Symmetry the new Ptolemaic Theory?

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  • #26
samalkhaiat
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Ernies said:
I deny that 99% of physicists really believe thst the goal of physics is a theory of everything -- at least if that means nore than the unification of gravity theory with the rest. The reason is very simple -- Godel's Theorem-- which certainly applies
I believe, physics is a logical system, illdefined by our experience. Or,
physics = math + observation,
so to speak.
Manny of us know how Godel's theorem works in mathematics. However, to prove the theorem in physics, one needs to know how to apply it (godel's theorem) to the set of all observations in physics!
Well, I do not know how to do this.
Since you are certain that godel's theorem applies in physics, therefore I should ask you to show us how?
I am certain you will be more famous than Godel himself, if you prove his theory in physics.
since no-one can handle in detail a non-denumerable infinty of axioms.
What is this. Who told you that TOE needs infinite number of axioms?

Only fanatics
What are these people?
religious and otherwise, think that a human mind can arrive at the explanation of everything
I thought these religious people believe that God and only God knows everything.
TOE will not put an end to physics.
My personal view is this: if mankind is not going to destroy the intelligent life on this planet, future physicists will arrive at equation which will have particular solutions such as John, Sofia and their pets.

lifting ourselves by our own bootstraps ____ I hope you don't believe you can.
No, I can not. Because the laws of nature (future TOE included) say this is not allowed.
And stop telling CarlB he is stupid: he isn't.
Wait a second. I never said or intended to say "he is stupid". How can I. I do not know the man.
From Carl's inaccurate statements about "physics", I infered:
1) he has a confused knowledge about physics,
2) he is not a physicist.
Niether 1) nor 2) means "he is stupid".
Sir, I am here to talk physics. Insulting people is not my intention.
So, do not accuse me of such thing, ok?

Like at least a couple of dozen
world-ranking scientists that I know of he just doesn't agree with you
Carl says: QED violates Lorentz invariance.
I say: this is nonsense.
So, out of your 24 world-ranking scientists, I want you to name only one who agrees/disagrees with Carl/me. Come back to me with a name.



sam
 
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  • #27
samalkhaiat
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CarlB said:
It's interesting that Bohm would reject a theory based on it being a violation of Lorentz symmetry. Here's what he says about the subject in his classic introduction to what is called Bohmian mechanics:
The Undivided Universe
D. Bohm & B. J. Hiley, Routlege, 1993
I was taught QM at Birkbeck by Basil Hiley who later became my research supervisor.So, I can say that I "read" this book 2 years before its publication in 1993!
Because of this close connection, I do not feel comfortable talking about the interpretation part of Bohm's work.
But, I can say this:
Mathematically, the "Bohmian Mechanics" is equivalent "only" to the x-space representation of Schrodinger equation (differential equation). If you write Schrodinger equation in the momentum space (integral eqution), you would see the troubles in deriving Bohm's equations.
In short, the freedom of representation of QM does not exist in Bohm's work.
When I read Bohm's paper[Phys.Rev.85(1952)],I raised the question of representation freedom to Hiley who said that Bohm was aware of this drawback from the begining.It is said, This problem was mentioned in the private communications between Einstein and Bohm in 1951.
This problem as well as the non-local nature of the "quantum potential", makes Bohm's approach unconvincing and troublesome when applied to local field theories.
I believe, professor Basil Hiley and his army of research students are still working on these problems.:confused:


sam
 
  • #28
CarlB
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samalkhaiat said:
Carl, you entered this thead by saying that symmetries are no longer important in physics.
Actually, I said no such thing. What I said, or at least intended to say, was that symmetries can be misleading when one is looking for an underlying theory. In crystallography, for example, the symmetries of the molecules that make up a crystal have little to do with the symmetry of the crystal itself.


As for the quote from Feynman, I told you that he was explaining to the "layman", the perturbative expansion of the 2-point Green's function and how higher order terms (graphs) would modify the form of propagator in QED processes:
G-->G(a,d)+G(a,b)V(b)G(b,d)+G(a,b)V(b)G(b,c)V(c)G(c,d)+...
Or,
x---x --> x---x + x---x---x + x---x---x---x + ...
There is no "derivation of massive propagator from massless one" in here.
What Feynman wrote about it, literally, was "The formula for E(A to B) is complicated, but there is an interesting way to explain what it amounts to." Feynman's comment was that it was (a) "interesting" and that this method (b) "explains" what the massive propagator "amounts to".

Spin it whatever way you want, he wasn't talking about just another detail in calculation. If that were the thrust of his comments, he'd have said something like "The formula for E(A to B) is complicated, but there is an interesting way that we can compute it." He didn't. Instead, he talked about "explaining" the propagator. His comment spoke to the ontology of the massive propagator, not to a calculational method.

And certainly, there is no violation of Lorentz invariance. Indeed, every term in the expansion respects lorentz invariance.
Yes, the problem arises with gauge invariance not Lorentz invariance (i.e. when you do the same thing to give mass to the L and R electron fields). You end up with a violation of Lorentz invariance when you try to implement a relativistic Bohmian mechanics through the series.

Carl, we know of no QED-process that violates the principles of relativity (Lorentz invariance).
This is only true in certain models, in particular the standard model. There are hundreds of articles on Arxiv proposing ways that Lorentz invariance may get violated. Physicists are exploring these things for reasons that are well explained in the cover article of the latest issue of Scientific American. It's not like I'm the only person out there suggesting that Lorentz invariance may have to go.

Carl
 
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  • #29
CarlB
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samalkhaiat said:
Because of this close connection, I do not feel comfortable talking about the interpretation part of Bohm's work.
This is too bad. I would think that your vantage point would give you a better view than most.

Mathematically, the "Bohmian Mechanics" is equivalent "only" to the x-space representation of Schrodinger equation (differential equation). If you write Schrodinger equation in the momentum space (integral eqution), you would see the troubles in deriving Bohm's equations.
In short, the freedom of representation of QM does not exist in Bohm's work.
This is a very beautiful statement and I agree with it completely. Where we disagree, and where I believe that I would follow Bohm and you would not, is that I believe that only the position representation is ontological. I believe that the momentum representation is just a mathematical convenience. My feelings about Lorentz invariance is the same. That is, that it is more or less an "accidental" symmetry of spacetime and so it is convenient to use Lorentz invariance to define theories that are automatically compatible with it.

This problem as well as the non-local nature of the "quantum potential", makes Bohm's approach unconvincing and troublesome when applied to local field theories.
Yes, this is why I reject Bohm's approach, at least as written. But if you expand the definition of time you can arrange for Bohm's version of QM to be local. I came up with the idea on my own but I believe that it's fairly obvious and is already in the literature. One must add an extra time parameter, call it "absolute time" that defines the time of the observer. With that addition, the wave part of Bohm's construction is used by the observer when the event is still in the future. As absolute time for the observer advances, the experiment moves from the observer's future into his past and the wave collapses to the particle track.

Let me look around and see if Hiley and students did or is doing this, or if it is an unconnected ontological theory of QM. It turns out to be hard to search Arxiv for, when I have some time later.

Carl
 
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samalkhaiat said:
Ernies said:
Many of us know how Godel's theorem works in mathematics. However, to prove the theorem in physics, one needs to know how to apply it (godel's theorem) to the set of all observations in physics!
Well, I do not know how to do this.
Since you are certain that godel's theorem applies in physics, therefore I should ask you to show us how?sam[\Quote]

Godel's theorem applies to any system of axioms--finite or denumerably infinite (I am not certain of higher orders of infinity)-- which is large enough to include ordinary arithmetic. Are you saying that physical theories are not essentially mathematical, or that they do not include ordinary arithmetic. Th e infinity was merely put in to exclude the idea that if only we put in a few more axioms it would all work out OK.

[Qote] So, out of your 24 world-ranking scientists, I want you to name only one who agrees/disagrees with Carl/me. Come back to me with a name.[/B]

sam
Bell (of Bell's Inequality) for starters, and Feynmann who certainly expressed equivalent views to me at the Geneva Nuclear Physics Conference of 1958, and is reported to have said in his final illness " There are things we just can't know". And he meant "can't" and not simply "don't"!! The others I would have to look up to be entirely accurate.
ernie
 
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samalkhaiat
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Ernies said:
samalkhaiat said:
Bell (of Bell's Inequality) for starters, and Feynmann who certainly expressed equivalent views to me at the Geneva Nuclear Physics Conference of 1958
I want the name of paper and/or book where Feynman and Bell (allegedly) said that quantum electrodynamics violates Lorentz invariance.I think your Feynman and Bell are not the Feynman and Bell that we (physicists) know very well:confused: :confused:

and is reported to have said in his final illness " There are things we just can't know". And he meant "can't" and not simply "don't"!!
Yeh, So? He certainly did not mean Lorentz invariant QED.
Feynman best contribution to physics was about Lorentz invariant QED.


sam
 
  • #32
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samalkhaiat said:
No, we do not make symmetries, we discover them. The real symmetries of the world are objective (not subjective) features.
Logic is an arbitrary set of rules, you could make your owns.
It is, isn't it.:wink:
Cheers
sam
Hi,

We discover symmetries true, but that does NOT imply that these symmetries are something FUNDAMENTAL rather than an EMERGENT property (and it is silly to claim that such thing would be an objective feature). It is true that in the business of particle physics (and therefore also string theory and to a lesser degree LQG) researchers do believe that going over to higher symmetry groups is ``the way´´ to unification (which leads to speculations about infinite dimensional (Lorentzian) Kac Moody algebra's :smile: ). However, there exist good arguments against such methodology and recently, very distinguished thinkers (such as 't Hooft) have expressed similar views about the ``thermodynamics´´ behind symmetry (such as the preference for flat coordinate systems in nature).

It is however entirely false to state that 99 percent of physicists think that unification is the ultimate goal of physics. Most of them actually don't care at all about the unification of GR with QM and are pleased to be able to calculate predictions of lab scale experiments (and many of them think it is an impossible problem anyway). Others actually regard it as science fiction or mathematics ...

Cheers,

Careful
 
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  • #33
samalkhaiat
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Careful said:
Hi,
We discover symmetries true, but that does NOT imply that these symmetries are something FUNDAMENTAL rather than an EMERGENT property
What is it that makes you so sure?
The argument was about "invent" versus "discover".
"invent" corresponds to subjective "things". These subjective "things" exist because we exist.
"discover" corresponds to "things" having real existence outside our mind. "Things" that are not influenced by us. These "things" exist even if we don't (this is the why "we discover them").This is the definition of objective "things".

(and it is silly to claim that such thing would be an objective feature).
Why not say;"it is silly to claim that such thing would be an EMERGENT property"?
What is this "EMERGENT property" anyway?
Does it exist out there and not influenced bu us? If yes (it must, because we discover symmetry), then it is an objective feature. Therefore, according to you, it is silly to claim that such thing would be an "EMERGENT property".:wink:


It is however entirely false to state that 99 percent of physicists think that unification is the ultimate goal of physics.
I used the verb "believe".
Just look in Phys.Rev.D(1930-2006) and count the number of papers which deal with particle physics, QG, SUSY, strings and other unification subjects, and then do the percentage!:surprised

Most of them actually don't care at all about the unification
I don't know about this. I didn't ask "Most of them", did you?:tongue2:


Cheers, and happy new year

sam
 
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  • #34
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**
What is it that makes you so sure?
The argument was about "invent" versus "discover".
"invent" corresponds to subjective "things". These subjective "things" exist because we exist. **

Nope, to discover - in the sense of making a lab experiment - is objective as far as the setup and the experimental outcome itself is concerned (and there it usually stops, subjectivity creaps in as soon as the statistics is done :smile: ). A property can be objectively true (in an appropriate statistical sense) but the *theory* dealing with this property can only be objectively *adequate* with respect to a universal Occam's razor. Now, this adequacy heavily depends upon our contemporary knowledge and can either (a) be falsified by a future experiment (at higher energies) (b) the theory is replaced by one which fits better Occam's razor or (c) the strategy underlying the theory is not suitable for one's goals (unification) and one has to look for a new theory which is at least as good.

**Why not say;"it is silly to claim that such thing would be an EMERGENT property"?
What is this "EMERGENT property" anyway? **

If you do not know what emergent is, then your statement is supersilly :smile:. Let me give a simple example : the correlations in the data discovered in the 19'th century concerning experiments on electricity lead Maxwell (and others) to the *invention* of electromagnetism. It was Lorentz I presume who saw that Maxwell's laws were invariant under the group of hyperbolic transformations and consequently (due to the importance of special relativity) the modern Lorentz covariant formulation was invented (in terms of vector potentials, field strenghts and Hodge duals). This formulation clearly posses a symmetry (which was of course known before, but I just like telling the story :smile: ) which is extremely important in the endeavour of finding solutions. So, SYMMETRY became (and was this in a less formal way already for a long time) itself an important principle (also due to Noether's theorem) - which explains the exploration of higher local symmetry groups. Therefore, the only fair statement we can make is that observations (more or less objective truths) are consistent with effective theories (effective in the sense that all *fundamental* particles are assumed to be pointlike) which have local gauge symmetries. Now, these ``fundamental´´ particles are not fundamental at all of course : at sufficiently high energies we will discover new substructures and the ``points´´ shall become bound states of interacting points and hence get an effective spatial dimension (such as with the proton and the quarks). So, such strategy can never lead to a theory of ``everything´´ since you can not even make a falsifiable prediction of what the next generation of subunits will be at sufficiently high energies. Moreover, higher and higher gauge groups lead to more and more ``fundamental´´ interactions and is therefore an extremely uneconomic picture of nature (and not particularly insightful I must add). Therefore one might contemplate that these theories are just effective as is their symmetry : it could very well be that -say- at the planck scale a (deterministic ?) fundamental dynamics is chaotic and posesses no symmetry at all (of course I do not think you have to go as far as the Planck scale for this :wink: ).


**
I used the verb "believe".
Just look in Phys.Rev.D(1930-2006) and count the number of papers which deal with particle physics, QG, SUSY, strings and other unification subjects, and then do the percentage!:surprised **

Doing the percentage is stupid ! :grumpy: Percentages say something about money, not about intelligence.

** I don't know about this. I didn't ask "Most of them", did you?:tongue2: **

Most people I asked think about it in this way :biggrin: And I guess many mentors on this forum (looking at their attitude) do too (I know for sure Vanesch does).

Cheers,

Careful
 
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samalkhaiat said:
Ernies said:
samalkhaiat said:
I want the name of paper and/or book where Feynman and Bell (allegedly) said that quantum electrodynamics violates Lorentz invariance.I think your Feynman and Bell are not the Feynman and Bell that we (physicists) know very well:confused: :confused:
Yeh, So? He certainly did not mean Lorentz invariant QED.
Feynman best contribution to physics was about Lorentz invariant QED.
sam
I am a retired theoretical physicist (aged 79) who actually knew and talked to both Bell and Feynmann. Unless your security clearance is very high you are unlikely to have seen my work, except for one on thermoelectricity published in Phys. Rev in 1968(+/- 1).Your comments seem to have no relevance to my remarks, and I decline to travel several dozen miles to the University and dig up papers for what will clearly serve no purpose. (And what makes you think publication is a guarantee of truth anyway?)

Try to open your mind.

Goodbye

Ernie
 
  • #36
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Ernies said:
samalkhaiat said:
Ernies said:
I am a retired theoretical physicist (aged 79) who actually knew and talked to both Bell and Feynmann. Unless your security clearance is very high you are unlikely to have seen my work, except for one on thermoelectricity published in Phys. Rev in 1968(+/- 1).Your comments seem to have no relevance to my remarks, and I decline to travel several dozen miles to the University and dig up papers for what will clearly serve no purpose. (And what makes you think publication is a guarantee of truth anyway?)
Try to open your mind.
Goodbye
Ernie
p.s. the above uncertainty could be +/-2. And so far as publication is concerned, I would remind Sam of Jonny van Neumann's so-called proof that "Action at a distance" theories were neccessarily self-contradictory.As Bell (yes the same Bell) commented this 'proof' was not only stupid but silly. Yet Neumann's 'Proof' held up advances for 50 odd years.
 

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