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dapifo
2015-Sep-12, 02:44 PM
As well we have clear what it means the Black Holes "event horizons" and its "Hawking radiations", then may we consider also as "event horizons" and its radiation ?:

- Cosmic Horizon (10 exp +30 m): Changing from Our Universe (3D space) to Beyond Our Universe to the Bulk or Cosmic Landscape. Possible cosmic microwave background (CMB) (as Susskind says) could be also considered radiations from beyond our universe boundary.


- And also Planck Horizon (10 exp - 35 m): Changing from Our Universe (3D space) to the Sub-Planck Landscape (within 6D space Calabi-Yau forms-branes-universes):

Leonard Susskind also says: ”... At the Planck scale itself we should probably add the qubit. That's the unit of information at the horizon of a black hole.”

A qubit is a quantum bit , the counterpart in quantum computing to the binary digit or bit of classical computing. Just as a bit is the basic unit of information in a classical computer, a qubit is the basic unit of information in a quantum computer.

So, Leonard Susskind compare the information on surface of a black hole (measured with qubits) with the information existing on the lower scalar levels (Planck scale), and considering it as a 2D texture (?).

This 2D “virtual” surface at Planck scale could be the boundary to be considered for the HOLOGRAM theory (!!?).... Could it be also a Event horizon ?

Both could be boundaries (event horizons) between different nD-branes.

Possible we cannot be never there as we cannot be never inside a Back hole, but yes we could receive radiations from there, and make our predictions.

Shaula
2015-Sep-12, 02:59 PM
Possible cosmic microwave background (CMB) (as Susskind says) could be also considered radiations from beyond our universe boundary.
Please provide a reference for this claim.

Also - as has been pointed out before - our universe has to be considerably larger than the 10e26m of the observable universe.


- And also Planck Horizon (10 exp - 35 m): Changing from Our Universe (3D space) to the Sub-Planck Landscape (within 6D space Calabi-Yau forms-branes-universes):
I've been over this before with you. You don't have miniature universes hidden inside CY manifolds. You are quite fundamentally misunderstanding Brane cosmology here.

Swift
2015-Sep-12, 06:08 PM
This section of the forum is for astronomy and space exploration questions with straightforward, generally accepted answers.

dapifo,

The purpose of Q&A is quoted above (from the Q&A stickies). Your post does not seem to be an appropriate post for Q&A; for one thing, these threads always turn into extended discussions. I'm moving it to Astronomy for now.

You are currently at 11 points - one more and you are banned. If you use this thread to promote ATM ideas, or advocate against mainstream theories, you will be banned.

dapifo
2015-Sep-12, 11:25 PM
Swiff, I can prove both assertions from Leonard Susskind:

1.- CMB could be also considered radiations from beyond our universe boundary... similar to the Hauking Radiation is for the event horizon of the Black Holes. The Cosmic Landscape (Leonard Susskind. 2006). I have to look for the exact words he used in the book.

2.- ”…as you proceed down the scales to the smallest things, you place strings last. That's probably not right. The string scale if it exists must be bigger than the Planck scale, although not necessarily by a lot. At the Planck scale itself we should probably add the qubit. That's the unit of information at the horizon of a black hole.” (Email of Leonard Susskind direct to me, December 2013, after reading my article 2012 also posted in the ATM).

I am just asking your point of view and opinion... nothing else !

ShinAce
2015-Sep-13, 10:52 PM
Be careful! The CMB and the polarization of the CMB are not the same thing. The B mode polarization can only be the result of a tensor field, which is gravitational. You have to attribute that to the B mode, not the whole CMB.

The only question I can find in your post is:
"This 2D “virtual” surface at Planck scale could be the boundary to be considered for the HOLOGRAM theory (!!?).... Could it be also a Event horizon ?"

While treating the event horizon of a black hole as a surface of bits each the size of a Planck length has a basis, called the holographic principle, I don't understand it as a theory. It is a principle, like ADS/CFT correspondence.

Reality Check
2015-Sep-14, 12:05 AM
Hi dapifo.
Without the exact quotes by Leonard Susskind, we cannot tell whether you have the correct context.
All we can tell you is that it is extremely unlikely that a scientist would state that the CMB is actually Hawking radiation since the CMB has fluctuations in it that cannot appear in Hawking radiation.
The CMB is not "radiations from beyond our universe boundary" in standard cosmology because in standard cosmology the universe has no boundary.
There is a cosmic event horizon (https://en.wikipedia.org/wiki/Cosmological_horizon#Event_horizon) but this is not a black hole event horizon. Black holes have a singularity that exists in the future. The universe has a singularity that exists in the past.
Is the Big Bang a black hole? (http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/universe.html)
The Universe is Not a Black Hole (http://www.preposterousuniverse.com/blog/2010/04/28/the-universe-is-not-a-black-hole/)

GarethMeredith
2015-Sep-15, 04:14 PM
Swiff, I can prove both assertions from Leonard Susskind:

1.- CMB could be also considered radiations from beyond our universe boundary... similar to the Hauking Radiation is for the event horizon of the Black Holes. The Cosmic Landscape (Leonard Susskind. 2006). I have to look for the exact words he used in the book.

2.- ”…as you proceed down the scales to the smallest things, you place strings last. That's probably not right. The string scale if it exists must be bigger than the Planck scale, although not necessarily by a lot. At the Planck scale itself we should probably add the qubit. That's the unit of information at the horizon of a black hole.” (Email of Leonard Susskind direct to me, December 2013, after reading my article 2012 also posted in the ATM).

I am just asking your point of view and opinion... nothing else !

I disagree with him. He makes arguments for multiple universes yet relies on no physical evidence for them. Some [exotic] claims have been made involving [possible] collisions between universes,

This is in fact called Ekpyrotic theory,

ShinAce
2015-Sep-15, 07:23 PM
There's no multiverse theory here. The multiverse is a different beast entirely.

His hypothesis is that the universe is larger than what we see, which is consistent with the flatness of the universe.

dapifo
2015-Sep-16, 11:32 PM
Hi dapifo.
Without the exact quotes by Leonard Susskind, we cannot tell whether you have the correct context.
All we can tell you is that it is extremely unlikely that a scientist would state that the CMB is actually Hawking radiation since the CMB has fluctuations in it that cannot appear in Hawking radiation.
The CMB is not "radiations from beyond our universe boundary" in standard cosmology because in standard cosmology the universe has no boundary.
There is a cosmic event horizon (https://en.wikipedia.org/wiki/Cosmological_horizon#Event_horizon) but this is not a black hole event horizon. Black holes have a singularity that exists in the future. The universe has a singularity that exists in the past.
Is the Big Bang a black hole? (http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/universe.html)
The Universe is Not a Black Hole (http://www.preposterousuniverse.com/blog/2010/04/28/the-universe-is-not-a-black-hole/)

Concerning point 1, (That CMB could be considered as radiations coming from[/B] beyond our universe boundary. yes I understand that LS refers to the "Observable Universe" boundary, because beyond this boundary we will not be able to see and detect any radiation (if they travel at light speed).

Sorry but I do not have with me the book ... but LS only refers to it as a possibility (?)...

[B]Concerning point 2, the sentence I type here it is absolutely exact quote of the email: ”…as you proceed down the scales to the smallest things, you place strings last. That's probably not right. The string scale if it exists must be bigger than the Planck scale, although not necessarily by a lot. At the Planck scale itself we should probably add the qubit. That's the unit of information at the horizon of a black hole.” (Email of Leonard Susskind direct to me, December 2013, after reading my article 2012 also posted in the ATM).

It says that string scale will be bigger than Planck scale...and that at Planck scale itself (as a possibility/probability/option to be considered....no proved) we should probably add the qubit.

Then I understand that LS is comparing Planck scale with black hole event horizon, where we have some type of information (2D?)... Information on the surface of a black hole can explain all the info "inside" the black hole (It seams to be similar to HOLOGRAM THEORY that propose that "quantum theory of gravity within a space-time anti-De Sitter (3D) equivalent to a theory of ordinary particles at the border (2D)."

According to John Maldacena (See article Scientific American, January-2006):

"HOLOGRAM theory states that a quantum theory of gravity within a space-time anti-De Sitter equivalent to a theory of ordinary particles at the border. Making changes in the QCD theory at the border, different theories are obtained therein: only gravitational forces or other forces such as EM, etc."

But JM says:

"Unfortunately not yet know any theory of boundary that results in an interior theory that includes just the four forces we observe in our universe. Since our universe has a defined boundary (such as having a space of anti-De Sitter and as precise holographic theory), we are not sure how a holographic theory for our universe would be defined as no appropriate place to put the hologram."


I understand that JM needs a clear Boundary (2-3D?) of the Universe to be able to extrapolate the HOLOGRAM THEORY to Our Genuine Universe (3-4D ?)... and as RCh says "in standard cosmology the universe has no boundary"...but better to say that the universe has no "external/up/above/high scale... boundary".

But following LS proposal for Planck scale, possible yes there is an "internal/down/below/small scale... (2D?) boundary at Planck scale that could contain whole info of the Universe (or , al least, of Our Universe)?... And possibly this boundary could solve the JM problem (?)

I do not know if this reasoning is OK ?

John Mendenhall
2015-Sep-17, 04:14 AM
Dapifo, you are asking us to say whether some very speculative ideas are right or wrong. The answer is they are neither.Until these idea make testable predictions, and those tests are performed and the results observed, you may as well consider their state as unknown.

Hm. Sound familiar?

Shaula
2015-Sep-17, 05:02 AM
But following LS proposal for Planck scale, possible yes there is an "internal/down/below/small scale... (2D?) boundary at Planck scale that could contain whole info of the Universe (or , al least, of Our Universe)?... And possibly this boundary could solve the JM problem (?)

I do not know if this reasoning is OK ?
No it is not. Susskind is not making some link between spacetime at the Planck scale and an event horizon - he is simply saying that the nominal size of the qubit is a Planck area and thus he would see it added in as something smaller than Strings.

I'd be very, very surprised if Susskind actually advocated the CMBR as Unruh radiation. You'd need pretty much a whole new cosmology to do that. Plus as far as I remember the effect is far too weak to explain the energy density we see and certainly would not match its cooling rate.

dapifo
2015-Sep-17, 09:57 PM
No it is not. Susskind is not making some link between spacetime at the Planck scale and an event horizon - he is simply saying that the nominal size of the qubit is a Planck area and thus he would see it added in as something smaller than Strings.

Can you explain it better ?...

Is it Ok that all the info of a Black Hole can be defined within the boundary of the Black Hole and it is equal to the Planck area (qubits) of this surface ?

Mainstream consider Planck scale as the minimum possible ... and then it seams to be a boundary ... is it OK ?


I'd be very, very surprised if Susskind actually advocated the CMBR as Unruh radiation. You'd need pretty much a whole new cosmology to do that. Plus as far as I remember the effect is far too weak to explain the energy density we see and certainly would not match its cooling rate.

Susskind is actually not advocating the CMB as radiation from the horizon Event of the Observable Universe boundary, he just make a suggestion about in his book "The Cosmic Landscape", 2005. And he proposes it very subtly as an option to be considered. If you have read the book, surely you must have read this suggestion (?)

Shaula
2015-Sep-18, 03:43 AM
Is it Ok that all the info of a Black Hole can be defined within the boundary of the Black Hole and it is equal to the Planck area (qubits) of this surface ?
The entropy of a black hole is proportional to its surface area. Thus the amount of information required to specify the microstate of the black hole is proportional to its surface area. Black holes have been shown, theoretically, to be maximally entropic and by putting together the surface area and the entropy set by the Beckstein bound you get the result that each bit could be regarded as encoded in a Planck area. Qubits require an entangled state and I am not sure it is proven that entanglement survives at this boundary.


Mainstream consider Planck scale as the minimum possible ... and then it seams to be a boundary ... is it OK ?
Not really. First off the physical significance of the Planck length is different for a number of speculative theories on how to extend the Standard Model. There is no actual proof that the Planck length is significant. Worth noting that you need to be careful here too - the Planck energy scale is not a minimum at all. You are specifically talking about lengths when you are talking about the Planck scale as a minimum. In String theory and a couple of others it is a minimum length that it makes sense to measure or that can be measured. In other theories it doesn't have this meaning.

Next up just because there is a minimum length doesn't make it a boundary in the sense that the holographic principle requires. Even in String theory where the Planck length is the smallest measurement you can make it is not the case that you just stop measuring at that scale. It is simply the point where your T type dualities kick in. In short the existence of a lower limit to measurement doesn't imply the existence of a lower dimensional surface associated with it. That lower dimensional surface is what is required by the holographic principle.


Susskind is actually not advocating the CMB as radiation from the horizon Event of the Observable Universe boundary, he just make a suggestion about in his book "The Cosmic Landscape", 2005. And he proposes it very subtly as an option to be considered. If you have read the book, surely you must have read this suggestion (?)
If he doesn't say it explicitly then I would say that it is more likely you are reading more into what is being said than is there. This option is a very bad fit to observations and doesn't fit at all with current cosmology. I have not read his book, either. Much as I respect his intellect I fall into a philosophical camp that is opposed to the way the current String theorists are using the anthropic principle. So I have little to no interest in reading popularisations about it.

dapifo
2015-Sep-19, 10:06 AM
If he doesn't say it explicitly then I would say that it is more likely you are reading more into what is being said than is there. This option is a very bad fit to observations and doesn't fit at all with current cosmology.

LS suggest it explicitly n the book as an option... Iīll try to get the book again and I will type the exact words he used. But I donīt see it so bad and far from current cosmology.

"The CMB is a cosmic background radiation that is fundamental to observational cosmology because it is the oldest light in the universe, dating to the epoch of recombination.

The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380,000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today."

Then, it is clear that CMB is a RADIATION coming from the farthest we can observe in our universe (the oldest light in Our Universe)... Then RADIATION coming from the OBSERVABLE UNIVERSE BOUNDARY.


...there is a minimum length doesn't make it a boundary in the sense that the holographic principle requires..... it doesn't imply the existence of a lower dimensional surface associated with it. That lower dimensional surface is what is required by the holographic principle.

Ok, but that it "doesīt imply", donīt mean that it cannot be possible, and that it could be an option to be considered.

Several theories consider Planck scale 2D (CDT) or 6D (Calabi-Yau shapes) and then there will be a boundary there between different dimensions (3D vs 2D or 6D).


I have not read his book, either. Much as I respect his intellect I fall into a philosophical camp that is opposed to the way the current String theorists are using the anthropic principle. So I have little to no interest in reading popularisations about it.

OK I agree that anthropic principle has beed considered too much in the last string books... but also it is clear that LS just use it to clarify that String Theory is an alternative to the anthropic principle, allowing a lot of "pocket" universes (similar or different to Our Universe) on the Cosmic Landscape, in the same way that Our Universe allows a lot of galaxies-stars-planets (similar or different to ours)...

Shaula
2015-Sep-19, 12:02 PM
LS suggest it explicitly n the book as an option... Iīll try to get the book again and I will type the exact words he used. But I donīt see it so bad and far from current cosmology.

"The CMB is a cosmic background radiation that is fundamental to observational cosmology because it is the oldest light in the universe, dating to the epoch of recombination.

The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380,000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today."

Then, it is clear that CMB is a RADIATION coming from the farthest we can observe in our universe (the oldest light in Our Universe)... Then RADIATION coming from the OBSERVABLE UNIVERSE BOUNDARY.

Ah - I think I see what you are trying to say here. But you have conflated two ideas here. Hawking radiation is a very low intensity radiation observed being emitted by an event horizon or other causal boundary. This is very different to CMB radiation coming from the boundary of our observable universe. All the CMBR quote means is that we are seeing radiation that was emitted from a position that now corresponds to the edge of the observable universe. It has to because this radiation has been travelling at the maximum speed allowed by the universe the whole time, so the photons we see now must have come from as far away as is possible to see. It is not Unruh radiation, it is radiation derived from recombination. Fundamentally different mechanisms for production.


Ok, but that it "doesīt imply", donīt mean that it cannot be possible, and that it could be an option to be considered.

Several theories consider Planck scale 2D (CDT) or 6D (Calabi-Yau shapes) and then there will be a boundary there between different dimensions (3D vs 2D or 6D).
Again, you are using a very general form of the term boundary. Not all boundaries produce Unruh type radiation.

Also the existence of a higher dimensional manifold embedded within extended dimensions does not lead to a boundary. So I don't think this is an option to consider mainly because there is no need for a boundary and even if there were one it would not meet the criteria for Unruh/Hawking type radiation.


OK I agree that anthropic principle has beed considered too much in the last string books... but also it is clear that LS just use it to clarify that String Theory is an alternative to the anthropic principle, allowing a lot of "pocket" universes (similar or different to Our Universe) on the Cosmic Landscape, in the same way that Our Universe allows a lot of galaxies-stars-planets (similar or different to ours)...
That is precisely the anthropic principle. The weak form of it at least. The universe looks like it does because if it didn't we wouldn't be observing it.

Reality Check
2015-Sep-21, 12:44 AM
Concerning point 1,
Restating what you remember from a Leonard Susskind book does not add any information, dapifo.



[U][B]Concerning point 2, the sentence I type here it is absolutely exact quote of the email:...

Yes - that is what you quoted from the email that has nothing to do with my post.
Leonard Susskind is saying that a quantum gravity theory (e.g. string theory) probably will have a unit of information called a qubit (quantum bit) at the horizon of a black hole. The scale of an event horizon is not mentioned. The horizon of a black hole is massively larger than the Planck scale. Black holes have radii measured in kilometers!



According to John Maldacena (See article Scientific American, January-2006):

No link (despite the underlining) means we have no context to these quotes. Maldacena's conjecture (https://en.wikipedia.org/wiki/AdS/CFT_correspondence) is called anti-de Sitter/conformal field theory correspondence (AdS/CFT correspondence). There is also the Holographic principle (https://en.wikipedia.org/wiki/Holographic_principle).

Reality Check
2015-Sep-21, 12:55 AM
Then, it is clear that CMB is a RADIATION coming from the farthest we can observe in our universe (the oldest light in Our Universe)... Then RADIATION coming from the OBSERVABLE UNIVERSE BOUNDARY.
This is no longer true, dapifo.
Observable universe (https://en.wikipedia.org/wiki/Observable_universe)

The surface of last scattering is the collection of points in space at the exact distance that photons from the time of photon decoupling just reach us today. These are the photons we detect today as cosmic microwave background radiation (CMBR). However, with future technology, it may be possible to observe the still older relic neutrino background, or even more distant events via gravitational waves (which also should move at the speed of light).
A paper has been published that detected the cosmic neutrino background from a second after the Big Bang (http://scienceblogs.com/startswithabang/2015/09/02/confirmed-the-last-great-prediction-of-the-big-bang-synopsis/). That is now "RADIATION coming from the farthest we can observe in our universe", i.e. "RADIATION coming from the OBSERVABLE UNIVERSE BOUNDARY".

dapifo
2015-Sep-21, 04:17 PM
No link (despite the underlining) means we have no context to these quotes. Maldacena's conjecture (https://en.wikipedia.org/wiki/AdS/CFT_correspondence) is called anti-de Sitter/conformal field theory correspondence (AdS/CFT correspondence). There is also the Holographic principle (https://en.wikipedia.org/wiki/Holographic_principle).

http://www.scientificamerican.com/article/the-illusion-of-gravity/

dapifo
2015-Sep-21, 04:26 PM
Restating what you remember from a Leonard Susskind book does not add any information, dapifo.



That is another book...but also link CMB with Black Hole radiation
https://books.google.es/books?id=ZE-yCQAAQBAJ&pg=PA44&lpg=PA44&dq=Leonard+Susskind,+CMB&source=bl&ots=fJsZzLYYQ8&sig=tGOPgx4PArti5qRcA5BgMSrkbWc&hl=es&sa=X&ved=0CEcQ6AEwBWoVChMIg9PUl8SIyAIVBw8aCh1gdQ4_#v=on epage&q=Leonard%20Susskind%2C%20CMB&f=false

dapifo
2015-Sep-21, 04:31 PM
Leonard Susskind is saying that a quantum gravity theory (e.g. string theory) probably will have a unit of information called a qubit (quantum bit) at the horizon of a black hole. The scale of an event horizon is not mentioned. The horizon of a black hole is massively larger than the Planck scale. Black holes have radii measured in kilometers!

No... L. Susskind is only saying that string length is higher than Planck length...and that at Planck scale we will find the qubit, that's the unit of information at the horizon of a black hole.

Then he is comparing the info we met on the Black Hole boundary with the info we could meet in the Planck scale !!!

Reality Check
2015-Sep-27, 11:26 PM
No... L. Susskind is only saying that string length is higher than Planck length...and that at Planck scale we will find the qubit, that's the unit of information at the horizon of a black hole.

Then he is comparing the info we met on the Black Hole boundary with the info we could meet in the Planck scale !!!
This is what you quoted:
”…as you proceed down the scales to the smallest things, you place strings last. That's probably not right. The string scale if it exists must be bigger than the Planck scale, although not necessarily by a lot. At the Planck scale itself we should probably add the qubit. That's the unit of information at the horizon of a black hole.” (Email of Leonard Susskind direct to me, December 2013, after reading my article 2012 also posted in the ATM).

That is a longer version of what I wrote: Leonard Susskind is saying that a quantum gravity theory (e.g. string theory) probably (you missed out this important word) will have a unit of information called a qubit (quantum bit) at the horizon of a black hole.
There is no comparison of "the info we met on the Black Hole boundary with the info we could meet in the Planck scale". This is a statement of what we expect to see on the event horizon only - not everywhere in the universe. The qubit only exists on an event horizon.