Simulations back up theory that Universe is a hologram

From Wikipedia (https://en.wikipedia.org/wiki/Holographic_principle):

"The holographic principle is a property of quantum gravity and string theories that states that the description of a volume of space can be thought of as encoded on a boundary to the region—preferably a light-like boundary like a gravitational horizon. First proposed by Gerard 't Hooft, it was given a precise string-theory interpretation by Leonard Susskind[1] who combined his ideas with previous ones of 't Hooft and Charles Thorn.[1][2] As pointed out by Raphael Bousso,[3] Thorn observed in 1978 that string theory admits a lower-dimensional description in which gravity emerges from it in what would now be called a holographic way. In a larger sense, the theory suggests that the entire universe can be seen as a two-dimensional information structure "painted" on the cosmological horizon, such that the three dimensions we observe are only an effective description at macroscopic scales and at low energies."

So the analogy is that the field inside the volume can be completely described by some function over the bounding surface of the volume, similar to how the light field captured by a hologram is projected and recorded on a flat glass or film plane. I can visualize that pretty easily, but I don't know enough to tie that to some concrete relationship to the fundamental physical forces of the universe.

1) The gist is this: Hologram is a 2D picture that encodes a 3D object using light interference.

Holographic principle states that information encodes reality into matter/energy and gravity. Basically gravity, matter and energy are sideffects of information. They are its projections.

How does this relate to hologram? Well dots that might appear like two separated dots on the 3D model, could be encoded on the 2D surface as very close. What this explains is "spooky action at a distance". We perceive two entangled electrons as being far away on a reality hologram, when in reality they are close on the fundamental 2D picture of the world.

Summary: What we perceive and measure as reality is not what reality fundamentally is.

NOTE: This is extremely layman termish and don't be too surprised if it's wrong. I last read UiaN years ago. There are also some other interesting properties, like that the any part of hologram contains whole picture of hologram but of lousier quality, etc.

2) I think Universe in a Nutshell covers most of this theory pretty well.

Yeah, this is trouble, because the common understanding of "hologram" is very different from the actual definition.

As far as I understand it (and another person has explained it better below), the indication is that the way we perceive the universe indicates that the "data" producing those perceptions is not stored in the same structures we see or detect - instead, those structures (space, mass) are sort of "implied" by a more fundamental way of "storing" that data, which we interpret secondhand because we can't perceive the original. Not sure if this is clear or accurate, but that's what I've taken away from previous articles on a holographic universe.

Others can hopefully chime in with more, but when I first was learning about it, my reaction to the word "hologram" was the same as your (1). My understanding is that when they say "hologram", they're simply meaning an n dimensional object that's encoded in n-1 dimensional space.

If you're not familiar with the basics of the Holographic Principle, start here: https://en.wikipedia.org/wiki/Holographic_principle

It's been a while since I've watched these, but IIRC these are very good videos to start with:

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

- http://www.youtube.com/watch?v=GHgi6E1ECgo

EDIT:

Key clippings from the wikipedia article-

"But Jacob Bekenstein noted that this leads to a violation of the second law of thermodynamics. If one throws a hot gas with entropy into a black hole, once it crosses the event horizon, the entropy would disappear. The random properties of the gas would no longer be seen once the black hole had absorbed the gas and settled down. The second law can only be salvaged if black holes are in fact random objects, with an enormous entropy whose increase is greater than the entropy carried by the gas.

Bekenstein argued that black holes are maximum entropy objects—that they have more entropy than anything else in the same volume. In a sphere of radius R, the entropy in a relativistic gas increases as the energy increases. The only limit is gravitational; when there is too much energy the gas collapses into a black hole. Bekenstein used this to put an upper bound on the entropy in a region of space, and the bound was proportional to the area of the region. He concluded that the black hole entropy is directly proportional to the __area__ of the event horizon."

(__'s mine)

A piece of hologram film doesn't look anything like the image, but it does have a certain distinct "look" to it. Much like the famous quote about not being able to define pr0n but I know it when I see it. Holograms have a certain "look" to them. It's what happens when you project a 3-D image onto a 2-D piece of film using all manner of weird wave interactions from a coherent source blah blah blah science talk blah.

So the terrible awful analogy is they're saying their simulation of a projection of some weirdness into normal space looks like our gravity and space and mom and apple pie.

The awful analogy being that the squigglies on holographic film are to the actual object, as their weird theory is to something vaguely like the space we live in, at least in some aspects. Take two things and there's a certain look to them and a certain transform in between and thats pretty much kinda whats going on in both cases.

This post exceeds the US recommended daily allowance of "kinda" "sorta" "mostly" so take it with a death star sized grain of salt. I'll laugh at anyone flaming me for not getting it exactly right cause this is simplified almost to not meaning much.

There is nothing else I've ever seen like Feynman's QED, not for any field of physics. It's spectacular: a "popular" level book for a general audience that doesn't tell a single fib (even by omission), and that captures the essence of the subject without delving into the math required for serious calculations. I dream of writing a book like this (about string theory or anything else).

I am not entirely sure either, what they mean by hologram. The problem is, that holographic principle ( or similar) can mean different things depending on the context. But in string theories, it is sometimes the case that lower dimensional theories can encode the same information as the full string theory. Just as illustration, if the endpoints of your strings are stuck on a two dimensional plane, but the strings can vibrate in three dimensions, then you can potentially describe the system as a theory of the endpoints in two dimensions ( and the vibration mode of the string would potentially be encoded as the type of particle), or you can describe how the strings move through three dimensions.

As for recommended reading, I liked Brian Green's The Elegant Universe.

If you can accept some tiny bits of math, I'd suggest Susskind's lectures. As close to the real thing as it can get, and almost effortless on your part.

When I see "experiment X backs up/supports/proves conclusion Y" in a headline I always mentally correct it to "experiment X does not definitively disprove conclusion Y" where X and Y are random variables operating on whatever the actual scientific experiment and conclusion respectively are.

This is pretty much one of the Ultima Thules of Mathematics. Reading about it won't make you understand it, the metaphors used in popular science are just that: simple analogies that fool the reader. If you want to understand it I'd suggest allocating 6 years of your life to be thought the foundations and move on from there.

Edited to remove a shitty snark re fractional dimensions, hence the replies.

It's going to be a real downer when we find out the universe is actually one gigantic one-dimensional Turing machine.

That's an excellent lecture, and explains a lot of these things in understandable terms. Thanks.

Basically, but the numbers are higher than 2 and 3. String theory represents the universe (the projection) as 10-dimensional, for instance.

I had the same reaction.

So they did some calculations on a black hole with and without gravity and their calculations match and now the entire universe is a hologram?

Well the important thing is that they found a way to abstract it with less dimensions than they previously did. This means that the previous theory had unnecessary redundancy, so the new theory has less cruft.

The hologram is their way of describing how they changed their way of thinking to land on this new theory. So they looked at the problem with the idea that the interactions in our universe could be a projection of the interactions in some other universe.

The breakthrough is that they found such a universe ours could be a projection of, and that universe can be described with less parameters than the previous leading theory.

The smaller a theory is, the more clear its foundational relationships will be, so the closer we are to actually understanding why things are like they are.

So previously we had a big question, why does our theory of everything require 18 (or more?) dimensions to describe the universe?

And now we have a slightly smaller question: Why does our theory of everything require 10 dimensions to describe the universe?

Consider the Anthropic principle: observations of the physical Universe must be compatible with the conscious life that observes it [1].

We don't think things are garbled because we have evolved to make 'sense' of the chaos. Perhaps everything is a garbled mess that we think we can understand.

“I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth.” ― Umberto Eco, Foucault's Pendulum

[1]: http://en.wikipedia.org/wiki/Anthropic_principle

edit: I think I went off on a tangent. The answer to your original question is that our observable universe is the thing that is being played - it is the stuff on the boundary that might be garbled.

We are the projection.

I think it's more that, it isn't a 4D world we live in, we live in a 2+ND world, and it can be mathematically simulated using ND physics, so that anyone in the 2+ND world is unable to percieve the ND information.

We can't "Play" our world because it's already being "Played".

If it turns out that the universe that we observe is just a projection from a lower dimensional space then this could radically alter the way in which we interact with that universe.

Things that seem to be coherent in our space (the things we observe - electrons, people, solar systems) may not look at all coherent in the source.

Similarly, coherent structures in the source may not be at all coherent in our space.

It might be that, by fiddling around with this theory, we could work out the mapping from the source to our space. If we could do this we could conceivably interact with this space in completely unimaginable ways.

Imagine superconducting levitation as perceived by someone from the stone age and then go up another few levels...

n.b. by 'our space' I mean the higher dimensional universe, the hologram. By 'the source' I mean the lower dimensional space that the hologram is projected from.

Strings are the projector. Except, uh, ...

Your cells would age concurrently, depending on the value of GOMAXPROCS.

The garbage collector seemed like a great idea, until now.