Physicists who propose that symmetries are emergent?

[robwilson]

This is a strawman argument. When arguing to use dynamics, topology, analysis or geometry as a tool I am specifically not arguing for complicated hypotheses over simple ones. Instead I am arguing for different perspectives which tend to have a completely different, often unconventional, foundation - i.e. unknown to most (not part of a standard curriculum).

Mathematical disciplines that are unknown to many tend also to be slightly intimidating to most, because it might seem to be more complicated than the simple alternative they already know, even if it is conceptually just as simple or even simpler than the more conventional alternative. An example of this is the exterior calculus and differential forms over standard "simpler" vector calculus and multivariable calculus learned in school.

Such "simpler" alternatives are easier in a specific context and purely perceived as generally being simpler due to them already being familiar and spoonfed from a young age, but they are in actuality not really conceptually or mathematically simpler, just different. From the broader mathematical viewpoint, they usually contain assumptions which prevent them from being directly applicable or generalizable to other theories, while the alternative formulations tend to have less or no such problems.

To paraphrase Feynman: "You can't make imperfections on a perfect thing, you need another perfect thing."


This is simply not true in general, and in fact only becomes true once the correct framework has already been identified. But that is precisely the problem we are discussing: how does one identify the correct framework in the first place? What if this framework has not yet been discovered or invented? Algebra itself being non-specific i.e. framework independent is usually of little help in this identification and selection process, especially during the beginning stages.

Discovery of novel frameworks in mathematics is an experimental process of trial and error which requires intuition, not merely computation or deduction; that only comes later once everything has already been worked out. If one is in the beginning stages of creating new mathematical frameworks or generalizing older ones (e.g. the generalization of Euclidean to non-Euclidean geometry) one is typically necessarily unable to use algebra reliably because the correct framework upon which to do algebra simply has yet to be identified.

Let me give you an example. Since this is a thread about symmetry, let's discuss the up/down left/right symmetry of spin in the standard model. Isolated from everything else, one only needs the quaternion group of order 8 to describe these symmetries. To take the classical limit of large numbers of spins, one works in the group algebra. The structure of this algebra is (in physics language) a Euclidean spacetime plus four particles. The spacetime also has a multiplication on it, which describes the macroscopic phenomenon of magnetism. Three of the particles have both left and right spins, one of them only has left spin. There is a finite symmetry that gives the weak doublets of the standard model, if we interpret the particles in the natural way as neutrino, electron, proton and neutron. So one gets all the magneto-weak structure of the standard model and classical physics simultaneously, but without mass or charge, just from the quaternion group. Pure algebra, no geometry required. One needs a bit more to get the whole standard model, but not much.

 

[Fra]

About"But one must realize that once we throw out the classical references, we loose the ground on which QM is constructed. " What "classical references" were you referring too? What ground?

The short statement is. You can not by means of usual physicist-reasoning construct QM without classical mechanics concepts. You need a classical measurment device that live in a classical spacetime. You need means to prepare and conduct measurements many times to build statistics to justify the probabllity foundation. Look at how QM was devised. The "certainty" of uncertainty relies on a classical reference.

So qm does not replace classical mechanics. It extends it and allows deaceiptions of "black boxes" I am terms of controlled interactions.

/Fredrik

 

[Auto-Didact]

Let me give you an example. Since this is a thread about symmetry, let's discuss the up/down left/right symmetry of spin in the standard model. Isolated from everything else, one only needs the quaternion group of order 8 to describe these symmetries. To take the classical limit of large numbers of spins, one works in the group algebra. The structure of this algebra is (in physics language) a Euclidean spacetime plus four particles. The spacetime also has a multiplication on it, which describes the macroscopic phenomenon of magnetism. Three of the particles have both left and right spins, one of them only has left spin. There is a finite symmetry that gives the weak doublets of the standard model, if we interpret the particles in the natural way as neutrino, electron, proton and neutron. So one gets all the magneto-weak structure of the standard model and classical physics simultaneously, but without mass or charge, just from the quaternion group. Pure algebra, no geometry required. One needs a bit more to get the whole standard model, but not much.

That is almost a complete non-sequitur. Quaternions, even if today not taught, viewed or recognized anymore as such, are dynamical geometric objects. In other words the quaternion algebra itself is a geometric invention! It is obvious that if one takes the abstract point of view of formal mathematics too seriously, the actual historical context of discovery i.e. the how, why and what of the actual invention or discovery of the mathematics itself gets drowned in the desire for abstraction.

The entire framework of the normed division algebras - of which the quaternion algebra is just an example - is an abstraction of the theory of complex analysis, which itself is arguably the strongest synthesis between all major forms of classical mathematics, more specifically pretty much the ultimate exemplar of the Cartesian unification of algebra and geometry. Every single aspect and operation of the quaternion algebra has a direct geometric interpretation; not taking this to heart because one is able to pretend that it is purely algebraic is the height of self-deception.

This is the danger of formal mathematics for students of mathematics and physics: it completely loses track of what is content, what is process, i.e. what is theory and what is method and pretends that this loss is non-problematic; for theoretical science especially theoretical and mathematical physics - this loss is an attempted suicide of the discipline. The formalist view is a new and unnatural way of doing mathematics in physics, breaking with centuries of tradition. Because it poisons physics - the greatest single source of new mathematics - this in turn poisons the well for mathematics itself.

To quote Atiyah: "Algebra is the offer made by the devil to the mathematician. The devil says: 'I will give you this powerful machine, it will answer any question you like. All you need to do is give me your soul: give up geometry and you will have this marvellous machine."

 

[jake jot]

The short statement is. You can not by means of usual physicist-reasoning construct QM without classical mechanics concepts. You need a classical measurment device that live in a classical spacetime. You need means to prepare and conduct measurements many times to build statistics to justify the probabllity foundation. Look at how QM was devised. The "certainty" of uncertainty relies on a classical reference.

So qm does not replace classical mechanics. It extends it and allows deaceiptions of "black boxes" I am terms of controlled interactions.

/Fredrik

Classical mechanics are effective theory of quantum theory and valid for their domain of applicability. But your statement is perplexing. Again quoting it

"So if the question is whether there can be things more primary than 4D spacetime or vacuum then that is possible. But one must realize that once we throw out the classical references,"

If there are things more primary than 4D spacetime and vacuum, why would that throw out the classical references? What were you referring to? The classical world is still there.

Perhaps there are many ways to frame the more primary thing.

1. like in string theory where spacetime and vacuum were created by vibrations of the strings

2. spacetime and vacuum co existing with another reality unknown to physics

3. more primary thing that pulls off spacetime and QM. I think you were referring to this? But why would it bypass the classical world, the classical word being coarse graining of the quantum world, kindly elaborate this, thanks.

 

[robwilson]

That is almost a complete non-sequitur. Quaternions, even if today not taught, viewed or recognized anymore as such, are dynamical geometric objects. In other words the quaternion algebra itself is a geometric invention! It is obvious that if one takes the abstract point of view of formal mathematics too seriously, the actual historical context of discovery i.e. the how, why and what of the actual invention or discovery of the mathematics itself gets drowned in the desire for abstraction.

The entire framework of the normed division algebras - of which the quaternion algebra is just an example - is an abstraction of the theory of complex analysis, which itself is arguably the strongest synthesis between all major forms of classical mathematics, more specifically pretty much the ultimate exemplar of the Cartesian unification of algebra and geometry. Every single aspect and operation of the quaternion algebra has a direct geometric interpretation; not taking this to heart because one is able to pretend that it is purely algebraic is the height of self-deception.

This is the danger of formal mathematics for students of mathematics and physics: it completely loses track of what is content, what is process, i.e. what is theory and what is method and pretends that this loss is non-problematic; for theoretical science especially theoretical and mathematical physics - this loss is an attempted suicide of the discipline. The formalist view is a new and unnatural way of doing mathematics in physics, breaking with centuries of tradition. Because it poisons physics - the greatest single source of new mathematics - this in turn poisons the well for mathematics itself.

To quote Atiyah: "Algebra is the offer made by the devil to the mathematician. The devil says: 'I will give you this powerful machine, it will answer any question you like. All you need to do is give me your soul: give up geometry and you will have this marvellous machine."

Ah well. You obviously "know" what is right. Certainty is the enemy of progress. Doubt is the key to discovery.

 

[bayakiv]

@ robwilson, You will not object to the fact that any associative algebra is isomorphic to some matrix algebra and the corresponding algebra of linear vector fields. Therefore, the geometry of vector fields corresponding to the algebra of a physical object is not arbitrary, but is determined by a certain dynamic principle of stability (minimality) of these fields in a suitable space. Another thing is that here we have to choose a suitable space and a suitable dynamic principle. In addition, here we are also faced with the philosophical question of the interpretation of vector fields.

 

[robwilson]

@ robwilson, You will not object to the fact that any associative algebra is isomorphic to some matrix algebra and the corresponding algebra of linear vector fields. Therefore, the geometry of vector fields corresponding to the algebra of a physical object is not arbitrary, but is determined by a certain dynamic principle of stability (minimality) of these fields in a suitable space. Another thing is that here we have to choose a suitable space and a suitable dynamic principle. In addition, here we are also faced with the philosophical question of the interpretation of vector fields.

Do I understand correctly that you are choosing a spacetime and dynamics in which to put your vector fields? In my view, spacetime is emergent, so that we do not have the luxury of choosing one.

 

[Fra]

Classical mechanics are effective theory of quantum theory and valid for their domain of applicability. But your statement is perplexing. Again quoting it

"So if the question is whether there can be things more primary than 4D spacetime or vacuum then that is possible. But one must realize that once we throw out the classical references,"

If there are things more primary than 4D spacetime and vacuum, why would that throw out the classical references? What were you referring to? The classical world is still there.

Perhaps there are many ways to frame the more primary thing.

1. like in string theory where spacetime and vacuum were created by vibrations of the strings

2. spacetime and vacuum co existing with another reality unknown to physics

3. more primary thing that pulls off spacetime and QM. I think you were referring to this? But why would it bypass the classical world, the classical word being coarse graining of the quantum world, kindly elaborate this, thanks.

Yes. The classical world is here of course, and it will continuous to be the main based of human science.

Atomic and subatomic physics are operationally defined in terms of controlled measurements in a classical macroscopic laboratory with classical detectors. From our macroscopic perpective, what is going on in the subatomic domain is not something we can directly observe. All observations are indirect, and in this respect the microstructure of matter constitutes a "black box" from the macro-perspecive. In principle the laboratory has all the requiers computations recourse to decode even the most strange information encoded in interactions with this black box system. We can also assume that the timescale of the black box dynamics are small, relative to the timescale of the observing context.

Given this assymmetry, we have developed quantum mechanics, and its formalism, and it shines! This is not what the discussion is about, and in this context the classical background is necessary. Its important to not forget that, and its not a problem per see.

The problem is when this assymmetry is no longer valid, that all conclusions, rules and laws inferred from QM does not apply! We reach these assymmetric cases when we look at cosmology in a quantum mechanical setting. One also touches opone this this assymmetry if one attempts to transform the laws of physics from the macro scale down to Planck scale, where it is not obvious wether primordal structures "see" spacetime as we know it. It might well be that the notion of the spacetime continiuum breaks down here, and that alone makes using the conventional approach to unification difficult, because the notion of the choice of background becomes ambigous (in the scaling scenario).

There are many possible abstractions one can use. Geometric abstractions have been very successful, in many domains of physics. But for these new questions, i personally find the geometric pictures to not be helpful. It doesn't mean it can't work, I just personally find them akward and outdated.

(Not to diverge into this, just to illustrate that choice of abstractions matters: I rather think in terms of interacting agents. The "environment" of one agent, is simply all the other agents. These have simiar relations as constructing principles of GR. One says, matter tells spacetime how to curve, and spacetime tells matter how to move. In this new abstration, its the agents "picture" of the environment that detemines its actions - and vice versa. But we also have that the response from the environment, puts an evolutionary pressure on the agents microstructure. This leas to a quite different "abstraction" that geometry. In this abstraction, QM as it stans corresponds to one DOMINATING agent, literally controlling the environment and boundary of a small system (say an atom), but in my abstraction here you easily see that its a special case. An important special case! but still. )

Perhaps there are many ways to frame the more primary thing.

1. like in string theory where spacetime and vacuum were created by vibrations of the strings

2. spacetime and vacuum co existing with another reality unknown to physics

3. more primary thing that pulls off spacetime and QM. I think you were referring to this? But why would it bypass the classical world, the classical word being coarse graining of the quantum world, kindly elaborate this, thanks.

Yes I think of 3, but to give ST some benefit of doubt, there IS a possible way to connect my outlined thinking with string theory. And that would be to explain the evolution process of selection of the background. That way the "string" can in principle be interpreted as the primordal observer; and that the emergent erlations of interacting strings can be shown to SELECT and single out a certain space time. This is the only reason I've kept a think thread of interested in string theory, but i have not seem much real string theoreists entertain this in a serious way, beyond generic discussions. And i think the fact that string relies on the continuum is a mistake.

/Fredrik

 

[jake jot]

Yes, spacetime is a pre-requisite for QFT as it stands.
The vacuum is the quantum description of classically "empty space" indexed by a classical spacetime. Without a solid classical background and spacetime it is difficult to justify the construction of quantum mechanics itself.

This is part of the problem.I still don't know which third theory is mentioned in your paper, but yes its possible to entertain speculative reconstructions where 4d spacetime is not a prerequisition. One idea is to consider higher dimensional worlds, where the 4D spacetime can emerge as an approximation. But this is just one idea. One can also picture NO continuous spaces at all, but instead start with more primary concepts, such as various relations or self-organisation in some large complexity continumm limie or low energy limit allows and emergence of 4D spacetime.

So if the question is wether there can be things more primary than 4D spacetime or vacuum then that is possible. But one must realize that once we thow out the classical references, we loose the ground on which QM is constructed. This is the difficult part. One can of course reconstruct QM mathematically without this ground, but then the physical basis is left out and we lost contact to reality and experiment.

/Fredrik

For reference, the third theory I'm referring to is from the following. Quoting the book "Physics meets Philosophy at the Planck Scale" about approaches to quantum gravity:

"1. Quantising General Relativity
2. Quantising a different classical theory, while still having general relativity emerge as a low- energy (large-distance) limit.
3. Having general relativity emerge as a low-energy limit of a quantum theory that is not a quantization of a classical theory
4. having both general relativity and quantum theory emerge from a theory very different from both"

I was referring to the 4th. Having both general relativity and quantum theory emerge from a theory very different from both. But is it not most accept that GR and QFT are just effective theory? I'm looking for some kind of Transformation where GR and QFT can be overidden such that the deeper theory takes over (for example, using GR there is no way to travel faster than light. But using the deeper theory. We can do much more).

 

[bayakiv]

Do I understand correctly that you are choosing a spacetime and dynamics in which to put your vector fields? In my view, spacetime is emergent, so that we do not have the luxury of choosing one.

That's right, space-time is emergent. And it is proposed to choose not space-time, but space, in which the vector field of accelerations of moving matter (in other words, Aether) is given. Look at thread Geometry of matrix Dirac algebra , where 8-dimensional Euclidean space is tried on for this role.

 

[robwilson]

That's right, space-time is emergent. And it is proposed to choose not space-time, but space, in which the vector field of accelerations of moving matter (in other words, Aether) is given. Look at thread Geometry of matrix Dirac algebra , where 8-dimensional Euclidean space is tried on for this role.

Fair enough. I've also been down that road, though in more algebraic language, and the group-theoretical perspective is discussed in my recent papers on the arxiv.

 

[bayakiv]

Fair enough. I've also been down that road, though in more algebraic language, and the group-theoretical perspective is discussed in my recent papers on the arxiv.

Wonderful! Then it remains to solve the inverse problem - to determine the shape of their vector fields by the algebraic-group properties of elementary particles. However, it is also important to know why one form is stable, and the other quickly breaks down into stable forms.

 

[Fra]

4. having both general relativity and quantum theory emerge from a theory very different from both"

I was referring to the 4th. Having both general relativity and quantum theory emerge from a theory very different from both. But is it not most accept that GR and QFT are just effective theory? I'm looking for some kind of Transformation where GR and QFT can be overidden such that the deeper theory takes over (for example, using GR there is no way to travel faster than light. But using the deeper theory. We can do much more).

This could be possible probably in several way.

LQG in small parts attempts some of this, but the approach is not radical enough and has no ambition to account for other forces. and it uncritically brings in quantum formalism in an inappropriate way imo.

My way of thinking here is if you start from building blocks of the smallest possible distinghuishable matter or agents, with certain interaction rules that only defines interactions with the environment.Then try to show that when these parts self-organize, spacetime as we know it emerge spontaneously. And along with this internal and mixe internal/external transformations endcode other forces. Interacting agents would fall in this category. Its the population and emergent evolved communication that should (as per the conjecture) encode matter contents and the laws of physics. All this presumes not 4D spacetime, nor GR in its starting poits. Instead a universal attraction, as well as locality is built into the design. It remaines however to show that the "residual universal attraction" that is left once you "shave off" the other forces, is GR in the low energy cosmo scale. In this case, gravity can also be seen as the residual entropic forces, once the internal interactions are separated. But I am not aware of much papers to direct to, where this is well develped.

/Fredrik

 

[jake jot]

This could be possible probably in several way.

LQG in small parts attempts some of this, but the approach is not radical enough and has no ambition to account for other forces. and it uncritically brings in quantum formalism in an inappropriate way imo.

My way of thinking here is if you start from building blocks of the smallest possible distinghuishable matter or agents, with certain interaction rules that only defines interactions with the environment.Then try to show that when these parts self-organize, spacetime as we know it emerge spontaneously. And along with this internal and mixe internal/external transformations endcode other forces. Interacting agents would fall in this category. Its the population and emergent evolved communication that should (as per the conjecture) encode matter contents and the laws of physics. All this presumes not 4D spacetime, nor GR in its starting poits. Instead a universal attraction, as well as locality is built into the design. It remaines however to show that the "residual universal attraction" that is left once you "shave off" the other forces, is GR in the low energy cosmo scale. In this case, gravity can also be seen as the residual entropic forces, once the internal interactions are separated. But I am not aware of much papers to direct to, where this is well develped.

/Fredrik

It's highly plausible our attempt to unify QFT and GR is like scientists at the time of Newton trying to unify space and matter when they didn't even know matter was composed of atoms.

Our physicists were so entranced by QFT and GR. Although they can explain many things. It can't explain all. I'll take the case of Hossenfelder. She critiqued many particle physicists, saying they are lost in math (title of her book). But she is also a victim. Trapped by Standard model thinking. She thought the world is all there is to it. So all most of our top physicists in the world.

I guess it's hopeless now. We may have to wait for 50 years or more when the next generations of more open minded physicists were born.

Meantime, I can't blame many physicists going into banking and other fields. As some feel it's a dead end. It is for our generation physicists.

I just hope the future would have the environment for the new generations of physicists. And not a dark future where climate change, wars, political unrests, chaos make the work of the new physicists not even possible. If so, then the physicists in this generation may be the last chance. But blind are they. Such despair, such hopelessness.

 

[bayakiv]

I just hope the future would have the environment for the new generations of physicists. And not a dark future where climate change, wars, political unrests, chaos make the work of the new physicists not even possible. If so, then the physicists in this generation may be the last chance. But blind are they. Such despair, such hopelessness.

On the contrary, scientific revolutions were often accompanied by various cataclysms.

 

[jake jot]

This could be possible probably in several way.

LQG in small parts attempts some of this, but the approach is not radical enough and has no ambition to account for other forces. and it uncritically brings in quantum formalism in an inappropriate way imo.

My way of thinking here is if you start from building blocks of the smallest possible distinghuishable matter or agents, with certain interaction rules that only defines interactions with the environment.Then try to show that when these parts self-organize, spacetime as we know it emerge spontaneously. And along with this internal and mixe internal/external transformations endcode other forces. Interacting agents would fall in this category. Its the population and emergent evolved communication that should (as per the conjecture) encode matter contents and the laws of physics. All this presumes not 4D spacetime, nor GR in its starting poits. Instead a universal attraction, as well as locality is built into the design. It remaines however to show that the "residual universal attraction" that is left once you "shave off" the other forces, is GR in the low energy cosmo scale. In this case, gravity can also be seen as the residual entropic forces, once the internal interactions are separated. But I am not aware of much papers to direct to, where this is well develped.

/Fredrik

Do you know of arxiv topics about what sits behind space and matter? I read this in old archive at PF in 2005. The subtle title is controversial so let's not discuss it, except this part only.

Like Einstein said, there is no absolute space, space is an extension of matter. Space is not primary, nor fundamental, it does not exist by itself, it is a product, just as matter and time are products. Space is dynamic, it fluctuates, it tells matter where to go and matter tells it how to curve, remember? Empty space, on the other hand, is primary. You see, there is empty space and then there is material space, a mix of ZPR and CMBR particles. Einstein' spacetime is packed full of photons, that is where Inflation, the time cone, the time arrow, the Big Bang, 'false vacuum', etc., all come from. This why we now say space is grainy.

Locality, in spacetime, is a relation. Objects are relative to other objects, not to empty space.

The field is not to be seen as the ultimate irreducible reality, empty space is. But information starts with the field... with first quantum of action.

When we think about empty space we should stay away from notions that imply motion. Terms like infinity or velocity, size or duration... are not applicable. In this realm, we must think in terms of state, not in terms of process. Process happens in spacetime.

Because the aether is not composed of parts that follow a time line and the idea of motion is not applicable, we can safely say that the aether is one. Because it is one, there is no need for motion, there is no space or distance to cover, this is where non-locality and EPR phenomena come from. State, not knowledge, is registered throughout the Universe instantaneously, Mach was right."

Source https://www.physicsforums.com/threads/the-classical-aether-vs-the-modern-vacuum.187117/page-3

Do you agree with the first sentence above that "Like Einstein said, there is no absolute space, space is an extension of matter."? This is a good punchline, space being an extension of matter. So there must be something beside space and matter (the treatise above simply calls it "empty space". To make it not a philosophical thing. I want to know how it would behave if the more primary thing has its own forces of nature that we can access within space and matter (or mathematically within spacetime and QFT). Are there arxiv theoretical physicists who dig this or none of them write such?

I know "empty space" and "aether" can be seed for mass confusion. So let's not discuss them especially the latter. But maybe refer it to "the unname". In the same thread. It concludes with

"
This notion of a primordial substance is a very old one, also known as Akasha or Brahman, and many times described as pure energy or spiritual fire. It has been anthropomorphized by man since the times of Plato and Aristotle, the Chaldeans and the Akkadians. It has been called by the names of Zeus, Jupiter, Brahma and other.

We are talking about a notion, not just a word."

Source https://www.physicsforums.com/threads/the-classical-aether-vs-the-modern-vacuum.187117/page-3

That's right. Let's not fight over a word, so just refer it as the "unname" (behind space and matter).

 

[robwilson]

Wonderful! Then it remains to solve the inverse problem - to determine the shape of their vector fields by the algebraic-group properties of elementary particles. However, it is also important to know why one form is stable, and the other quickly breaks down into stable forms.

Exactly. That is what I am working on. I'll let you know if/when I find an answer worth sharing.

 

[Auto-Didact]

Ah well. You obviously "know" what is right. Certainty is the enemy of progress. Doubt is the key to discovery.

I understand the value of doubt and uncertainty; this is exactly why I'm so skeptical of putting too much unwarranted trust in the precise formal rigorous calculational method of algebraic reasoning, which while fully exact simply may not have any actual meaning whatsoever by being wholly disembodied and disconnected from the world.

Contrast this with the intuitive, essentially uncertain and open-ended nature of geometry and dynamics which, while uncertain and sometimes even vague, does seem to be capable of embracing the world. In any case, I think we actually agree on far more than that we disagree on, even if superficially this may not seem to be so, so no harm done, carry on.

 

[Fra]

Meantime, I can't blame many physicists going into banking and other fields. As some feel it's a dead end. It is for our generation physicists.

Part of the this problem is social and political. To have the passion to work on the open problem just for the sake of intellectual stimulation is one thing. To have the wish be become a professional researcher is another thing. These two things unfortunately interfere, because even a the most passionate person needs food on the table, and the professional also need to "stay in business". This interference is quite possibly not good for the development.

(I am one of those that was told face to face by a former supervisor in power to hire or note hire that "if you want a job in this field, you must study string theory". The problem is not that there exists a person that has this view, the problem is that it is allowed and self-inforcing in the system.)

Set aside this problem, I am optimistic! But progress is slow, as long as most manhours are barking up the wrong tree (the money tree?).

/Fredrik

 

[bayakiv]

Exactly. That is what I am working on. I'll let you know if/when I find an answer worth sharing.

Some answers may require connecting dynamic principles. If you are interested in my interpretation of the principle of least action in terms of the minimality of a vector field, then look at the very beginning of the book "Mathematical Notes on the Nature of Things".

 

[jake jot]

Do you know of arxiv topics about what sits behind space and matter? I read this in old archive at PF in 2005. The subtle title is controversial so let's not discuss it, except this part only.
Do you agree with the first sentence above that "Like Einstein said, there is no absolute space, space is an extension of matter."? This is a good punchline, space being an extension of matter. So there must be something beside space and matter (the treatise above simply calls it "empty space". To make it not a philosophical thing. I want to know how it would behave if the more primary thing has its own forces of nature that we can access within space and matter (or mathematically within spacetime and QFT). Are there arxiv theoretical physicists who dig this or none of them write such?

I know "empty space" and "aether" can be seed for mass confusion. So let's not discuss them especially the latter. But maybe refer it to "the unname". In the same thread. It concludes with

"
This notion of a primordial substance is a very old one, also known as Akasha or Brahman, and many times described as pure energy or spiritual fire. It has been anthropomorphized by man since the times of Plato and Aristotle, the Chaldeans and the Akkadians. It has been called by the names of Zeus, Jupiter, Brahma and other.

We are talking about a notion, not just a word."

Source https://www.physicsforums.com/threads/the-classical-aether-vs-the-modern-vacuum.187117/page-3

That's right. Let's not fight over a word, so just refer it as the "unname" (behind space and matter).

Fra, I think the reason it is incorrect to state that space is extension of matter is the following arguments?

The Road to Relativity: The History and Meaning of Einstein's "The ... - Hanoch Gutfreund, Jürgen Renn - Google Books

quoting a tiny part of Forword to get in the mood:

Instead of thinking of space and time as a stage, on which the drama of matter unfolds, we have to imagine some ultra-modern theater, in which the stage itself becomes one of the actors.

step 1 may be put this way: There is no such thing as an empty stage without actors on it.

2. Continuing this methaphor, we can say that these space-time structures no longer form a fixed stage, on which different drames of matter and fields may be enacted: stage and actors interact. A new drama requies a new stage. Not only is the local structure (in the sense of a finite path) of space-time dynamized, but the global structure (in the sense of the entire manifold topology) is no longer given a priori. For each solution to the gravitational field equations given locally, one must work out the global topology of the maximally extended manifolds(s) compatible with these local space-time structure.

3. Finally, the stage has no properties of its own that are independent of the action. The same drama cannot be enacted on different parts of the stage: as the actors move about, they carry the stage along with them. Expressed less metaphorically, the points of the bare manifold have no inherent properties that distinguish one point from another; rather, all such distinctions depend on the presence of fields and matter. Many textbooks on general relativity still refer to these bare points as "events," incorrectly suggesting that, as in all previous physical theories, the points are physically individuated a priori, thus obscuring this truly revolutionary feature.

What textbooks made such mistakes? Could it be because it's still controversial?

It sounds very elegant. But that's not reason to think that spacetime is fundamental or just Loop Quantum Gravity.

 

[Auto-Didact]

Some answers may require connecting dynamic principles. If you are interested in my interpretation of the principle of least action in terms of the minimality of a vector field, then look at the very beginning of the book "Mathematical Notes on the Nature of Things".

To what extent does your interpretation relate to the idea that the principle of least action is mathematically speaking just a direct consequence of the generalized Stokes' theorem for one-forms on symplectic manifolds?

 

[bayakiv]

To what extent does your interpretation relate to the idea that the principle of least action is mathematically speaking just a direct consequence of the generalized Stokes' theorem for one-forms on symplectic manifolds?

As far as I understand, the space of coordinates and momenta can be combined in a symplectic manifold, and then the principle of least action can be interpreted as you said, but if the momentum is considered as a derivative value that arises as a characteristic of the motion of a singularity of a vector field in the Finsler product of two Minkowsky spaces with an inverse metric, then the principle of least action should be interpreted for differential forms in 8-dimensional space with a neutral metric.

 

[Fra]

...
Many textbooks on general relativity still refer to these bare points as "events," incorrectly suggesting that, as in all previous physical theories, the points are physically individuated a priori, thus obscuring this truly revolutionary feature.
...
What textbooks made such mistakes? Could it be because it's still controversial?

Textbooks have different levels of ambitions, some introduce things more or less quasi-axiomatically, in order to present the mathemathical machinery. Some have a historical approach.

I personally don't see a problem with the notion of an event, the bigger question is what structure and ontology you assign to the set of events. In my terminology, an event is defined relative to an observer (frame), and its INDEXED by spacetime. That in itself need not make any claim of the ontological meaning of this spacetime. Ie. it certainly need not imply its a "physical point".

In my view, the spacetime index, is implicitly encoded in the structure of the matter, and the "worldview" one piece of matter has about the remainder of the universe, is likely encoded in itself, in a hologhraphic sense (thats not to claim anything about hologhraphic principle). In this view, spacetime is implicit in the CODE of matter. What remains to be explained, is why the - a priori indepdendent codes - evolved to be consistent (and to form equivalence classes or of SR and GR).

/Fredrik

 

[Fra]

If you are interested in LQG. Check this old thread, of my own ponderings when started with Rovellis book analysing his constructing principles (before wasting time on technical deails).

https://www.physicsforums.com/threa...able-in-classical-and-quantum-gravity.220841/

/Fredrik

 

[Lord Crc]

Not sure if it was already mentioned but in Lee Smolin's latest work he explicitly says the fundamental theory has no (non-gauge) symmetries. So I assume then he means they are emergent.

He gives an overview in this recent presentation: http://pirsa.org/20110056

 

[Fra]

Not sure if it was already mentioned but in Lee Smolin's latest work he explicitly says the fundamental theory has no (non-gauge) symmetries. So I assume then he means they are emergent.

He gives an overview in this recent presentation: http://pirsa.org/20110056

Thanks for the link! I'm well aware of Smolins past reasoning on evolution of law, but i hadnt seen that recent stuff. I will look into the referencing papers and see if there's something new! Years ago, explicit proposals was not in line with what i was looking for due to not beeing radical enough, but the basic line of reasoning was in line with my thinking. Judging from the headlines it sounds interesting. I'll report back here when i had time to look at it if i find it worthwhile.

/Fredrik

 

[Lord Crc]

I will look into the referencing papers and see if there's something new!

IIRC he said the latest stuff is due to appear on arXiv, but I haven't seen it yet. But it builds on energetic causal sets and other previous work.

I'm no expert so I can't really judge it, but to me it seemed interesting and worth keeping an eye on.

 

[Fra]

The the main paper sems to be this

The dynamics of difference - Lee Smolin
"A proposal is made for a fundamental theory, in which the history of the universe is constituted of diverse views of itself. Views are attributes of events, and the theory's only be-ables; they comprise information about energy and momentum transferred to an event from its causal past. A dynamics is proposed for a universe constituted of views of events, which combines the energetic causal set dynamics with a potential energy based on a measure of the distinctiveness of the views, called the variety. As in the real ensemble formulation of quantum mechanics, quantum pure states are associated to ensembles of similar events; the quantum potential of Bohm then arises from the variety.
-- https://arxiv.org/abs/1712.04799

but it builds on ideas of other papers, on ideas of QM and energetic causal sets.

I skimmed this and I would summarize Smolins overall line of reasoning seems to be this:

- Modify/reconstruct both QM and spacetime using more fundamental abstractions.
- QM/QFT is specifically an effective theory for "subsystems" - which is also the domain of corroboration lies.
=> GR is not something one should "quantize" using the effective tools valid for particle physics. This is a conceptual mistake, which Smolin labels the cosmological fallacy.
- GR is speculated to emerge at the larger scale of interacting subsystems.
- There are no fundamental timelss laws/symmetries based on spacetime transformations (as is the case in standard model of particle physics).

At this level, this is fully in line with my thinking. But this is a massive ambition and the technical challenges are
1) what are the "more fundamental abstractions"
2) what is the kinetics and action principles that will replace tossing out timeless laws?

In Smolins current paper "The dynamics of difference", he proposes the following answers.

(1)=> the universe as consisting of "views of itself", which is represented by causal sets. Here causal order is fundamental. And thus implicitly time as index of causal order. Conceptually I associate this also to the presumed views of inside observers. For this reason he also uses the notion of beables instead of observables, so you can speak about things informally.

(2)=> assuptions from Energetic causal sets, where he while rejecting space, considers energy an momentum in 3D space as primitives along with its conservation constraints. The idea of this is the old relational tradition that spacetime view is "reconstructed" from incident energy and momentum information.

I can see how energetic causal sets is a possible way to reconstruct SPACETIME, in a way that is still somewhat conservative (not relaxing too much). But my hunch is that its not radical enough. At least as it seems in this paper, dimenstionality is put in by hand, so is momentum and energy without defining in from other first principles without circularly relying on spacetime. Perhaps I missed something in the first look though(did not check all referencing papers in depth), or maybe the causal set can be reinterpreted. The concepts of an initial set of events, having an order only. Is exactly in line with my approach but not the following steps of energetic sets. But this might lie in the pipe of furhter refinements, I have no idea.

Smolin also has a "real ensemble hypothesis" of QM, which partly resonate with hwo i see things. It means we can not make use of "fictive" ensembles or external observers doing statistics etc. Whatever statistical basis there is for QM, is has to have a physical base. I fully symphatize with this. This is also a context where evolution of law becomes natural, as its in the "population of view" that you get an emergece of consistent spacetime and probalby eventually all interactions. A possible mechanism for such emergence is simlpy put, a kind of democratic negotiation. This not only defines the common rules, it also defines what views that will not surviva. Its closely related to a evolutionary view of law.
Smolin entertains some principle of maximum variety, and principles of prescedence. All of that i can see may be hard to make sense out of, coming from the traditional paradigm. But I think its good thinking, but a lot of the details are still incomplete. So one should not prematurely judged it beacuse its not complete (and might fail of course).

/Fredrik

 

[Lord Crc]

Ah I thought he said the paper was to appear, and I only scanned the last half year.

As you say I also thought that it was cheating a bit to add momentum space by hand, so in this sense it does not feel fundamental enough. However it feels like a worthwhile pursuit, in that it may be a good step in a fruitful direction.

Though, not like my vote matters much :)

 

[jake jot]

The the main paper sems to be this

The dynamics of difference - Lee Smolin
"A proposal is made for a fundamental theory, in which the history of the universe is constituted of diverse views of itself. Views are attributes of events, and the theory's only be-ables; they comprise information about energy and momentum transferred to an event from its causal past. A dynamics is proposed for a universe constituted of views of events, which combines the energetic causal set dynamics with a potential energy based on a measure of the distinctiveness of the views, called the variety. As in the real ensemble formulation of quantum mechanics, quantum pure states are associated to ensembles of similar events; the quantum potential of Bohm then arises from the variety.
-- https://arxiv.org/abs/1712.04799

In the last paragraph of Smolin paper above are these words:

"Finally, there are implications of this proposal for foundational issues such as the measurement problem and the question of physical correlates of qualia. These will require careful consideration and are beyond he scope of this paper.".

Has Smolin written anything with regards to this "question of physical correlates of qualia"? Did he mention these in past papers or books? which one?

but it builds on ideas of other papers, on ideas of QM and energetic causal sets.

I skimmed this and I would summarize Smolins overall line of reasoning seems to be this:

- Modify/reconstruct both QM and spacetime using more fundamental abstractions.
- QM/QFT is specifically an effective theory for "subsystems" - which is also the domain of corroboration lies.
=> GR is not something one should "quantize" using the effective tools valid for particle physics. This is a conceptual mistake, which Smolin labels the cosmological fallacy.
- GR is speculated to emerge at the larger scale of interacting subsystems.
- There are no fundamental timelss laws/symmetries based on spacetime transformations (as is the case in standard model of particle physics).

At this level, this is fully in line with my thinking. But this is a massive ambition and the technical challenges are
1) what are the "more fundamental abstractions"
2) what is the kinetics and action principles that will replace tossing out timeless laws?

Didn't Smolin give any clue of the "more fundamental abstractions"? in your "
I skimmed this and I would summarize Smolins overall line of reasoning seems to be this:

- Modify/reconstruct both QM and spacetime using more fundamental abstractions."

Where in the paper did he reason about "Modify/reconstruct both QM and spacetime using more fundamental abstractions."? This makes better sense to make spacetime and QM emergent of a third theory (we discussed earlier in the thread"). Could this more fundamental abstraction be considered a third of separate theory?

Please share ideas of what Smolin thought were the more fundamental abstractions.

In Smolins current paper "The dynamics of difference", he proposes the following answers.

(1)=> the universe as consisting of "views of itself", which is represented by causal sets. Here causal order is fundamental. And thus implicitly time as index of causal order. Conceptually I associate this also to the presumed views of inside observers. For this reason he also uses the notion of beables instead of observables, so you can speak about things informally.

(2)=> assuptions from Energetic causal sets, where he while rejecting space, considers energy an momentum in 3D space as primitives along with its conservation constraints. The idea of this is the old relational tradition that spacetime view is "reconstructed" from incident energy and momentum information.

I can see how energetic causal sets is a possible way to reconstruct SPACETIME, in a way that is still somewhat conservative (not relaxing too much). But my hunch is that its not radical enough. At least as it seems in this paper, dimenstionality is put in by hand, so is momentum and energy without defining in from other first principles without circularly relying on spacetime. Perhaps I missed something in the first look though(did not check all referencing papers in depth), or maybe the causal set can be reinterpreted. The concepts of an initial set of events, having an order only. Is exactly in line with my approach but not the following steps of energetic sets. But this might lie in the pipe of furhter refinements, I have no idea.

Smolin also has a "real ensemble hypothesis" of QM, which partly resonate with hwo i see things. It means we can not make use of "fictive" ensembles or external observers doing statistics etc. Whatever statistical basis there is for QM, is has to have a physical base. I fully symphatize with this. This is also a context where evolution of law becomes natural, as its in the "population of view" that you get an emergece of consistent spacetime and probalby eventually all interactions. A possible mechanism for such emergence is simlpy put, a kind of democratic negotiation. This not only defines the common rules, it also defines what views that will not surviva. Its closely related to a evolutionary view of law.
Smolin entertains some principle of maximum variety, and principles of prescedence. All of that i can see may be hard to make sense out of, coming from the traditional paradigm. But I think its good thinking, but a lot of the details are still incomplete. So one should not prematurely judged it beacuse its not complete (and might fail of course).

/Fredrik

 

[Fra]

"Finally, there are implications of this proposal for foundational issues such as the measurement problem and the question of physical correlates of qualia. These will require careful consideration and are beyond he scope of this paper.".

Has Smolin written anything with regards to this "question of physical correlates of qualia"? Did he mention these in past papers or books? which one?

Didn't Smolin give any clue of the "more fundamental abstractions"? in your "
I skimmed this and I would summarize Smolins overall line of reasoning seems to be this:

- Modify/reconstruct both QM and spacetime using more fundamental abstractions."

Where in the paper did he reason about "Modify/reconstruct both QM and spacetime using more fundamental abstractions."? This makes better sense to make spacetime and QM emergent of a third theory (we discussed earlier in the thread"). Could this more fundamental abstraction be considered a third of separate theory?

IMO, the two questions belong together.

As my own line of reasoning is close to smolins, thinking, i find it easy to extrapolate and make sense between out what he says. But there is also a risk that my own bias risks misinterpreting his ideas. In short, all of Smolins explicit ideas are IMO not the final answers, and its also "incomplete", beeing sometimes a reconstruction "designed to give the right answers" so i can see what he means when he refers to future progress, and that the principles hold the possibility open for replacing the assumptions to increase the explanatory value (my own thinking circles in the domains which smolin skipped). I can not defend the specific examples smolins makes. IMO they are likely a first attempt to create a mathematical model, that partly implements or illustrates the possible power of the idea. But to make up your own mind, I recommend reading these papers, relating to emergence of QM

-- Precedence and freedom in quantum physics, arXiv:1205.3707v1 [quant-ph] 16 May 2012

-- Quantum mechanics and the principle of maximal variety arXiv:1506.02938v1 [quant-ph] 9 Jun 2015

But if you read it with a too critical axiomatic mindset, one likely dismisses the whole points. I consider the papers to outline and try to make simple mathematical dressings of intuitive ideas; but they can, and need improvements. Smolin for a LONG time has also advocated a new paradigm in THINKING about the nature of law, that has more in common with evolution than with classical reductionism.

/Fredrik

 

[jake jot]

IMO, the two questions belong together.

As my own line of reasoning is close to smolins, thinking, i find it easy to extrapolate and make sense between out what he says. But there is also a risk that my own bias risks misinterpreting his ideas. In short, all of Smolins explicit ideas are IMO not the final answers, and its also "incomplete", beeing sometimes a reconstruction "designed to give the right answers" so i can see what he means when he refers to future progress, and that the principles hold the possibility open for replacing the assumptions to increase the explanatory value (my own thinking circles in the domains which smolin skipped). I can not defend the specific examples smolins makes. IMO they are likely a first attempt to create a mathematical model, that partly implements or illustrates the possible power of the idea. But to make up your own mind, I recommend reading these papers, relating to emergence of QM

-- Precedence and freedom in quantum physics, arXiv:1205.3707v1 [quant-ph] 16 May 2012

-- Quantum mechanics and the principle of maximal variety arXiv:1506.02938v1 [quant-ph] 9 Jun 2015

But if you read it with a too critical axiomatic mindset, one likely dismisses the whole points. I consider the papers to outline and try to make simple mathematical dressings of intuitive ideas; but they can, and need improvements. Smolin for a LONG time has also advocated a new paradigm in THINKING about the nature of law, that has more in common with evolution than with classical reductionism.

/Fredrik

I have read the ideas in the papers already in one of his books. Who are the physicists whose ideas are opposite to that of Smolin, so I can see the distinctions of them? Because instead of laws that evolved deep in the past. Why not more complex laws of natures for the arbitrariness of the Constants of Nature? What is Smolin proposed solution to the Hierarchy Problem and Quantum Vacuum 120 magnitude of energy more than predicted by General Relativity? What do you think is the solution to it? Because unless his proposals can solve them. It's not very helpful for practical purposes.

But I'd ponder Smolin paper "The Dynamics of Difference" more since he talks like you more and more. Lol. Hope you can talk to Smolin and discuss with him about it so you'd know why he thought of certain things and his feedback for your comments on it.

 

[Lord Crc]

From the presentation I linked to, he said that so far the "intrinsic" momentum space he's been using is flat. Hence currently no GR-like results have emerged. His goal is to use a curved momentum space instead, and with that hopes to get GR out, but so far it's too early.

As I said it feels a bit more like a stepping stone, but an interesting one.

 

[jake jot]

From the presentation I linked to, he said that so far the "intrinsic" momentum space he's been using is flat. Hence currently no GR-like results have emerged. His goal is to use a curved momentum space instead, and with that hopes to get GR out, but so far it's too early.

As I said it feels a bit more like a stepping stone, but an interesting one.

Oh. I initially read about Smolin momentum space in a 2011 article.

Beyond space-time: Welcome to phase space | New Scientist

In Smolin 2011 ideas. The intrinsic is phase space. So he now says momentum space itself is intrinsic?

After it. I read theoretical models about spacetime and momentum space being both intrinsic. Not just a wave function in momentum space being the Fourier transform of a wave function in position space.

Meaning there is barrier between spacetime and actual momentum space (where exists monopoles). In Smolin present account. It seems spacetime is derived from momentum space?