The Universe is a Hologram

[CraigS]

Ok.

I've held off on this one for a long time, because it doesn't matter how many times I read up on it … I still don't get it. So perhaps someone else could explain it … ??…

In the News a particle astrophysicist is attempting to design an experiment at Fermilab, (no less), to prove that we don't live in a Holgraphic Universe.

(Which is probably good, seeing as I haven't the foggiest on how they came up with this one).

Have fun.

Cheers

[snas (Stuart)]

If the Universe is a hologram, just call me Arnold Rimmer.

Stuart

[CraigS]

Ok Stuart .. er 'Arnold' .. you can call me EMH


but seriously, this gizmo wil be extraordinarily accurate:

"The holometer will be seven orders of magnitude more precise than any atomic clock in existence over very short time intervals."

that's more accurate than a millisecond pulsar !!



What I don't get is how they can interpret 'spacetime jitter' as 'holographic noise'. Is there a difference between the two ? How can you falsify a hologram hypothesis by measuring jitter of 1 MHz ??

This one loses me, folks !

Cheers

[Steffen]

A hologram, eh?

"Ah-ha-ha-ha-ha, you think this is the real Quaid? Ha-ha-ha!" rat-tat-tat-tat-tat "...it is!"

Cheers
Steffen.

[CraigS]

This guy, "Craig J Hogan" (the scientist referred to), is no slouch.

Just looking, he's published 21 papers leading up to this in arXiv.

The holographic theory has been around for a long while.

Leonard Susskind and even Hawking have been involved in it.

Seems to have to do with information theory.

Its a serious quantum mechanical/string theory concept, folks !

Cheers
PS: His detector is very much like LISA to detect gravitational waves. The two concepts are linked somehow.
PPS: Having said all that, I still don't get it !!

[Robh (Rob)]

An article I remembered from last year does a better job of explaining the idea.
http://www.sciencedaily.com/releases...0203130708.htm

Regards, Rob

[CraigS]

Originally Posted by Robh

An article I remembered from last year does a better job of explaining the idea.
http://www.sciencedaily.com/releases...0203130708.htm

Regards, Rob

Yes .. thanks for that Rob. Much appreciated.

I can see that this guy (Hogan) has been thinking about this for a long time. The theory behind it sounds very heavy. I still can't see how the planck scale vibrations are linked to a holographic universe. This would seem to be tied up with String Theory mathematics. I'll keep reading and looking. It seems my answers may not come without a lot of effort on my part, so it could be sometime before the penny drops for me. Oh, well .. we all have our barriers .. looks like I just met up with one of mine !

Thanks kindly for your help .. (I AM a step closer having read it. Need some thinking time, now).

Cheers & Rgds.
PS: Hey .. one of the guys commenting on Hogan's approach in your article is 'Bernard Schutz' .. the same guy who wrote Bojan's book in the 'Relativity and Pressure' thread !

[Robh (Rob)]

Craig, this is my interpretation from my limited knowledge ...

The holographic principle basically states that the information contained within a volume can be thought of as being encoded on its boundary. Thus, a 3D holographic image is formed by information via lasers at it's boundary. The description of all objects that have fallen into a black hole is contained within its event horizon. The description of the mass within the Universe is somehow inscribed on the surface of its boundary. In a given volume, there is an upper limit to the density of information it contains, so that matter cannot be subdivided infinitely many times i.e. there must be an ultimate level of fundamental particles which are bits (1 or 0) of information. The Planck scale vibrations you mentioned are indications of the bits or pixels of the Universe big picture- "the graininess of space and time".

Regards, Rob

[avandonk]

It sounds like information mapping to me. All a hologram is, is a two dimensional recording of a three dimensional object by incorporating phase information of the waves (coherent laser light) reflected from an object and interfered with a reference beam so that when the reference beam is modulated by the recording media you recreate an image of the original object in three dimensions. This is NOT the original object but a mere representation of it.

As all matter is just wave functions before they are observed and then collapse to a localised reality I cannot see what the problem is.

Reality is just self referential waves that we perceive as reality.

All your perceptions are just signals interpreted by your brain that originate in your senses. Your senses were stimulated by signals 'outside' yourself.

Where do you really begin and end?

Does reality have no strings attached?

Bert

[CraigS]

Ok. Before we get into the philosophical side of it (which IS very interesting .. but should we follow CraigS' Law: That philosophy at IIS always comes at the end of an IIS thread …?.. )

So, following on from Rob's message, I've reverted to Susskind to fill in some gaps:

Putting it all together, we have proved an amazing fact: the maximum number of bits of information that can ever fit in a region of space is equal to the number of Planckian pixels that can be packed onto the area of the boundary.

.. {if the boundary is big then we can picture it being flat}…

Everything taking place within a few light years of the boundary can be thought of as a hologram on a flat sheet of pixels ..
Of course, you shouldn't get the idea that I am talking about an ordinary hologram. Needless to say, the graininess of an ordinary sheet of photographic film is far coarser than a sheet of Planck-sized pixels.

But the biggest difference is that the hologram is quantum mechanical. It flickers and shimmers with the uncertainty of a quantum system, in order that the three dimensional image have quantum jitters. We are all made of bits moving in complicated quantum motions, but when we look closely at those bits, we find they are located out at the farthest boundaries of space.
I don't know anything less intuitive about the world than this.

the last statement is reassuring for me.

.. a big quote but I'm starting to get it.

The bits I've underlined would seem to relate it all to looking for planckian sized vibrations. One big question left is: Why should we assume its all imposed from a boundary condition ? Or is this just the paradigm of the thought experiment ? Once again Susskind says:

For me, this is the best kind of argument: a couple of basic principles, a thought experiment, and a far-reaching conclusion.

I'll have to read on to find out what the far reaching conclusion is. Hopefully, it'll be some kind of prediction .. presumably what Hogan is now testing !
Thanks for the help, everyone .. I'm getting there (I think).

Cheers

[CraigS]

Ok .. so ..

Originally Posted by CraigS

Why should we assume its all imposed from a boundary condition ?

Hubble's Law:

"The recessional velocity between any two points is proportional to the distance separating them".

So, if you look out far enough in an expanding universe, you come to a point where the galaxies are moving from you at the speed of light. Amazingly, the distance to that point never changes!
So, at a distance of ~15 billion light years, things are moving away at the speed of light, BUT also, it will always be that way, for all time!!
In every direction, galaxies move beyond the point where they recede faster than the speed of light. We are thus surrounded by a 'Cosmic Horizon'. No signals can ever reach us from beyond that horizon.

Its just like we live inside a black hole !

Apparently, the mathematics of cosmic horizons are similar to those of black holes !!

Just as black holes radiate (and allow information to escape), so do cosmic horizons. However, their radiation, (or information bits), is inward .. not outward .. and that's where the hologram bit comes in !!

Amazing ! .. Formally, this would be called the "Cosmic Principle of Complementarity" …

To an observer inside a cosmic horizon, the horizon is a hot layer composed of horizon-atoms that absorb, scramble, and then return all bits of information. To a freely moving observer who passes through the cosmic horizon, the passing is a non-event.

I think I get it, now. Absolutely amazing !! Very cool. I think I'm just about done !!

Comments welcome .. am I loosin' it ?

Cheers

[Robh (Rob)]

The whole concept is amazing!
The Universe is comprised of both separate and overlapping bubbles, each bounded by their own cosmic event horizon. Our perception of the whole Universe is confined to the sample of our own bubble universe. Intelligent life in exclusive bubble universes have no known communication line.
Effectively, we have become the centre of our own observable universe. As expansion continues and more galaxies cross the boundary of the cosmic event horizon, we will eventually end up living in a rather empty bubble.
If the cosmic event horizon is the boundary of our holographic universe, this of course means we have ever-decreasing mass in our bubble and the boundary encoding needs less memory space. So, is our bubble universe becoming more grainy with time?

Regards, Rob

[CraigS]

Hi Rob;

Boy, this is tricky. From our perspective, it seems that as galaxies move closer to the horizon, they are heated and radiate back as photons. As they cross the horizon, they don't notice anything. We must notice the photon radiation, (being directed inwards, as they pass the horizon) and it must be equal to the radiation of the escaping galaxy. It would take 15 billion years for us to notice it, though.

What do we notice after they've gone ?…
Whether the escaped galaxy is real, and how they fit into our description of the universe, has got to be unknown to us. what they left behind when they departed must linger because information is never lost (this is the laws of entropy in action).

In short, I'm not sure how would effect the graininess (??).

Cheers

[CraigS]

Back to some humour .. this one's getting way heavy (again) …

Armed with this new knowledge, I intrepidly decided to wade into the Hogan paper, foolishly thinking I might actually be able to begin to comprehend the Abstract at least !! He's the first paragraph: ….

A phenomenological calculation is presented of the effect of quantum fluctuations in the spacetime metric, or holographic noise, on interferometeric measurement of the relative positions of freely falling proof masses, in theories where spacetime satisfies covariant entropy bounds and can be represented as a quantum theory on 2+1D null surfaces. The quantum behavior of the 3+1D metric, represented by a commutation relation expressing quantum complementarity between orthogonal position operators, leads to a parameter-free prediction of quantum noise in orthogonal position measurements of freely falling masses.

Need I say more ???
(Looks like something you'd see on that snarXiv (… a test for those who think they possess PhD levels of scientific knowledge !!)

I'm glad Hogan knows what he's doing .. I wonder how many others do ?

Cheers

[cwjohn (Chris)]

Firstly, the cosmic event horizon as you have named it is not 14 billion years. It is much larger than that as clearly demonstrated in the paper by Lineweaver and Davis.

Secondly, for a moving observer this horizon would move with them, so it would not be possible that an observer pass through this horizon. They could pass through the cosmic event horizon of an observer on earth, but this would be of no significance whatsoever.

The comparison to a black hole is like comparing apples and oranges. Completely different phenomena and completely different math.

As to the proposed experiment is it any wonder that congress is reducing funding to astronomy with this sort of nonsense taking place.

Chris

[adman (Adam)]

as galaxies pass through our own cosmic horizon and go over to the 'other side' - should we be able to observe this process. Shouldn't we be able to see galaxies in the throes of disappearing from our bubble?

[Shano592 (Shane)]

Originally Posted by snas

If the Universe is a hologram, just call me Arnold Rimmer.

Stuart

No, just call ME Arnold Rimmer ... or Iron Balls, if you like. Or just plain old Ace will be fine.

[cwjohn (Chris)]

Originally Posted by adman

as galaxies pass through our own cosmic horizon and go over to the 'other side' - should we be able to observe this process. Shouldn't we be able to see galaxies in the throes of disappearing from our bubble?

Through gravitation attraction the galaxy will tend to all move at the same speed. Expansion of space will result in the galaxy moving at c relative to our timeframe at sometime in the future, thus when the photons reach us it should appear as if the entire galaxy blinks out. Of course it will be many tens of billions of years until those photons reach us, so dont hold your breath that you will see galaxies disappearing any time soon.

[CraigS]

Chris;

Some comments follow:

Originally Posted by cwjohn

Firstly, the cosmic event horizon as you have named it is not 14 billion years. It is much larger than that as clearly demonstrated in the paper by Lineweaver and Davis.

Lineweaver and Davis: “Expanding Confusion: Common Misconceptions of Cosmological Horizons and the superluminal Expansion of the Universe”, (accepted, 2003, October), paper, provides a finer detail of definition of the term ‘Cosmic Horizon’. They introduce the concept of the ‘Hubble Sphere’, the ‘Particle Horizon’ and they apply these to recessional velocites from Proper and Comoving Distance perspectives. I have no problems with adding more clarity to the definition of the ~15 billion light years I mention in my post, and refining it further, with their additions. (Ie: the ~15 billion was an estimate cited for the purposes of introducing the concept).

Originally Posted by cwjohn

Secondly, for a moving observer this horizon would move with them, so it would not be possible that an observer pass through this horizon.

.. as I mentioned in post #11.

Originally Posted by cwjohn

They could pass through the cosmic event horizon of an observer on earth, but this would be of no significance whatsoever.

It would be of no significance to the observer on the galaxy moving through the earth observer’s cosmic horizon. But the earth bound observer would most likely observe many effects as the velocity difference approaches, and exceeds, c. This topic is still hotly debated by many theorists today. I am not one of those theorists, so its not worth debating here.

Originally Posted by cwjohn

The comparison to a black hole is like comparing apples and oranges. Completely different phenomena and completely different math.

“The properties of cosmic horizons seem to be very similar to those of black holes. The mathematics of an accelerating, (exponentially expanding), universe imply that as things approach the cosmic horizon, we see them slow down … If we could send a thermometer attached to the end of a long cable, to the vicinity of the cosmic horizon, we would also discover that the temperature increases eventually approaching the infinite temperature at the horizon of a black hole … But our own (earth bound) observations, supplemented with some mathematical analysis, would indicate that they are approaching a region of incredible temperature.”

- Leonard Susskind, “The Black Hole War” , (page 439), originally published July 2008. (He’s spent a career on this stuff).

He goes on to say, from a theoretical perspective, there are other effects observed from the earth frame of reference. He says these depend on the theoretical flavour you choose .. Quantum Field Theory or String Theory.

Originally Posted by cwjohn

As to the proposed experiment is it any wonder that congress is reducing funding to astronomy with this sort of nonsense taking place.

An opinion ? .. that’s Ok .. I have ‘em too. I think its worthwhile. IMHO, regardless of the finding, the prospects of falsification or confirmation always justify the effort.

Cheers

[CraigS]

Originally Posted by cwjohn

Through gravitation attraction the galaxy will tend to all move at the same speed.

Could you please explain this ? (I'm not sure I understand where you're coming from).

Originally Posted by cwjohn

Expansion of space will result in the galaxy moving at c relative to our timeframe at sometime in the future,

Interestingly, we already see many galaxies moving at, or greater, than c. The fastest observed so far is UDFy-38135539 z = 8.55, discovered in 2010, it is the most remote object known.
It has been calculated, (as of October 2010), to have a light travel time of 13 billion years, with a present comoving distance of around 30 billion light-years. The galaxy is thus the most distant object yet identified in the universe. It may be possible to observe galaxies up to redshift of 10 with the current generation of telescopes.

(A generally accepted cosmo model shows that galaxies beyond a redshift of z=1.46, recede faster than c).

Originally Posted by cwjohn

thus when the photons reach us it should appear as if the entire galaxy blinks out. Of course it will be many tens of billions of years until those photons reach us, so dont hold your breath that you will see galaxies disappearing any time soon.

As I mentioned in my previous post, the things we should see is still up for debate amongst theorists. I’d like to keep my mind open about this one. Especially as the technology isn’t ready yet to confirm it, one way or the other.

For example, UDFy-38135539 presently looks like a ‘smudge’.

… Interesting stuff ..

Cheers
PS: The CMBR is z~1100. The recessional velocity is 3.2c. At the time of CMBR emission, the recessional velocity was 58.1c (there are some model assumptions in these figures). [Reference: Lineweaver and Davis]
Also, looks like the James Webb telescope should be able to detect galaxies more than 13.4 billion light years away (Wiki).