Facebook and claim that this is what I thought all along anyway.
who appear to us as mice
Then they will tell you it is recursive too.
But it happened long time ago and in a galaxy far away.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
I hate to tell you but not all scientists are doctors, and also cancer is not the only issue that is affecting us today. The more we understand about the universe, the more we understand about ourselves.
In other words, what are YOU doing to cure cancer since you think that "scientists" should focus on cancer instead of XX.
have you seen my sig? there are many others like it but none that are the same
why oh why are scientists wasting time on this? one step at at time, for now figure out how to cure cancer before worrying about the big picture. you must unzip your pants before worrying about how much piss comes out
Really???? If all "scientists" thought like that then we wouldn't be in a position to even KNOW what *cancer* is. We'd be stuck on a problem prior to that hundreds of years ago.
Science is all about looking far and wide for answers. Sometimes things are immediately applicable to your specific problem/condition/annoyance/life, but sometimes they aren't.
Applied science / engineering is more about solutions to your specific problem. Perhaps you can go ask the bio-medical engineers to hurry it up, but leave the scientists alone!
why are you wasting time reading Slashdot? Millions of children are dying in Africa as we speak. You must go help them before worrying about anything else.
Quite a lot older.
A lot of people might find this a little hokey, especially coming from the journal Nature. The biggest thing to overcome is science fictions deception of other dimensions. A dimension is just another direction. We know about the six directions we can currently move in (3 dimensions) plus time (which we always move forward through at a constant rate; you can slow down how fast you move through time relative to everything else, but it's not noticeable unless you can afford a very very fast vehicle). Here's a great explanation of extra dimensions:
http://www.phdcomics.com/tv/#010
The other "Things explained" videos are also really good for understanding more complex physics concepts.
Well I was wasting time reading it for fun but now I'm doing it out of gut-wrenching depression that I'm not doing anything worthwhile.
There's more about it here. This recent work basically suggests that the theory might be true. It is a doubly useful theory in that it allows certain difficult problems in string theory to be solved in the language of conformal field theories and vice versa. If nothing else, it means string theory can be used as a computational tool in certain problems of condensed matter physics even if string theory doesn't pan out as a theory for quantum gravity. But it also makes string theory more likely as a theory for quantum gravity as it makes it in some sense compatible with the holographic principle, which among other things provides a solution to the information paradox of black holes.
If I can be modded down for being a troll, can I be modded up for being an orc, or a balrog?
I read the FTA and I didn't get any proof that we were living in a simulation at all. The article basically says some physicists ran two simulations for a black hole -- one with quantum theory (single dimension) and the other with a (more traditional) 10-dimensional model. The results matched.
Several take aways: 1) Great work by the physicists 2) I thought the standard models had eleven dimensions and not ten 3) I still don't know what they are talking about because this stuff is way beyond me 4) There is no mention about whether this proves one way or another that our universe is a hologram or a simulation.
The FTA is throwing around the word hologram, but IMHO that is a bit a stretch. Or maybe I don't know the official scientific definition of a hologram.
You do realize that quantum mechanics were met with similar derision? Heck, Einstein never really accepted the notion, and that's as great a scientist as we've ever had. It took years to devise experiments that could validate quantum mechanics' existence.
This isn't to say that this theory is right or wrong, merely that groundbreaking theories almost invariably will look like "mathematical fancy" to most people (especially those with "get off my lawn!" syndrome) and will be met with confusion or denial by a lot of others, including respected scientists. It's crazy, but it might just work. Remember: the universe wasn't designed so that our puny minds would find it logical or straightforward. It just is.
I think it's more probable that you just have no idea what you're talking about.
The hot grits are still real to me, dammit!
"Unheard of means only it's undreamed of yet,
Impossible means not yet done." ~~ Julia Ecklar
Is this related to the work that Arkani Hamed and Trnka are doing with Ampletuhedrons? They have discovered a geometry that simplifies calculations and that suggests space and time might not be fundamental to physics.
nonsense, it makes boobs awesome holographic porn, projected from a surface.
Someone clever was working out the maximum entropy of a black hole, and found that (unexpectedly) it was proportional to the surface area of the event horizon, not its volume. After some more thought, other clever people found that the full state of every particle that falls into a black hole remains encoded as oscillations and deformations of its surface area.
This leads to the realization that the despite the fact that a black hole's event horizon is seemingly much simpler than a full-dimensional portion of a universe, it's theoretically possible that it's just as rich a simulation. Perhaps the "real" representation of the universe is actually just a rippling membrane, and the 3D view we see around us is just an alternate interpretation. This is where the word "hologram" comes in - it's only an analogy (because flattish holograms seem to encode 3D data).
Now, the word "real" is misleading - neither representation is 'more true', it's just that the fewer-dimensional representation might be a lot simpler. A comparable situation is the way the earth goes around the sun, or the sun goes around the earth. A stationary sun makes models of the planetary orbits a heck of a lot simpler, but a stationary earth makes it a lot easier to give directions to your party.
All of this was theoretical until this recent finding. The researches created two mathematical models of the universe - one of them ten-dimensional (similar to some forms of modern theories of our universe, though the article points out their model was simpler). The other model was a one-dimensional universe filled with ideal springs. These models were identical, in the same way as the 3D universe and the event horizon - they're alternate ways of calculating the same thing.
The researchers discovered that simulations in both of these universe models have the same output - in other words, they do seem to be different ways of describing the same universe.
The way I think of the universe, is like a 11 dimensional sphere of putty, that got hit with a hammer. (aka the big bang).
So, the sphere got deformed spraying outward in 3 dimensions (space) while flying off into a 4th (time) and the other 7 dimensions got compressed.
A Particle is a bit of energy caught in a loop around some number of those 7 dimensions, each combination of possible wrapping gives a different fundamental particle, with antiparticles having the same wrap, but opposing spin.
Light/radio 'waves' are caused by the photons looping around one of the higher dimensions, not one of our 3 spatial dimensions, which is how it is travelling in a straight line space, yet still taking a wavering path; like a piece of string wrapped around an infinitesimally small cylinder.
But that's just my mental model, it work well enough to keep me from going mad (I think)
So, the headline is quite wrong. Nothing in this work has directly to do with our universe, nor does it show that we live in a hologram. What it does do is provide some further evidence for a string theory conjecture called AdS/CFT. This conjecture says that "string theory in d dimensions" is precisely the same as "conformal field theory in d-1 dimensions". This is cute, since it lets us calculate some things, for example, one might be interested in calculating something in some field theory, but it is very difficult to do. AdS/CFT lets us translate that thing into a string theory thing, which usually is easier to compute. So people working in condensed matter physics, particle physics and QCD are actually using this string theory conjecture as a computational tool. However, AdS/CFT tells us nothing about our universe, since we know that the type of string theories it talks about can't describe our universe. So it is "only" a useful toy model and computational tool. The article is about that some guys have run computer simulations to calculate something on both sides, so both on the string side, and in the field theory side, and what they get match, as it should if the conjecture is true. This is nice and lends further evidence to the conjecture, but there is plenty of other evidence already known, both numerical and theoretical. So I fail to see how this is important or newsworthy, it feels mostly like useless hype.
If I understand this wikipedia article correctly, it's a projection of the universe's cosmological event horizon. So think of it as being caused by turbulence the "blast wave" produced by the big bang.
Eleven vs Ten dimensions is at the heart of the "hologram" thing. The universe as a hologram (nothing at all to do with a simulation) is a metaphor for how the math worked out in a very surprising way from two different directions.
In the study of black holes, a block hole represents the maximum entropy is is possible to have in a given volume. That there is a maximum possible information needed to completely describe a volume of space. Surprisingly that limit grows with surface area, not volume. By analogy, this is like saying you could take a holographic recording of a volume at its surface, and completely reconstruct the volume from that data. But the "holographic universe" is just an analogy for the very odd result that all the information describing a volume of space "fits" in 2 dimensions. It's best not to read too much into that because the limit here is really quite high, the maximum possible information is on the order of the surface area of a sphere measured in plank-lengths - vastly more bits than is likely relevant to anything.
Inspired by this work, but in completely unrelated theory, it was found that the 11-diminsional quantum model can be completely captured in a 10-diminsional model that includes gravity. The presence of gravity in the universe "flattens" the state needed to describe it by one dimension. This was to me a much more interesting result that the black hole result (because the numbers there were so high it wasn't really a limit at all). Qualitatively all this is not that surprising in glorious hindsight, because gravity does limit the possible ways to arrange matter in the universe: black holes mean any arrangement with too much too close together collapses the information needed to describe it into just a few numbers. How that translates into needing 1 less dimension in quantum mechanics is far beyond me.
Socialism: a lie told by totalitarians and believed by fools.
Basically, there are two major concepts.
First, is duality. This is where two models can represent the same system (they are duals of each other). The thing with duality is that in many cases, a problem that is impossible to solve in one model may be trivially done in another. You may know the duality between time-domain and frequency-domain systems - a convolution in one is a multiplication in the other (which is handy for some really difficult convolutions).
The other concept is a hologram. Take a traditional hologram you can buy as a souvenir - it's just a flat piece of transparent material (glass or plastic), yet look through it and you see a 3D image hovering in space - projected if you will, in 3D. And it is 3D, because you can look around the object. Yet the object is stored on a 2D medium. (FYI - the same concept applies to holographic sights - the dot is projected on the target in 3D space). Holograms are useful because they can cast higher dimensional spaces into lower dimensional spaces, yet retain the original resolution and details of the higher dimensional space (or how they get a 3D projection on a 2D surface).
Holographic theory is one where our 3D world is actually on a 2D surface. Like a hologram.
Now, what the results are is that they found a set of dual systems that represent reality - between string theory and quantum mechanics using holographic theory. In other words, they could do a calculation using string theory and have the results line up with quantum mechanics (and holograms). By proving this, a difficult problem in quantum mechanics can be translated to string theory and be easily solved there, then the results translated back, which gives the same answer as if you did it the hard way.
My layman's understanding is that string theory is what you get when physicists try to compromise.
Problem is, we have two models of the universe. There's the model that describes gravity, and the model that describes everything else. Since these are mathematical models, it should be possible to have a single unified model that can describe both other models accurately under appropriate conditions, but the two models are different enough to make that difficult. Whatever that ultimate unified model is, it's probably something complex and hard to really understand fully.
That's string theory. It's a physical description of the math that makes the models make sense together. We don't really know how to prove it's right or wrong, because we can't observe it directly. Since its inception, the math has required a few logical leaps and assumptions that are not quite rigorously proven true... yet. Depending on which of those assumptions are accepted at any particular time, there are indeed several variations and possible implications that can be inferred. This doesn't necessarily mean the idea is invalid, but just that more mathematical work (such as in TFA) is needed before we can really say we know what's going on.
The terms "simulation" and "projection" are also used in an unusual sense here, as well. They refer to our observable universe being only the result of a system we can't observe directly, much like a projection on a screen or a simulation inside a computer. Ultimately, understanding the mechanism that's actually running the "simulation" could open the door to new phenomena in our universe that we haven't observed before.
You do not have a moral or legal right to do absolutely anything you want.
...2) I thought the standard models had eleven dimensions and not ten ...
Look, the standard model has these eleven- *CRASH* - Oy! I mean ten - TEN dimensions!
Dark Reflection
nonsense, it makes boobs awesome holographic porn, projected from a surface.
RT or Pro?
I can see your point, but as long as it makes predictions I'm willing to keep it in a separate category.
I think you missed a bit there.
Any simulation of the world will be as complex as the original. So if you build a full simulation of the real world, you'd double the information complexity of the world. So that wouldn't work.
One thing that might work is if you simulate regions of the "world" just in time -ie the things you see are being simulated as you look for them. That ties that simulation to a Matrix like world - each person effectively has his own world and they can be independent of each other.
Another possibility is that we are in a limited simulation - some have said that quantum theory shows the graininess of the simulation and that relativistic speed limits limit the size of the canvas on which the world is being painted (ie you only have to simulate as far as the edge of the canvas, nothing outside it affects whatever is inside).
In either of these cases, you cannot (be guaranteed to be able to) run a simulation within a simulation.
http://slashdot.org/submission/1062723/Cheap-mobile-data-plan?art_pos=2
A very crude analogy would be a Fourier transform. If you take a simple wave it is very complicated to describe it in time domain (lots of terms mathematically), but it has a simple mathematical expression in frequency domain with just a single term.
The physicists have figured out how to simplify the maths. This transformation also has a physical interpretation which is best explained as a hologram. A hologram has information from 3 dimensions scrunched into 2 dimensions, ie when you look at a hologram, it appears to have depth. In a common hologram sticker, that information is encoded in polarization. In the same manner, they seem to say information in a 11 Dimensional world can be scrunched into lesser number of dimensions. Hence the analogy.
http://slashdot.org/submission/1062723/Cheap-mobile-data-plan?art_pos=2
Why do you automatically assume that the game is someone else's? They've made some huge advances in context-suppression in the latest generation holosims - you almost totally believe that the simulation is the whole of your existence and can, among other things, truly experience the wonder and horror of being a corporeal human in the early 21st century (one of the most popular scenarios, just look at the in-game population!)
Oh, wait, I'm not supposed to discuss such things on the in-game forums. Forget I said anything.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
One can manipulate math to to describe or answer pretty much anything you want. Just because the equations match what's happening does not mean they describe what's going on.
Who cares? As long as the equations match what's happening (and what's going to happen), does it matter what's "really" going on? We've been doing quantum mechanics for almost a century now, and still no one actually knows what it all means - but we're perfectly happy to take advantage of QM in our technology.
Certainly, you can describe anything with equations, and you can come up with multiple mathematical descriptions that match what you know. But they'll make different predictions, which can be tested, and that's where the value of generating a mathematical description is. If you're not looking for predictions you can just say "that's the way it is," skip the math, and move on to something else.
Hey, maybe _your_ universe only has ten dimensions, but _my_ universe goes to eleven!
This Space Intentionally Left Blank
"So you should major in subjects like English, philosophy, psychology, and sociology -- subjects in which nobody really understands what anybody else is talking about, and which involve virtually no actual facts. I attended classes in all these subjects, so I'll give you a quick overview of each:"
"PHILOSOPHY: Basically, this involves sitting in a room and deciding there is no such thing as reality and then going to lunch. You should major in philosophy if you plan to take a lot of drugs...."
http://users.soe.ucsc.edu/~martine/light/barrycollege.html
Unfortunately, some aspects of physics are starting to sound like Dave Barry's take on Philosophy..
One can manipulate math to to describe or answer pretty much anything you want. Just because the equations match what's happening does not mean they describe what's going on.
Who cares? As long as the equations match what's happening (and what's going to happen), does it matter what's "really" going on? We've been doing quantum mechanics for almost a century now, and still no one actually knows what it all means - but we're perfectly happy to take advantage of QM in our technology.
Yes, it really matters. In the middle ages, there were mathematical formulas which described the planets and sun revolving around the earth. The math worked very well even though the theory was proven to be very wrong.
Math, particularly when used as a language, can be used to describe all sorts of things. As with the spoken language, one can create a sentence that is technically and grammatically correct, but still is nonsense. The whole purpose of langauge, any language, even mathematics is to convey ideas. So, yes, it really does matter what's going on. That's the whole point of using a precision language, like math, in the first place.
I got into this discussion too late to be noticed, but I feel the need to help people understand that this theory is *NOT* stating the universe is a simulation. Projections are not simulations.
What the theory suggests is that of all the dimensions we know about (the article mentions 6, which is how many dimensions you get with one flavor of string theory), some of them are illusion. Like a hologram -- a 2D plastic or glass toy that displays a 3D image. The universe does not contain 6 dimensions; it contains a smaller number, and the rest of the dimensions only appear to be there.
It's likely that the universe contains at least three dimensions, because we would have noticed non-isomorphic behavior in space. But the jury is still out on whether the fourth dimension -- Time -- is an illusion. The same goes for the fifth and sixth dimensions.
None of this says anything about the universe being simulated. That's a philosophical question that physics will probably never be able to answer.
Genocide Man -- Life is funny. Death is funnier. Mass murder can be hilarious.
What do you mean it was proven wrong? It never was, and it hasn't been yet. It probably can't be. (Well, except in the sense that Newtonian Mechanics was wrong.)
What was proven was that the heliocentric theory was a lot easier to calculate. And you didn't need to keep adding on as many special correction factors each time the instruments improved. So now we're doing relativity and quantum mechanics, and they are just means of calculation. Relativity doesn't really define an interpretation, and Quantum Mechanics is consistent with multiple different interpretations. The different interpretations seem quite different when described in English, but the math is exactly the same. You can't chose between the multi-world interpretation and Solipsism on the basis of evidence, you need to choose on the basis of philosophical biases.
Just consider, Relativity talks about bent spaces, but in what direction is space bent? Well, that's not clear. Perhaps saying bent is just something to enable you to understand that what we're really talking about is lengths being longer in one direction than in another, but that's just gibberish. You CAN'T translate Relativity into English and have it really make sense, any more than quantum mechanics. The last one you could "pretty much" do that with was Newtonian Mechanics, and if you really think carefully about that, you also find places where you must follow the math rather than reason. Just try to think carefully about what an infinitesimal means, or an imaginary number. You can't. You're just used to them, so you slide over the places where they are incomprehensible.
FWIW, I don't understand pre-Newtonian mechanics well enough, but I'm rather certain that they had equally incomprehensible places. Think of Cantor's proofs, and then try to imagine what it means to paint one copy of the interval of real number red and another blue. Or Zeno's paradoxes.
I think we've pushed this "anyone can grow up to be president" thing too far.
At some point, science has to put forth something that's not only consistent but testable. Religion appears to be exempt from that troublesome requirement.
And a scientific theory can be falsified by new evidence. Religion, not so much.
As for science having a "belief system", I strongly suggest you not attempt to "disbelieve" in gravity while near the edge of a high building or in electromagnetism while sticking an uninsulated conductor into a live socket.
Pain is merely failure leaving the body
The fixation on "best" accepted theory is more about hubris than insight.
The Kolmogorov/Chaitin view is that you should believe every statement about the universe that you can't formally disprove—all at the same time— using an exponentially weighted average based on the minimum description length of each viable description (baroque theories with billions of epicycles are down-weighted by k^-1e9, where k is the mean entropy of your typical epicycle). I don't really know the math, so take that with a grain of salt, but it's at least the general idea.
The standard model is extremely cogent and concise. It will exponentially outweigh practically everything else.
The only reason this isn't used is that we pretty much never know the minimum description length for anything (there's a result where something akin to minimum description is length is formally proven to be the hardest computation definable), and we can't take the exponentially-weighted integral of all as-yet undisproven theories by any convenient method.
Any undisproven theory that comes along with the potential to be formulated as cogently (or nearly so) as the standard model should be regarded as valid until proven otherwise (either false, or irredeemably baroque).
There's no sane reason to impose incumbency politics on theory. Theory is not a vote.
Then again, all that really has to be simulated is each person's sensory perception.
Who is to say that the water in the oceans is actually made of H2O and NaCL and all kinds of microbes and other chemicals? One just needs to be convinced that any personal measurement is consistent within their universe (such as "seeing" light through a microscope, or "seeing" data on a screen connected to a spectrometer or other analysis device).
Playing Halo doesn't require that every tree leaf on the map is rendered always, but when at least one player zooms in through their scope they should see those leaves.
All my liberal friends think I'm a conservative, all my conservative friends think I'm a liberal.
As for science having a "belief system", I strongly suggest you not attempt to "disbelieve" in gravity while near the edge of a high building or in electromagnetism while sticking an uninsulated conductor into a live socket.
That's an absolutly miserable analogy. Gravity and Electricity in themselves aren't the same as the Scientific Laws describing Gravity or Electricity. People still died from falling off cliffs before Newton ever put some math to Gravity. Disbelieving that Newton has correctly described Gravity with the inverse square equations may mean you will screw up your Moon-shot, but it never made anybody jump off a cliff and hope to fly, and a lot of people built heavier than air craft that failed to fly before anyone got it right, even though they did believe in Newton's laws.
Scientific axioms are ideas such as Naturalism (meaning simply "the rejection of the Supernatural as a possible explanation for a given phenomenon", not the whole, complex philosophy we would properly call Naturalism). The principle that a theory must make testable predictions to be a part of Science is one of those Axioms of Science, as you yourself point out. You just cited a big part of Science's belief system as proof it doesn't have a belief system. A given theorem, i.e. Alfred Wegener's continental drift hypothesis, Darwin and Wallace's Natural Selection, or even Einstein's General Relativity is NOT part of the belief systems of Science - such things are the results of applying the Scientific Method, and it's the things that make up the method itself that count as belief systems. Again, the results of the method are not, and can NEVER be, themselves part of the method, in just the way Korzibski said "The map is not the territory".
I, you, or anyone else can certainly build theories that are not scientific, in that they can't be tested. Does that mean they have negative value, (in a way analogous to your "falling off a high building" analogy)?. Not at all. I can devise an idea that can't currently be tested but might be testable later (Ideas can become scientific with time, as new technologies make it possible to test things we once couldn't, but there is no Axiom of Science that explains, for all hypothesi, how to judge in advance whether a hypothesis can ever become scientific or not), I can speculate about subjects that don't fall under Strict Naturalism at all, such as what another person was thinking when they did the action I observed. I can judge various matters by a different standard than in Science (such as applying a legalstandard instead of a scientific one in determining whether someone is guilty of a crime.
None of that deserves to analogized to various forms of painful death inflicted on people for not 'believing'. Acknowledging that Science has a belief system may not count as making it into a religion, but when you conflate specific theories with the method, and then use that to threaten non-believers with painful consequences for their non-belief, you've definitely started treating Science as a religion.
Read some Kurt Gödel, Thomas S. Kuhn, and Karl Popper, please.
Who is John Cabal?