If you have an idea for a blog post or a new forum thread, then please contact us at forums@fqxi.org, with a summary of the topic and its source (e.g., an academic paper, conference talk, external blog post or news item).

Contests Home

Current Essay Contest

*Contest Partners: The Peter and Patricia Gruber Foundation and Scientific American*

Previous Contests

**How Should Humanity Steer the Future?**

*January 9, 2014 - August 31, 2014*

*Contest Partners: Jaan Tallinn, The Peter and Patricia Gruber Foundation, The John Templeton Foundation, and Scientific American*

read/discuss • winners

**It From Bit or Bit From It**

*March 25 - June 28, 2013*

*Contest Partners: The Gruber Foundation, J. Templeton Foundation, and Scientific American*

read/discuss • winners

**Questioning the Foundations**

Which of Our Basic Physical Assumptions Are Wrong?

*May 24 - August 31, 2012*

*Contest Partners: The Peter and Patricia Gruber Foundation, SubMeta, and Scientific American*

read/discuss • winners

**Is Reality Digital or Analog?**

*November 2010 - February 2011*

*Contest Partners: The Peter and Patricia Gruber Foundation and Scientific American*

read/discuss • winners

**What's Ultimately Possible in Physics?**

*May - October 2009*

*Contest Partners: Astrid and Bruce McWilliams*

read/discuss • winners

**The Nature of Time**

*August - December 2008*

read/discuss • winners

Current Essay Contest

Previous Contests

read/discuss • winners

read/discuss • winners

Which of Our Basic Physical Assumptions Are Wrong?

read/discuss • winners

read/discuss • winners

read/discuss • winners

read/discuss • winners

Forum Home

Introduction

Terms of Use

RSS feed | RSS help

Introduction

Terms of Use

*Posts by the author are highlighted in orange; posts by FQXi Members are highlighted in blue.*

RSS feed | RSS help

RECENT POSTS IN THIS TOPIC

**Alan Lowey**: *on* 3/19/11 at 11:03am UTC, wrote Dear Moshe, Congratulations on your dedication to the competition and your...

**Eckard Blumschein**: *on* 3/15/11 at 9:25am UTC, wrote Dear Vladimir, You might read what I replied to Georgina today in my...

**Moshe Rozali**: *on* 3/14/11 at 18:59pm UTC, wrote Thanks for your interest Yuri, I will take a look.

**Author Yuri Danoyan+**: *on* 3/12/11 at 9:21am UTC, wrote Dear Moshe Can this essay help to you for final answer? ...

**Moshe Rozali**: *on* 3/11/11 at 3:52am UTC, wrote Thanks very much Paul.

**Paul Halpern**: *on* 3/11/11 at 3:36am UTC, wrote Dear Moshe, Fascinating essay! Well-written and researched. Interesting...

**Moshe Rozali**: *on* 3/8/11 at 20:45pm UTC, wrote Thanks for your interest. I think that information is not likely to be...

**James Hoover**: *on* 3/8/11 at 19:20pm UTC, wrote Moshe, Great read. Do you think that black holes destroy information?...

RECENT FORUM POSTS

**John Merryman**: "The irony is this"expansion" is intergalactic, balancing the galactic..."
*in* Is the Past Infinite?

**Pentcho Valev**: "Eckard, "Will you please perform the quantitative check I asked you for?" ..."
*in* Call for Research...

**Eckard Blumschein**: "Georgina, It happens that a perception is at odds with a conclusion from..."
*in* Call for Research...

**Georgina Parry**: "Thanks for the link. I didn't know that Einstein was *so* fiercely..."
*in* Is the Past Infinite?

**Chuck Stark**: "As a Mathematics undergraduate with a Physics minor, this topic is near and..."
*in* Trick or Truth? — Essay...

**Anton Vrba**: "Brendan, Wow what a fantastic essay topic, congratulations! After skipping..."
*in* Trick or Truth? — Essay...

**Peter Jackson**: "John, It's clear that space can have 0 'condensed 'matter', but you've not..."
*in* Alternative Models of...

**John Prytz**: "Akinbo, Thanks for your reply but this I'm afraid is the end of the line...."
*in* Alternative Models of...

RECENT ARTICLES

*click titles to read articles*

**Quantum in Context**

An untapped resource could provide the magic needed for quantum computation—and perhaps even open the door to time travel.

**Spot the Difference to Reveal Exotic Particles**

Questioning the symmetrization postulate of quantum mechanics and the notion that electrons are indistinguishable could reveal whether hypothetical new particles exist.

**Life's Quantum Crystal Ball**

Does the ability to predict the future—perhaps with quantum help—define the fundamental difference between living and inanimate matter?

**The Quantum Truth Seeker**

Watching particles fly through an interferometer might help to unveil higher-order weirdness behind quantum theory.

**Quantifying Occam**

Is the simplest answer always the best? Connecting Medieval monks to computational complexity, using the branch of mathematics known as category theory.

RECENT FORUM POSTS

RECENT ARTICLES

An untapped resource could provide the magic needed for quantum computation—and perhaps even open the door to time travel.

Questioning the symmetrization postulate of quantum mechanics and the notion that electrons are indistinguishable could reveal whether hypothetical new particles exist.

Does the ability to predict the future—perhaps with quantum help—define the fundamental difference between living and inanimate matter?

Watching particles fly through an interferometer might help to unveil higher-order weirdness behind quantum theory.

Is the simplest answer always the best? Connecting Medieval monks to computational complexity, using the branch of mathematics known as category theory.

FQXi FORUM

December 19, 2014

CATEGORY:
FQXi Essay Contest - Is Reality Digital or Analog?
[back]

TOPIC: Continuous Spacetime From Discrete Holographic Models by Moshe Rozali [refresh]

TOPIC: Continuous Spacetime From Discrete Holographic Models by Moshe Rozali [refresh]

We argue that discrete models of quantum gravity can be reconciled with continuous spacetime, and in particular with local Lorentz invariance. The fundamental discreteness cannot be manifested merely as a short distance cutoff. Rather it is expressed in subtle and non-local correlations, of the sort which are most familiar in the context of the quantum mechanics of black holes. Hence, holography is essential in reconciling any fundamentally discrete view of the universe with our continuous and local description thereof.

I am an associate professor in the department of Physics and Astronomy at the University of British Columbia, Vancouver, Canada. I was educated in Tel-Aviv University (degrees in Mathematics and in Physics) and in the University of Texas at Austin (PhD in Physics). Before joining the faculty at UBC, I was a postdoc in the University of Illinois at Urbana-Champaign, and in Rutgers University.

You wrote: "Nevertheless, to the author it seems clear that the discreteness

associated with quantum gravitational effects has little to do with any truncation of spacetime at short distances. Rather it is manifested in global correlations between the degrees of freedom making up spacetime."

I still don't see any proof of the above statement in the essay. Is this a speculation?

Thank you.

report post as inappropriate

associated with quantum gravitational effects has little to do with any truncation of spacetime at short distances. Rather it is manifested in global correlations between the degrees of freedom making up spacetime."

I still don't see any proof of the above statement in the essay. Is this a speculation?

Thank you.

report post as inappropriate

"The difference between space and time manifests itself in the difference between boosts and rotations"

How about when this is a screw motion?

report post as inappropriate

How about when this is a screw motion?

report post as inappropriate

Shalom Moshe

Your statement below describes a model I have been thinking about for some years - a face-centered-cubic universal lattice:

You wrote: "To see the tension between this requirement [Lorentz invariant at the Planck scale] and fundamental discreteness, imagine at first the most naive possible discrete model, the assumption that our space is arranged into a cubic lattice of sides whose length is precisely lp. It is immediately clear that this statement depends on your reference frame, your friend in possession of the latest spaceship model will zoom by this lattice and will see it Lorentz contracted. The principle of relativity is clearly at odds with this very naive picture."

My short response is that the cubic lattice will not be seen from the spaceship, let alone contract because it is not itself made of matter nor does the lattice constitute a frame of reference! The lattice has no background in which it is embedded - it itself creates space, matter and everything else. My other observation about this very basic and important picture you conjured is that in such a lattice the spaceship will not move as if it were in an inertial frame, but will self-convolute as a soliton pattern leap-frogging across the field of lattice nodes, as I have outlined in my original Beautiful Universe paper on which my present fqxi paper is based.

I hope this makes sense and that it helps. Vladimir

report post as inappropriate

Your statement below describes a model I have been thinking about for some years - a face-centered-cubic universal lattice:

You wrote: "To see the tension between this requirement [Lorentz invariant at the Planck scale] and fundamental discreteness, imagine at first the most naive possible discrete model, the assumption that our space is arranged into a cubic lattice of sides whose length is precisely lp. It is immediately clear that this statement depends on your reference frame, your friend in possession of the latest spaceship model will zoom by this lattice and will see it Lorentz contracted. The principle of relativity is clearly at odds with this very naive picture."

My short response is that the cubic lattice will not be seen from the spaceship, let alone contract because it is not itself made of matter nor does the lattice constitute a frame of reference! The lattice has no background in which it is embedded - it itself creates space, matter and everything else. My other observation about this very basic and important picture you conjured is that in such a lattice the spaceship will not move as if it were in an inertial frame, but will self-convolute as a soliton pattern leap-frogging across the field of lattice nodes, as I have outlined in my original Beautiful Universe paper on which my present fqxi paper is based.

I hope this makes sense and that it helps. Vladimir

report post as inappropriate

Moshe,

Thanks for a first rate essay. Your classification of operators is a super great way to put things in perspective. And your expert explanation of Lorentz Invariance hopefully will correct a lot of misconceptions among relativity doubters (who seem to be more abundant in these forums than elsewhere)about the role of "empty space."

If you don't mind a little side observation, I like the way your philosophy and results smoothly descend from Leiniz down to contemporary researchers such as Hermann Weyl and Gregory Chaitin. Appealing to Leibniz's continuity principle, Weyl wrote in 1949*, "Only in the infinitely small may we expect to encounter the elementary and uniform laws, hence the world must be comprehended through its behavior in the infinitely small."

Good luck.

Tom

* Philosophy of Mathematics and Natural Science, Princeton.

report post as inappropriate

Thanks for a first rate essay. Your classification of operators is a super great way to put things in perspective. And your expert explanation of Lorentz Invariance hopefully will correct a lot of misconceptions among relativity doubters (who seem to be more abundant in these forums than elsewhere)about the role of "empty space."

If you don't mind a little side observation, I like the way your philosophy and results smoothly descend from Leiniz down to contemporary researchers such as Hermann Weyl and Gregory Chaitin. Appealing to Leibniz's continuity principle, Weyl wrote in 1949*, "Only in the infinitely small may we expect to encounter the elementary and uniform laws, hence the world must be comprehended through its behavior in the infinitely small."

Good luck.

Tom

* Philosophy of Mathematics and Natural Science, Princeton.

report post as inappropriate

Hello,

I the conclusion of your paper you state: "Nevertheless, to the author it seems clear that the discreteness associated with quantum gravitational effects has little to do with any truncation of spacetime at short distances. Rather it is manifested in global correlations between the degrees of freedom making up spacetime. This is the best way to avoid the tension between

Lorentz invariance and the underlying discreteness of quantum gravity."

A much more serious problem is the experimentally demonstrated non-locality in quantum mechanics. Even if you can find a mathematical way to reconcile quantum gravity with Lorentz invariance, something that it is not demonstrated in the paper, the issue still remains: relativity obeys locality and in quantum mechanics you have nonlocality confirmed by the existence of Greenberger-Horne-Zeilinger relations. These two theories cannot be reconciled physically. One must be fundamentally wrong in the sense that it is not a true theory of nature but only an instrument for making predictions. I don't know which but in my opinion, trying to invent some way to keep both is like having the cake and eating it too.

All the best.

report post as inappropriate

I the conclusion of your paper you state: "Nevertheless, to the author it seems clear that the discreteness associated with quantum gravitational effects has little to do with any truncation of spacetime at short distances. Rather it is manifested in global correlations between the degrees of freedom making up spacetime. This is the best way to avoid the tension between

Lorentz invariance and the underlying discreteness of quantum gravity."

A much more serious problem is the experimentally demonstrated non-locality in quantum mechanics. Even if you can find a mathematical way to reconcile quantum gravity with Lorentz invariance, something that it is not demonstrated in the paper, the issue still remains: relativity obeys locality and in quantum mechanics you have nonlocality confirmed by the existence of Greenberger-Horne-Zeilinger relations. These two theories cannot be reconciled physically. One must be fundamentally wrong in the sense that it is not a true theory of nature but only an instrument for making predictions. I don't know which but in my opinion, trying to invent some way to keep both is like having the cake and eating it too.

All the best.

report post as inappropriate

Dear Efthimios,

you said "These two theories cannot be reconciled physically. One must be fundamentally wrong in the sense that it is not a true theory of nature but only an instrument for making predictions. I don't know which but in my opinion, trying to invent some way to keep both is like having the cake and eating it too."

Yum indeed. I propose a solution in my essay. Your opinion is most welcome.

report post as inappropriate

you said "These two theories cannot be reconciled physically. One must be fundamentally wrong in the sense that it is not a true theory of nature but only an instrument for making predictions. I don't know which but in my opinion, trying to invent some way to keep both is like having the cake and eating it too."

Yum indeed. I propose a solution in my essay. Your opinion is most welcome.

report post as inappropriate

Thanks everyone for the encouragement and the interesting comments, lots of food for thought.

report post as inappropriate

report post as inappropriate

Holographic type of discreteness can prove with Holometer

http://holometer.fnal.gov/ and my non-standart idea

http://www.fqxi.org/community/forum/topic/946

report post as inappropriate

http://holometer.fnal.gov/ and my non-standart idea

http://www.fqxi.org/community/forum/topic/946

report post as inappropriate

Efthimios you said " These two theories cannot be reconciled physically. One must be fundamentally wrong in the sense that it is not a true theory of nature but only an instrument for making predictions. I don't know which but in my opinion, trying to invent some way to keep both is like having the cake and eating it too. "

That is exactly right. GR and QM both 'work' but both are based on irreconcilable assumptions. In my paper here I have traced these assumptions to two of Einstein's arbitrary and experimentally unfounded ideas: 1- the constancy of the speed of light. 2- a photon being a point object . The first worked brilliantly in SR but vastly complicated GR. The second led to the unnecessary confusions of explaining QM in terms of probability. Unless physics is restructured without these two concepts it will never be unified in a simple and direct way close to nature.

report post as inappropriate

That is exactly right. GR and QM both 'work' but both are based on irreconcilable assumptions. In my paper here I have traced these assumptions to two of Einstein's arbitrary and experimentally unfounded ideas: 1- the constancy of the speed of light. 2- a photon being a point object . The first worked brilliantly in SR but vastly complicated GR. The second led to the unnecessary confusions of explaining QM in terms of probability. Unless physics is restructured without these two concepts it will never be unified in a simple and direct way close to nature.

report post as inappropriate

Dear Vladimir,

You might read what I replied to Georgina today in my thread 833.

Regards,

Eckard

report post as inappropriate

You might read what I replied to Georgina today in my thread 833.

Regards,

Eckard

report post as inappropriate

Moshe,

Your essay was a good reading, and I gave it a good score. My essay discusses the issue of conformal completion and quotient group with AdS.

http://fqxi.org/community/forum/topic/810

Further down the discussion list is a reply of mine to Tejindar Singh, where I indicate something about noncommutative geometry in quantum gravity.

Cheers LC

report post as inappropriate

Your essay was a good reading, and I gave it a good score. My essay discusses the issue of conformal completion and quotient group with AdS.

http://fqxi.org/community/forum/topic/810

Further down the discussion list is a reply of mine to Tejindar Singh, where I indicate something about noncommutative geometry in quantum gravity.

Cheers LC

report post as inappropriate

Thanks for your interest and for your comments Lawrence, I'll take a look.

report post as inappropriate

report post as inappropriate

Moshe,

Great read.

Do you think that black holes destroy information? Some speak of holograms to explain that BHs don't.

Do you have details on this?

Jim

report post as inappropriate

Great read.

Do you think that black holes destroy information? Some speak of holograms to explain that BHs don't.

Do you have details on this?

Jim

report post as inappropriate

Thanks for your interest. I think that information is not likely to be lost, and the point of my last section is trying to learn from possible ways information can be preserved in black hole physics. For quantum mechanical black holes you'd expect discrete spectrum and finite entropy, and one might instinctively attempt to explain this fact by assuming that the horizon is made of tiny discrete bits at short distances. In this example at least, this is unlikely that things work this way, because any such discretization would be at odds with the principle of equivalence and the experience of the infalling observer. We need the holographic principle to make things work while avoiding the problems that would follow from making spacetime discrete. Maybe there is a lesson there for more general situations.

If you want to read more on the holographic principle and black hole physics, I'd recommend Lenny Susskind's books: "The Black Hole War" for non-technical exposition, and "An Introduction To Black Holes, Information And The String Theory Revolution: The Holographic Universe" for semi-technical exposition.

report post as inappropriate

If you want to read more on the holographic principle and black hole physics, I'd recommend Lenny Susskind's books: "The Black Hole War" for non-technical exposition, and "An Introduction To Black Holes, Information And The String Theory Revolution: The Holographic Universe" for semi-technical exposition.

report post as inappropriate

Dear Moshe,

Fascinating essay! Well-written and researched. Interesting speculations about the black hole energy spectrum.

Best wishes,

Paul

Paul Halpern, The Discreet Charm of the Discrete

report post as inappropriate

Fascinating essay! Well-written and researched. Interesting speculations about the black hole energy spectrum.

Best wishes,

Paul

Paul Halpern, The Discreet Charm of the Discrete

report post as inappropriate

Thanks very much Paul.

report post as inappropriate

report post as inappropriate

Dear Moshe

Can this essay help to you for final answer?

http://www.fqxi.org/community/forum/topic/946

report post as inappropriate

Can this essay help to you for final answer?

http://www.fqxi.org/community/forum/topic/946

report post as inappropriate

Dear Moshe,

Congratulations on your dedication to the competition and your much deserved top 35 placing. I have a bugging question for you, which I've also posed to all the potential prize winners btw:

Q: Coulomb's Law of electrostatics was modelled by Maxwell by mechanical means after his mathematical deductions as an added verification (thanks for that bit of info Edwin), which I highly admire. To me, this gives his equation some substance. I have a problem with the laws of gravity though, especially the mathematical representation that "every object attracts every other object equally in all directions." The 'fabric' of spacetime model of gravity doesn't lend itself to explain the law of electrostatics. Coulomb's law denotes two types of matter, one 'charged' positive and the opposite type 'charged' negative. An Archimedes screw model for the graviton can explain -both- the gravity law and the electrostatic law, whilst the 'fabric' of spacetime can't. Doesn't this by definition make the helical screw model better than than anything else that has been suggested for the mechanism of the gravity force?? Otherwise the unification of all the forces is an impossiblity imo. Do you have an opinion on my analysis at all?

Best wishes,

Alan

report post as inappropriate

Congratulations on your dedication to the competition and your much deserved top 35 placing. I have a bugging question for you, which I've also posed to all the potential prize winners btw:

Q: Coulomb's Law of electrostatics was modelled by Maxwell by mechanical means after his mathematical deductions as an added verification (thanks for that bit of info Edwin), which I highly admire. To me, this gives his equation some substance. I have a problem with the laws of gravity though, especially the mathematical representation that "every object attracts every other object equally in all directions." The 'fabric' of spacetime model of gravity doesn't lend itself to explain the law of electrostatics. Coulomb's law denotes two types of matter, one 'charged' positive and the opposite type 'charged' negative. An Archimedes screw model for the graviton can explain -both- the gravity law and the electrostatic law, whilst the 'fabric' of spacetime can't. Doesn't this by definition make the helical screw model better than than anything else that has been suggested for the mechanism of the gravity force?? Otherwise the unification of all the forces is an impossiblity imo. Do you have an opinion on my analysis at all?

Best wishes,

Alan

report post as inappropriate

Login or create account to post reply or comment.