Action-at-a-distance in Sideways EPR-Bell?

[DevilsAvocado]

You’re welcome JT.

 

[Maui]

Are dinosaurs extinct in RBW?

Indeed: You seem to prove that they are not?

How would dinosaurs go extinct in a universe in which time does not(is not supposed to) flow? You would need a completely new blockworld universe.

 

[Maui]

OK; thank you. But, help please:

Q1: What leads to Red (R) and Green (G) lights blinking on the test devices?

Q2: Why do these G/R blinkings correlate with my pressing a button on the source; as well as with each other?

Q3: Why do my hands get warmer as I hold them between the source and the test devices while someone else presses the button?

Q4: Why do photographic plates show point-like exposures when held between the source and the test devices while someone else presses the button?

Q5: Will your answers equally apply to CEPRB, which is wholly classical?

With thanks again, might I suggest that there are related questions, answers to which would help many of us understand RBW?

PS: Is there an RBW FAQ on the web?

Would that be very different to the "coincidence" which forced low entropy at the BB, which appears to have fined tuned the fundamental constants or answers the question why there is something instead of nothing?

How would you like to call it? Underlying reality? HV? ...?

 

[RUTA]

RUTA, please excuse my continuing puzzlement, but: Which experimental equipment would that be?

The two with Green lights? The two with Red lights? The two with neither? Plus combinations of same?

How does RBW account for the dynamic phenomena?

Are you saying that nothing moves from the equipment to my eye to convey these dynamics?

Thank you.

I was logging on to respond to your last post. I'll respond to this post and see if that helps ... it's shorter

The red and green lights are code for the relative locations of detector clicks. The pieces of equipment in this case would be the Source of silver atoms (or spin 1/2 particles), the magnet, the detector (see the picture on Wikipedia under Stern Gerlach Experiment, for example).

In an interferometer, the pieces of equipment would be the Source of particles, the beam splitters, the mirrors, the detectors (all these things would be "sources" in QFT, that's why I use "Source" to distinguish this form of "source" from a "sink"). To see how this experiment is modeled via spacetime symmetries (rather than "screened-off" quantum systems moving through the interferometer), see A. Bohr & O. Ulfbeck, Rev. Mod. Phys. 67, 1-35 (1995), or our presentation thereof in Stuckey, W.M., Silberstein, M., Cifone, M.: Reconciling spacetime and the quantum: Relational Blockworld and the quantum liar paradox. Foundations of Physics 38(4), 348-383 (2008), quant-ph/0510090.

In RBW, dynamic phenomena only appear statistically, i.e., at what is generally called the "classical level." At the most fundamental level, the "rule" is not dynamic -- like Huw's Helsinki model -- it's a criterion for building graphs. If you follow the "self consistency criterion" for building graphs at the fundamental level, then you get a partition function for the distribution of relations comprising the experiment, so you recover classical physics as a statistical limit. So, per RBW, when one is doing a "quantum" experiment, one is probing the most fundamental composition, i.e., relations, of the experimental equipment (again, there isn't any"thing" moving through the equipment). See Fig 1-4 of 0908.4348 (under review at FoP).

To answer your last question, photons are not "things," since there is no context when they're not "screened off." So, yes, no"thing" moves from the equipment to your eyes in order for you to see the equipment -- there are just relations that co-define you and the equipment. This is not a new idea, here are a couple quotes along the same lines:

"Photons are clicks in photon detectors" -- attributed to Zeilinger, arXiv quant-ph/0505187v4

"The droplets in the cloud chamber form a track that vividly conveys the image of a particle passing through the chamber, but this imagined thing is a phantasm. There are no things beyond the droplets." Aage Bohr, Ben R. Mottelson & Ole Ulfbeck, Foundations of Physics, Vol. 34, No. 3, March 2004.

 

[RUTA]

I’ve localized the problem – it’s "lost in translation" related... It’s the two words ontology and formalism, which messes up things for me. Please correct me if I’m wrong:

Ontology: the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations.

Meaning that, this is the way we as human beings perceive the world around us. We see the laser beam, and the polarizer, and the measuring electronics, and the clock. Now, if our consciousness is in anyway "involved" in the outcome of EPR-Bell experiments, we’re going to have a darned hard time solving this enigma, by just using the reality as we perceive it.​

I have very naive, parochial definitions for philosophical terms (pretty typical of physicists), but I would say something doesn't have to be "perceived" to possesses ontological status, e.g., atoms, bacteria, and viruses, are generally ascribed ontic status even though we can't directly perceive them.

Formalism: describes an emphasis on form over content or meaning, and mathematics is no more than the symbols written down by the mathematician, which is based on logic and a few elementary rules alone.

Meaning that, we can write a computer program called the Game of Life, having a 2D grid of square cells and just 4 basic rules for survival. The name of the game doesn’t necessary mean it’s related to reality and the real life of living beings. The game and the rules is all there is, and we are able to do scientific research using axioms and theorems, viable in the current formalism.

When I say "formalism" I mean the mathematical formalism of the physics, which must correspond to reality (per experiment) by definition. Your example isn't "physics," per my definition, but it "looks like" or "mimics" experience, so one might be tempted to explore it as physics, i.e., establish a corresponding experimental program.

I interpret the above and EPW as – Mathematically there is S symmetry between EPRB & SEPRB. In the real world with measuring apparatus, the S symmetry is broken.

Then the question remains, what is correct, mathematics or our senses and consciousness?

I have no idea... but I suspect that the "ordinary-life-of-a-brain" would never have discovered QM or Spacetime curvature, without formalism and mathematics...

Correct...?:uhh:?

I wouldn't use the term "broken symmetry" in EPW, but maybe there is some sense in which it's applicable.

Generally, we favor the experimental evidence over the theoretical predictions, but that doesn't always prove a good discriminator, e.g., Einstein didn't believe GR's prediction of the expansion of universe because it didn't match the astronomical observations of the time. Personally, I would not reject experimental data, although I would consider rejecting the analysis of experimental data. In other words, I might advocate a different analysis using the raw data, but I would not attack the raw data itself unless I (or someone I trusted) replicated the experiment and obtained different raw data altogether.​

 

[Gordon Watson]

Would that be very different to the "coincidence" which forced low entropy at the BB, which appears to have fined tuned the fundamental constants or answers the question why there is something instead of nothing?

How would you like to call it? Underlying reality? HV? ...?

I believe that:

1. Einstein was a proponent of hidden variables (HVs).

2. d'Espagnat referred to "veiled reality".

3. Bell hoped for a simple constructive model of reality.

4. I am as a beginner in their camp.

5. Bell was wrong to assert that the values of sensitive HVs are revealed by observation. It is their equivalence classes that are revealed.

6. The values of sensitive HVs remain hidden; that's why "hidden variables" is good nomenclature.

 

[DevilsAvocado]

... To answer your last question, photons are not "things," since there is no context when they're not "screened off." So, yes, no"thing" moves from the equipment to your eyes in order for you to see the equipment -- there are just relations that co-define you and the equipment. This is not a new idea, here are a couple quotes along the same lines:

"Photons are clicks in photon detectors" -- attributed to Zeilinger, arXiv quant-ph/0505187v4

"The droplets in the cloud chamber form a track that vividly conveys the image of a particle passing through the chamber, but this imagined thing is a phantasm. There are no things beyond the droplets." Aage Bohr, Ben R. Mottelson & Ole Ulfbeck, Foundations of Physics, Vol. 34, No. 3, March 2004.

This is interesting. Albert Einstein stated shortly before he died:

"Nowadays every Tom, Dick and Harry thinks he knows what a photon is, but he is mistaken".​

...

 

[DevilsAvocado]

... atoms ... are generally ascribed ontic status even though we can't directly perceive them.

This is what excite me and almost drives me crazy at the same time!

Atoms have a status of real or factual existence. And we can see them thru scanning tunneling microscope!

The positions of the individual Gold atoms
composing the surface are visible.

BUT! Atoms could not be atoms without the "imaginary" components electrons and photons (and quarks)!? The real needs the "unreal" to become existent??

It drives me nuts...

When I say "formalism" I mean the mathematical formalism of the physics, which must correspond to reality (per experiment) by definition.

I knew I missed something very important, again!

Thanks for explaining. Though, there are 4 words that (probably) brings me back to square one; "must correspond to reality".

If the formalism of EPRB & SEPRB "must correspond to reality", I cannot for my life see how the shared S symmetry could survive. There is an option for "something" to travel from C -> B at the speed of light, but this option is not available at A -> B, in the corresponding reality (sorry for repeating myself).

The only way out of this afaict, is that the "state" between the source and polarizer is "unknown" and "open" for mathematical symmetry in QED...

But I still have problems when things "pop out" into a corresponding reality... click...

Generally, we favor the experimental evidence over the theoretical predictions, but that doesn't always prove a good discriminator, e.g., Einstein didn't believe GR's prediction of the expansion of universe because it didn't match the astronomical observations of the time. Personally, I would not reject experimental data, although I would consider rejecting the analysis of experimental data. In other words, I might advocate a different analysis using the raw data, but I would not attack the raw data itself unless I (or someone I trusted) replicated the experiment and obtained different raw data altogether.

That would be my definition of an excellent scientist!

(Contrary to some shocking examples we seen discussing EPR in other threads... )

 

[RUTA]

How would dinosaurs go extinct in a universe in which time does not(is not supposed to) flow? You would need a completely new blockworld universe.

You can tell dynamical stories with a blockworld, but the 4D perspective is nicely described by this Geroch quote:

There is no dynamics within space-time itself: nothing ever moves therein; nothing happens; nothing changes. In particular, one does not think of particles as moving through space-time, or as following along their world-lines. Rather, particles are just in space-time, once and for all, and the world-line represents, all at once, the complete life history of the particle.

Geroch, R.: General Relativity from A to B. University of Chicago Press, Chicago (1978), pp 20-21.

If you're open to the 4D perspective, then adynamical approaches to physics are not so shocking. This is what Huw suggests in his "Toy Models" paper and what we're claiming in RBW, i.e., the fundamental rule of physics concerns "4D patterns" rather than dynamics.

 

[RUTA]

Atoms have a status of real or factual existence. And we can see them thru scanning tunneling microscope!

BUT! Atoms could not be atoms without the "imaginary" components electrons and photons (and quarks)!? The real needs the "unreal" to become existent??

This confusion is always generated by statements like "atoms and photons don't exist." Zeilinger has created interference patterns with large molecules (buckyballs, I think) and there's nothing in QM that says you can't get interference patterns using even bigger objects. So, do molecules not exist? Where is the "cut off?"

The "picture of atoms" you showed was generated by millions of photons per second. The belief is that the atoms are "there" whether we excite them or not. That's the source of the confusion. In the RBW "relational" view, or Bohr et al's "symmetry" view, or Zeilinger's "measurement" view, if you strip away the relations/symmetries/measurements, you lose everything. In the atomic view, you still have the atom "sitting there in space," it's just not interacting with anything, i.e., it's "screened off." Once you decide to construct "things," like the atoms in your picture, from relations/symmetries/measurements, rather than smaller "things," e.g., quarks and electrons, then you understand clearly that the atoms in your picture slowly disappear as you gradually reduce the number of relations/symmetries/measurements ("photons" in the language of "things") used to "see them." In other words, the relations (aka "photons" in "things" talk) don't allow you to "see the atoms," the relations "construct the atoms." So, given millions of photons per second, you're well into the classical regime, thus your "picture." This view makes it clear how the dynamical/causal classical reality of interacting "things" might obtain statistically from a more fundamental, adynamical reality of relations/symmetries/measurements (a la the Figure from our arXiv paper you posted earlier).

BTW, thanks for that post. I haven't had time to answer all the questions posted here for me, so I was glad you helped me out The answer was good.

 

[DevilsAvocado]

The "picture of atoms" you showed was generated by millions of photons per second. The belief is that the atoms are "there" whether we excite them or not. That's the source of the confusion. In the RBW "relational" view, or Bohr et al's "symmetry" view, or Zeilinger's "measurement" view, if you strip away the relations/symmetries/measurements, you lose everything. In the atomic view, you still have the atom "sitting there in space," it's just not interacting with anything, i.e., it's "screened off." Once you decide to construct "things," like the atoms in your picture, from relations/symmetries/measurements, rather than smaller "things," e.g., quarks and electrons, then you understand clearly that the atoms in your picture slowly disappear as you gradually reduce the number of relations/symmetries/measurements ("photons" in the language of "things") used to "see them." In other words, the relations (aka "photons" in "things" talk) don't allow you to "see the atoms," the relations "construct the atoms." So, given millions of photons per second, you're well into the classical regime, thus your "picture." This view makes it clear how the dynamical/causal classical reality of interacting "things" might obtain statistically from a more fundamental, adynamical reality of relations/symmetries/measurements (a la the Figure from our arXiv paper you posted earlier).

YES! FINALLY! I THINK I’VE GOT IT! Many many many thanks RUTA!

It’s just sweet when the brain "clicks"! This is how it must be: To make an observation of QM objects, we must "bombard" it massively on the microscopic scale, so massively that we "transcend" to the macroscopic scale. It’s almost (in the macroscopic world) like we were forced to put "heavy fire" on a building to be able to observe it (and destroying the finer "stucco properties" at the same time ). Right?

Now something else strikes me... about good old Einstein:

"Do you really think the moon isn't there if you aren't looking at it?"​

I’m not the man to settle this question, but, in respect of what you just explained – it’s not "the moon" we are looking at, it’s trillions of photons, emitted from the Sun, reflected from the surface of the Moon, finally hitting our retina, to form a picture of the macroscopic object "the moon" in our brain.

Of course, one could build a "private rocket", and put a blindfold on, and smash ones forehead into the surface of the Moon, to exclude the photons in a slightly more "brutal observation"...

Never the less, this "observation" would "transcend" to the "macroscopic heavy fire" level as well!

(and the "rocket option" is of course not available for atoms)

This is just so interesting! I think I’ve learned something very important today, in the "screen-off-business"! Thanks again RUTA!

BTW, thanks for that post. I haven't had time to answer all the questions posted here for me, so I was glad you helped me out The answer was good.

It’s my pleasure if I can help in any way (not just ask "confused" questions )! Glad it was accurate!

 

[Maui]

YES! FINALLY! I THINK I’VE GOT IT! Many many many thanks RUTA!

It’s just sweet when the brain "clicks"! This is how it must be: To make an observation of QM objects, we must "bombard" it massively on the microscopic scale, so massively that we "transcend" to the macroscopic scale. It’s almost (in the macroscopic world) like we were forced to put "heavy fire" on a building to be able to observe it (and destroying the finer "stucco properties" at the same time ). Right?

Yes. The most consistent picture is that solid matter is the result of billions of 'measurements' per second, not of solid objects existing in spacetime.

You can tell dynamical stories with a blockworld, but the 4D perspective is nicely described by this Geroch quote:

There is no dynamics within space-time itself: nothing ever moves therein; nothing happens; nothing changes. In particular, one does not think of particles as moving through space-time, or as following along their world-lines. Rather, particles are just in space-time, once and for all, and the world-line represents, all at once, the complete life history of the particle.

Geroch, R.: General Relativity from A to B. University of Chicago Press, Chicago (1978), pp 20-21.

If you're open to the 4D perspective, then adynamical approaches to physics are not so shocking. This is what Huw suggests in his "Toy Models" paper and what we're claiming in RBW, i.e., the fundamental rule of physics concerns "4D patterns" rather than dynamics.

The worldline 'moves' through successive measurements. I find that more consistent and easier on the brain than objects that disappear and reappear at the next Planck length(?) through a seemingly continuous motion. Zeno was a remarkable guy.

Is RBW completely deterministic?

 

[DevilsAvocado]

Yes. The most consistent picture is that solid matter is the result of billions of 'measurements' per second, not of solid objects existing in spacetime.

Yes this seems to be the case! (Except maybe for my "private-rocket-forehead-measurement"... )

 

[DevilsAvocado]

Is RBW completely deterministic?

... wonders too ...

RBW = Superdeterminism = No free will ...?

 

[RUTA]

"Is the Moon there when nobody looks?"

I would answer this question by first clarifying the phrase "nobody looks." If by this you mean simply "it doesn't interact with anything," then the answer is no, the Moon is not "there" when it's not interacting with anything (nothing special about interacting with humans). The Moon is not anywhere in this case -- it doesn't exist because it is defined by interactions. No interactions, no Moon. [We prefer the word "relations" to "interactions," because the latter is too dynamical; in RBW the fundamental law deals with links on graphs, and not all links correspond to "interactions." But, speaking in terms of interactions is a helpful first step.]

"The most consistent picture is that solid matter is the result of billions of 'measurements' per second, not of solid objects existing in spacetime."

Replace "solid objects" with "classical objects" and this is essentially what we're saying in RBW. I don't want to quibble, I just want to avoid confusion. There are small "classical objects," e.g., bacteria, viruses, etc., that some people might not think of as "solid objects."

 

[RUTA]

... wonders too ...

RBW = Superdeterminism = No free will ...?

I'm not sure how to answer this because I'm not sure what you mean by "deterministic." In the standard physics sense, I would say RBW is not deterministic because you calculate probabilities at the most fundamental level, just like in quantum physics.

 

[yoda jedi]

I’ve localized the problem – it’s "lost in translation" related... It’s the two words ontology and formalism, which messes up things for me. Please correct me if I’m wrong Ontology: the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations.

Meaning that, this is the way we as human beings perceive the world around us. We see the laser beam, and the polarizer, and the measuring electronics, and the clock. Now, if our consciousness is in anyway "involved" in the outcome of EPR-Bell experiments, we’re going to have a darned hard time solving this enigma, by just using the reality as we perceive it.

..Wrong, Ontology deals with existence.
Existence of things independently of anything (for example "human beings") a noumenon.

things "as" they exist

...Being Qua Being...

 

[Maui]

I'm not sure how to answer this because I'm not sure what you mean by "deterministic." In the standard physics sense, I would say RBW is not deterministic because you calculate probabilities at the most fundamental level, just like in quantum physics.

If you are able to correctly calculate probabilities of outcomes, then it's obviously not the most fundamental level. I thought the most fundamental level in RBW was supposed to be, how would i say it, an underlying reality or HV's(or the "aim of science is what we can say about nature, not what nature is" approach)?

There is a pretty strong tension between GR and QM with regards to the notion of determinism and hence my interest in what RBW is saying about the issue. The worldlines in GR are set in stone, assuming some weak form of realism.

 

[DevilsAvocado]

I'm not sure how to answer this because I'm not sure what you mean by "deterministic." In the standard physics sense, I would say RBW is not deterministic because you calculate probabilities at the most fundamental level, just like in quantum physics.

This is really good news! http://en.wikipedia.org/wiki/Superdeterminism" is the gloomiest theory one could think of...


P.S. Besides gloomy, it’s also maybe 'dangerous' in the hands of Creationists... I googled: [superdeterminism "relational blockworld"], and found http://www.dontveter.com/notes/hm.html" , where you are mentioned by name, quoted when quoting another physicist, plus direct linking to "Reconciling Spacetime and the Quantum: Relational Blockworld and the Quantum Liar Paradox" in the only footnote...

Ouch! Donald R. Tveter has clearly got RBW wrong! It’s not OK to be a liar! :grumpy:

:rofl:

 

[DevilsAvocado]

..Wrong, Ontology deals with existence.
Existence of things independently of anything

Thanks YJ for clarifying. I think I got the picture. Philosophy can be a slightly 'tedious' matter... causing endless discussions. If I wanted to continue along this line, I could have stated:

– There seems to be some misunderstanding. RUTA has just explained that classical objects need interaction to be existent. Please define "independently" and "anything".​

But, for god sake! I’m not asking you this question!

 

[DevilsAvocado]

"Is the Moon there when nobody looks?"

I would answer this question by first clarifying the phrase "nobody looks." If by this you mean simply "it doesn't interact with anything," then the answer is no, the Moon is not "there" when it's not interacting with anything (nothing special about interacting with humans). The Moon is not anywhere in this case -- it doesn't exist because it is defined by interactions. No interactions, no Moon. [We prefer the word "relations" to "interactions," because the latter is too dynamical; in RBW the fundamental law deals with links on graphs, and not all links correspond to "interactions." But, speaking in terms of interactions is a helpful first step.]

This is very interesting, especially when exchanging "interactions" to "relations". This must mean we are not 'simply' talking photons here, right?

Then I have a 'tricky' question for you (I hope ): I know quantum gravity is still "under development", and maybe RBW will provide the complete solution. But anyway, we take it for granted that QM objects are influenced by gravity (and spacetime bends even light/photons). Now, I would then claim that every particle in the whole universe has "relation" to "something", whether it’s the 'normal' galaxy gravity (Black holes/Dark Matter), or the repulsive gravity from Dark Energy...

Right or wrong?

 

[RUTA]

If you are able to correctly calculate probabilities of outcomes, then it's obviously not the most fundamental level. I thought the most fundamental level in RBW was supposed to be, how would i say it, an underlying reality or HV's(or the "aim of science is what we can say about nature, not what nature is" approach)?

In RBW, one computes partition functions over graphs. The graphs are constructed per the fundamental, adynamical self-consistency criterion. I'm not sure why you're claiming this can't be the most fundamental level.

There is a pretty strong tension between GR and QM with regards to the notion of determinism and hence my interest in what RBW is saying about the issue. The worldlines in GR are set in stone, assuming some weak form of realism.

If you want to know what RBW says about GR, look at Regge calculus -- it's a discrete version of GR derived from a least action principle over graphs. In Regge calculus, the least action principle leads to a set of equations in the lengths of the graphical links. One can set up and solve these equations for vacuum solutions, i.e., there are links with no stress-energy. Generally, one considers Regge calculus to be a discrete approximation to GR.

RBW suggests the following corrections:

1. RBW is "non-separable," so we are exploring an approach to Regge calculus where all links must have stress-energy. This means you can have large simplices and we believe it might lead to different analyses for galactic spectra, thereby leading to different galactic velocity profiles.

2. The fundamental level is discrete, so GR is the continuous, separable approximation to this non-separable Regge calculus.

3. A link of non-separable Regge calculus is like that shown in Fig 3 of the arXiv paper -- it's an average value of many fundamental links like those shown in Fig 2.

If we're right about how to view gravity, then quantum gravity is (relatively) trivial. We've got several computations and empirical comparisons with GR to make before we can say whether this idea is reasonable, though

 

[RUTA]

This is very interesting, especially when exchanging "interactions" to "relations". This must mean we are not 'simply' talking photons here, right?

Right.

Then I have a 'tricky' question for you (I hope ): I know quantum gravity is still "under development", and maybe RBW will provide the complete solution. But anyway, we take it for granted that QM objects are influenced by gravity (and spacetime bends even light/photons). Now, I would then claim that every particle in the whole universe has "relation" to "something", whether it’s the 'normal' galaxy gravity (Black holes/Dark Matter), or the repulsive gravity from Dark Energy...

Right or wrong?

That's the way we think about physics now -- in Newtonian gravity, every mass interacts with every other mass. In GR, it's essentially the same -- every object effects the spacetime in the immediate vicinity of its worldtube and that curved spacetime effects the spacetime in its immediate vicinity ... all the way to the worldtubes of every other object. RBW doesn't disagree, in fact because RBW is non-separable, this problem is a bit more relevant. But, we still assume the possibility of modeling systems in isolation from the rest of the universe -- an approximation that must hold if physics is to be possible.

 

[DevilsAvocado]

RBW doesn't disagree ... But, we still assume the possibility of modeling systems in isolation ...

Fascinating! But... generally in QM? Does gravity qualify as a "relation" and thus the Moon is there, as long as it has mass...??

 

[RUTA]

Fascinating! But... generally in QM? Does gravity qualify as a "relation" and thus the Moon is there, as long as it has mass...??

Certainly, gravity constitutes an "interaction"

 

[DevilsAvocado]

Certainly, gravity constitutes an "interaction"

Aha! Gotcha!

If you want to know what RBW says about GR, look at Regge calculus

I’d check out Regge calculus, and I think I’ve got a tiny "hint" what goes on in RBW. You’re using Regge calculus to produce a "Simplicial manifold" of 4D spacetime (called simplex?), right?

A 3-simplex

You break up this manifold into a "Simplicial complex" of a topological spacetime.

A simplicial 3-complex

Which is now 'open' for a "non-separable solution", right...??

I don’t understand "links" and "stress-energy"... is this a way to 'implement' gravity in RBW??

P.S. I’m a little 'surprised' how much of the vocabulary in Regge calculus is exactly the same as in my favorite (GNU GPL) program for 3D modeling and animation, http://en.wikipedia.org/wiki/Blender_(software)" ; vertices, edges, faces, triangulation and subdivision are fundamental in Blender... but maybe obvious since we are talking manifolds in both cases...

[PLAIN]http://upload.wikimedia.org/wikipedia/en/thumb/0/0b/Blender_2.54_beta_screenshot.png/700px-Blender_2.54_beta_screenshot.png

 

[RUTA]

:rofl:

This is very good! I'm sending it to colleagues!

P.S. Thanks for sending that link to the RBW reference in superdeterminism. I always thought RBW was a "God-like" idea and now I have the proof :rofl:

 

[RUTA]

You’re using Regge calculus to produce a "Simplicial manifold" of 4D spacetime (called simplex?), right?

A 3-simplex

You break up this manifold into a "Simplicial complex" of a topological spacetime.

Which is now 'open' for a "non-separable solution", right...??

I don’t understand "links" and "stress-energy"... is this a way to 'implement' gravity in RBW??

Yes. Simplices are 4D extrapolations of the 3D tetrahedron (3-simplex) you pictured, like tetrahedra are 3D extrapolations of 2D triangles. So, the simplices are bounded by tetrahedra which are bounded by triangles which are bounded by links (the silver rods bounding the red triangles in your picture of the 3-simplex). Specifying the lengths of the links uniquely determines the geometry of the graph and Regge calculus provides the equations in those link lengths. You can get as good an approximation as you like to a smooth 4D manifold by letting the simplices be as small as necessary -- just like you can approximate the surface of Earth with small enough triangles. It turns out that the stress-energy tensor (the tensor on the RHS of Einstein's equations of GR representing the momentum flux, energy density and forces in spacetime) takes its values on the links in Regge calculus. In GR it's possible to solve EE's for the metric in empty spacetime, i.e., where the stress-energy tensor is zero. The counterpart to such solutions in Regge calculus would simply be links with no associated stress-energy.

The difference to Regge calculus that we're exploring is to assume all links must have stress-energy. That means we will (at times) need links that connect distant sources, e.g., sources in two different galaxies. That means our simplices can be very large, which means spacetime isn't a smooth manifold structure. Returning to our analogy of modeling Earth's 2D surface with triangles, imagine forming the surface with continguous triangles to form a nice 2D sphere. Now, make a triangle connecting Washington D.C. with Paris and Tokyo. So much for your smooth 2D sphere. Those "manifold-violating" triangles are what we mean by "non-separable."

 

[yoda jedi]

Thanks YJ for clarifying. I think I got the picture. Philosophy can be a slightly 'tedious' matter... causing endless discussions. If I wanted to continue along this line, I could have stated:

– There seems to be some misunderstanding. RUTA has just explained that classical objects need interaction to be existent.​

then is not an ontological entity (the moon).


consequently what produces gravity ?





-----------
read:

What is ultimately possible in physics depends on foundations and philosophy
http://www.fqxi.org/data/essay-contest-files/Lynds_What_is_ultimately_po.pdf

...You could say people didn’t really think the theory was true because they had rejected the idea of truth in science. Truth in science must mean correspondence to reality, or it means nothing.
...David Deutsch



pd: and sorry the term "existence" belongs to phylosophy​

 

[Maui]

then is not an ontological entity (the moon).


consequently what produces gravity ?

We don't know ontologically what the Moon is.

Moreover, the standard "spacetime curvature" answer also falls short when you take seriosly the implications of GR, because "spacetime curvature" is also just another worldline in a 4D block universe. It cannot be a ultimate explanation of anything, ontologically.

 

[yoda jedi]

We don't know ontologically what the Moon is.

Moreover, the standard "spacetime curvature" answer also falls short when you take seriosly the implications of GR, because "spacetime curvature" is also just another worldline in a 4D block universe. It cannot be a ultimate explanation of anything, ontologically.

and who said that ?

 

[Maui]

and who said that ?

Who said what?


Your question:

then is not an ontological entity (the moon).

consequently what produces gravity ?

relating to interactions bringing the Moon into existence, must be answered within the framework of a theory of quantum gravity. I was pointing out that there isn't a particularly satisfying ontological answer what produces gravity, as GR depicts a 4D block universe.

 

[DevilsAvocado]

Yes.

Great!

Simplices are 4D extrapolations of the 3D tetrahedron (3-simplex) you pictured, like tetrahedra are 3D extrapolations of 2D triangles. So, the simplices are bounded by tetrahedra which are bounded by triangles which are bounded by links (the silver rods bounding the red triangles in your picture of the 3-simplex).

This is cool! I get this, no problem.

4D simplices –> 3D simplex –> 2D triangles –> 1D links

Specifying the lengths of the links uniquely determines the geometry of the graph and Regge calculus provides the equations in those link lengths. You can get as good an approximation as you like to a smooth 4D manifold by letting the simplices be as small as necessary -- just like you can approximate the surface of Earth with small enough triangles.

I get this also.

It turns out that the stress-energy tensor (the tensor on the RHS of Einstein's equations of GR representing the momentum flux, energy density and forces in spacetime) takes its values on the links in Regge calculus. In GR it's possible to solve EE's for the metric in empty spacetime, i.e., where the stress-energy tensor is zero. The counterpart to such solutions in Regge calculus would simply be links with no associated stress-energy.

This is very cool! I think I have a glimpse now, on how gravity works in RBW!

The difference to Regge calculus that we're exploring is to assume all links must have stress-energy. That means we will (at times) need links that connect distant sources, e.g., sources in two different galaxies. That means our simplices can be very large, which means spacetime isn't a smooth manifold structure. Returning to our analogy of modeling Earth's 2D surface with triangles, imagine forming the surface with continguous triangles to form a nice 2D sphere. Now, make a triangle connecting Washington D.C. with Paris and Tokyo. So much for your smooth 2D sphere. Those "manifold-violating" triangles are what we mean by "non-separable."

I must be missing something crucial... because I tried the "Washington–Paris–Tokyo–Triangle", and it works just fine on my computer...!?

Or do you mean that; when creating the "higher resolution" of triangles to get a smooth 2D sphere, I’m now obligated to follow the new "zigzag" pattern between the cities...?


Another question:
There’s one thing that’s hard for me, and that is to visualize 4D. Can you do this?

I’ve shown this for some pros:

[URL]http://upload.wikimedia.org/wikipedia/commons/5/55/8-cell-simple.gif[/URL]

And they say "yes it’s good" but it’s not real 4D...

Why is this so damned hard? I know we only have 3 dimensions to play with, but we can display and manipulate 3D on a 2D computer screen, right? So why can’t we display and manipulate 4D on a new 3D computer screen (that’s 'only' one dimension 'short')??

Where’s the problem? We just add time to the array and get [x, y, z, t] ...

(I know this is a stupid question , but I’m curious on your view, since you work a lot with 4D)

 

[DevilsAvocado]

This is very good! I'm sending it to colleagues!

Cool, just spread the world!

(Just wait till Sarah Palin get this news… she’s going to write a book and start a new ®evolution – "I caaaan see the world from my backyard!" :yuck:)

P.S. Thanks for sending that link to the RBW reference in superdeterminism. I always thought RBW was a "God-like" idea and now I have the proof :rofl:

On the Seventh Day Captain RUTA Created... RBW!

 

[DevilsAvocado]

pd: and sorry the term "existence" belongs to phylosophy

But, for god sake! I’m not asking you this question!