Special Relativity Between Reality and Illusion

[Manaf]

Hi,
Q1: Do the effects of time dilation and length contration really happen, or they seem to happen to us being in different inertial frame, because our means of observation ( say, by looking by means of coming relativistic beams of light) draw this illusion on us and show us something different from the reality.

Q2: Do the 2 effects kind of cancel each other (contraction/dilation) so as to make the light speed constant?

Q3: In Twin paradox, the difference in ageing should be just a relativistic concept (or at least, that's what I think). How could the physiological and chemical processes inside the bodies be affected. Is It possible that the chemical reaction used to proceed in 1 sec and now in 2 sec just because you travel so fast?!

thanks

 

[jtbell]

For my opinion on this, see posting #10 in the following thread:

https://www.physicsforums.com/showthread.php?t=128068

 

[DaveC426913]

Q1: A reality does not exist over and above what we measure. So yes, it really happens.

Q2: You've got the cart before the horse. Because space and time are limited by light speed, so it is that contraction and dilation are what happens.

(Think of a seesaw. Spacetime and lightspeed are the axle, the 2 seats are measurable effects. You're saying "the seats go up and down, thus ensuring any movement of axle cancels out and it remains motionless". I'm saying "no - the axle remains motionless, period. It is the seats that are free to move, subject to the axle's domination".)

Q3: "...a relativistic concept..." Relativity is the reality of our universe. What is illusory is our misguided perception that time runs at the same speed everywhere in it.


This is very important to accept or you will always struggle with these issues. Our universe is not built the way Netwon thought. Time is not constant and unchanging, mass is not constant and unchanging. These things are resultant properties of the controlling principle of the universe which is relativity.

 

[pervect]

Hi,
Q1: Do the effects of time dilation and length contration really happen, or they seem to happen to us being in different inertial frame, because our means of observation ( say, by looking by means of coming relativistic beams of light) draw this illusion on us and show us something different from the reality.

A question about reality is ultimately a philosophical question. What is "real" - and how do you know when something is "real"?

Because philosophical views vary so widely, we would need to know more about your personal philosphical views to give an intelligible answer.

I personally tend to regard things which are observer-independent as "real". This philosophical viewpoint works well in most disciplines (but perhaps not in quantum mechanics). From my philosophical viewpoint, time and distance are not "real", or perhaps not "as real" as the Lorentz interval, because time and distance depend on the observer, while the Lorentz interval is observer-independent.

This may or may not be useful to you, depending on your personal philosophy as to what constitutes "real".

 

[CarlB]

Hi,

There are several different points of view that these questions can be approached from. I will give here an approach that gives the same computations as the more common interpretation, but is less common. Essentially, it was this interpretation that was eliminated by Einstein's 1905 paper on special relativity. This is the "Lorentz-Poincare ether theory". You can learn more about it by searching on the web. For example:
http://www.google.com/search?hl=en&lr=&q=lorentz+poincare+ether+site:arxiv.org

A1: Reality does exist over and above what we measure, so no the effect does not "really" happen, at least in my opinion. You can choose either way of thinking about it, in that you will get the same result no matter which way you think about it. It's just a matter of interpretation. However, do note that if you get asked questions on an exam, your professor may insist that you accept one particular interpretation over another. In this case, simply parrot back what you've been told.

A2: Yes, the speed of light is in units of length over time, so length and time both have to be affected together if the speed of light is to be unchanged by change of inertial reference frame.

A3: Yes, if you wish you can think of the aging of a twin as being slowed down because the chemical reaction rates are slowed down. All these effects boil down to the same thing, that electricity and magnetism (and other forces) are effected by changes in reference frame. Since chemical processes are made out of electricity and magnetism, they too are slowed down.

Maybe a parable would help here. When God designed the universe, he wanted complicated creatures to be able to exist on it. Complicated creatures need complicated chemistry and chemistry depends (almost) exactly on the laws of physics. In order to allow His creatures to thrive, He therefore designed the universe so that the laws of physics would be nearly identical for every inertial frame. That way, if a planet moved from one part of the galaxy to another, it wouldn't have all its creature's DNA suddenly quit working, for example.

As a result of His design, it is very difficult for physicists to discern the difference between one inertial frame and another. This fact gives a tool for determining what physical laws matter must follow. The rule is that the results of your calculation cannot depend (much) on the choice you make for the frame of reference.

Regarding the "almost" and "much" included in parentheses in the above. Compared to God (and mathematics), humans are very ineffective things. Humans are very weak and short lived. The equipment that they build is very clumsy and produces very inaccurate measurements. If humans were strong they would be able to accelerate electrons to the Plank mass with their bare hands. If humans were long lived they would be as old as the stars. If our equipment were not clumsy it could probe space down 10^500 factors below the size of quarks. If our measurements were accurate, we would know the mass of the electron to a trillion decimal places instead of twelve.

Because of the ineffectiveness of humans, it is not possible for us to (yet) discern the difference between two inertial rest frames. Now there is a true reference frame and if we knew what it was, we could figure out how fast the twins were really aging, and we would know which was getting older faster. But God created the universe so that our chemistry would not depend on the inertial frame and in doing this, as an accidental side effect, He made it very nearly impossible for us to distinguish between inertial frames.

Therefore, so long as the twins never meet again, we cannot tell which one is really aging faster. God knows, but we do not. Maybe someday we will figure out how to find the true reference frame, the one that gives real times. However, if the twins do eventually meet up again, then we can cancel out the effects of our not knowing what the true reference frame is, and then we can deduce which twin has aged more.

Carl

 

[Manaf]

Hi,
thanks to all of you.
Wow..I didn't know my question is a topic of such controvestial arguments..I felt a bit that my question is somewhat philosophical.

What I meant by "real" is that it is a physical phenomenon that is , as pervect said, observer-independent.
I thought maybe these effects should not happen but because of our ineffective means of observation, they appear to be like so, which is against DaveC426913 veiw:)
Like because the light (means of perception) travels from different positions or emitted at different times ,or because our motion makes us moving closer to a source of light farther than the other while they were simulatanious.

 

[russ_watters]

Just for a little simple (too simple, but it is something that may not have been clear from the more in depth posts above), we do observe relativistic effects to occur. While determining exactly what happened depends on the observer, both observers will agree that relativity is the cause of any disagreement.

To give an example, GPS satellites have their clock rates adjusted prior to launch so that they will stay in sync with earthbound clocks once launched in orbit.

Regarding Q3, the twins paradox is a thought experiment and AFAIK, we have not yet been able to witness relativistic phenomena in biologic processes. But time dilation has shown up in enough differing physical processes that it is reasonable to conclude that it is not just individual physical processes that happen to be affected by speed in exactly the same way, but it is time itself that is observer dependent.

 

[George Jones]

I agree with pervect about philosophy and personal philosophy.

Personally, I (like, I think, Russ) vote real.

After all, the universe isn't Strawberry Fields!

 

[neophysique]

Hi,
Q1: Do the effects of time dilation and length contration really happen, or they seem to happen to us being in different inertial frame, because our means of observation ( say, by looking by means of coming relativistic beams of light) draw this illusion on us and show us something different from the reality.

Q2: Do the 2 effects kind of cancel each other (contraction/dilation) so as to make the light speed constant?

Q3: In Twin paradox, the difference in ageing should be just a relativistic concept (or at least, that's what I think). How could the physiological and chemical processes inside the bodies be affected. Is It possible that the chemical reaction used to proceed in 1 sec and now in 2 sec just because you travel so fast?!

thanks

A1: The data on the ISS satellite shows a slower clock while
the GPS satellite shows a faster clock (compared with a ground
clock). Since elevation makes all clocks faster (gravitational
red shift), the slower clock can be argued to be real velocity time dilation,
if mechanical effects are all accounted for.

A2: This is the problem with Special Relativity. If length is contracted
and time is dilated as well, neither length contraction nor time dilation
are real but mere math manipulations.

A3: It's possible that one moves through time at different "rates"
according to their initial accelartions.

 

[yogi]

Pervect gave the enlightening answer to all the questions - it is the Lorentz interval that is real - it is the same for all observers. Space measurments and time measurments individually are observer dependent - and therefore one needs a precise definition of what "real" means

Example - in a GPS satellite - the satellite clock appears to run slower than the Earth based clock (if we ignor altitude) - but the satellite clock has both a temporal component and a spatial component when measured from the Earth clock - so the satellite clock accumulates less time during a one orbit journey - but according to SR it cannot be said that it runs slower - it just accumulates less time during the spacetime interval. In contrast, in Lorentz ether theory, the satellite clock is claimed to actually run slower.

 

[MeJennifer]

Example - in a GPS satellite - the satellite clock appears to run slower than the Earth based clock (if we ignor altitude) - but the satellite clock has both a temporal component and a spatial component when measured from the Earth clock - so the satellite clock accumulates less time during a one orbit journey - but according to SR it cannot be said that it runs slower - it just accumulates less time during the spacetime interval. In contrast, in Lorentz ether theory, the satellite clock is claimed to actually run slower.

Quite correct, that is the difference between the two theories!

While the theory of special relativity postulates a length contraction as a contraction of space and a time dilation as a contraction of time the Lorentz ether theory maintains the notion of absolute time and space and postulates that clock rates slow down due to mass increase and lengths get contracted due to traveling in the ether.

So far both theories show the same results.
Personally the Lorentz ether theory makes makes a lot more sense.

 

[clj4]

Quite correct, that is the difference between the two theories!

While the theory of special relativity postulates a length contraction as a contraction of space and a time dilation as a contraction of time the Lorentz ether theory maintains the notion of absolute time and space and postulates that clock rates slow down due to mass increase and lengths get contracted due to traveling in the ether.

So far both theories show the same results.
Personally the Lorentz ether theory makes makes a lot more sense.

Aren't you forgetting that Lorentz theory needed (and still needs) to have additional ad-hoc assumptions tailored specifically for each experiment? I.e. the LET principles are not sufficienr, one needs those ad-hoc additions in order to justify the results of the many experiments that are explianable by SR from first principles, no ad-hoc additions.
So, SR and LET are NOT equivalent.

 

[CarlB]

Aren't you forgetting that Lorentz theory needed (and still needs) to have additional ad-hoc assumptions tailored specifically for each experiment? I.e. the LET principles are not sufficient, one needs those ad-hoc additions in order to justify the results of the many experiments that are explianable by SR from first principles, no ad-hoc additions. So, SR and LET are NOT equivalent.

I've never heard of any such assumptions. To get the Lorentz theory from Einstein's special relativity, all one need do is assume that one of the inertial frames is the ether.

The physical issues are well described in Physics Letters A 333 (2004) 355:
http://www.citebase.org/abstract?id=oai%3AarXiv.org%3Aphysics%2F0410245 or
http://arxiv.org/abs/physics/0410245

Carl

 

[clj4]

I've never heard of any such assumptions. To get the Lorentz theory from Einstein's special relativity, all one need do is assume that one of the inertial frames is the ether.

The physical issues are well described in Physics Letters A 333 (2004) 355:
http://www.citebase.org/abstract?id=oai%3AarXiv.org%3Aphysics%2F0410245 or
http://arxiv.org/abs/physics/0410245

Carl

The Consoli paper is well known as an example of what happens when someone writes papers about hypothetical experiments in ignorance of previously executed experiments. Consoli/Constanzo seem ignorant of the fact that the MMX experiment in refractive media had already been run. Twice: once by Shamir and the second time by Trimmer, both times with null results. See references here:

Trimmer et al., Phys. Rev. D8, p3321 (1973); Phys. Rev. D9 p2489 (1974).
A triangle interferometer with one leg in glass. They set an upper limit on the anisotropy of 0.025 m/s. This is about one-millionth of the Earth's orbital velocity and about 1/10,000 of its rotational velocity.

Shamir and Fox, N. Cim. 62B no. 2 (1969), p258.
A repetition of the MMX with the optical paths in perspex (n = 1.49), and a laser-based optics sensitive to ~0.00003 fringe. They report a null result with an upper limit on Vaether of 6.64 km/s.

As to the support of my
post, it comes from a well known CMWill paper on the subject:

http://prola.aps.org/abstract/PRD/v45/i2/p403_1

It is not sufficient to assume the presence of the one priviledged frame, one must also assume that light speed is isotropic in tha frame (but not in the other frames). One must also ad ad-hoc assumptions for each particular experiment (see the CMWill paper) or see the well known Mansouri-Sexl papers from 1977.

 

[CarlB]

The Consoli paper is well known as an example of what happens when someone writes papers about hypothetical experiments in ignorance of previously executed experiments.

I don't mean to quote Consoli on the experiments, but instead simply to point out that Lorentzian relativity is equivalent to Einstein's special relativity. By "Lorentzian relativity" I do not mean to describe the 1904 theory of Lorentz (which if I recall, had moving objects contracted but did not deal with the rate of time experienced by moving objects and so was just wrong), but instead simply Einstein's relativity with the additional supernumerary postulate that one of the inertial reference frames is preferred (but undetectable). This, of course, is equivalent to Einstein's relativity.

The phrase from logic that comes to mind is "absence of evidence is not evidence of absence".

As to the support of my
post, it comes from a well known CMWill paper on the subject

I don't have access to that at home, maybe you can quote from it. The abstract certainly doesn't read on Lorentzian relativity. I'm going to guess that the author showed that some theory that is not equivalent to Einstein's relativity was eliminated by experimental data.

Carl

 

[clj4]

I don't mean to quote Consoli on the experiments, but instead simply to point out that Lorentzian relativity is equivalent to Einstein's special relativity. By "Lorentzian relativity" I do not mean to describe the 1904 theory of Lorentz (which if I recall, had moving objects contracted but did not deal with the rate of time experienced by moving objects and so was just wrong), but instead simply Einstein's relativity with the additional supernumerary postulate that one of the inertial reference frames is preferred (but undetectable). This, of course, is equivalent to Einstein's relativity.

"That" is the Mansouri-Sexl theory. And it requires additional ad-hoc hypothesises for each experiment. I have a scan of the Mansouri-Sexl papers, I'll try to append them on my next post.

I don't have access to that at home, maybe you can quote from it. The abstract certainly doesn't read on Lorentzian relativity. I'm going to guess that the author showed that some theory that is not equivalent to Einstein's relativity was eliminated by experimental data.

I have a scan of this paper someplace as well. CMWill is talking about the "official" LET, which is the Mansouri-Sexl test theory. He quotes exactly the ad-hoc "additions" for a series of experiments. That would complete the proof, correct?

 

[samalkhaiat]

Hi,
Q1: Do the effects of time dilation and length contration really happen, or they seem to happen to us being in different inertial frame, because our means of observation ( say, by looking by means of coming relativistic beams of light) draw this illusion on us and show us something different from the reality.

Experiments show that fast moving elementary particles live longer than their lifetimes. This is a real fact not illusion. It has been conclusively verified and confirmed by direct experiments, and it is now beyond any doubt.

Q2: Do the 2 effects kind of cancel each other (contraction/dilation) so as to make the light speed constant?

The constancy of the speed of light is one of the two postulates of SR. As such, it is logically impossible to determined the truth-value of any of the postulates. Using a result from the theory to examine the postulate leads only to a trivial information.

Q3: In Twin paradox, the difference in ageing should be just a relativistic concept (or at least, that's what I think). How could the physiological and chemical processes inside the bodies be affected. Is It possible that the chemical reaction used to proceed in 1 sec and now in 2 sec just because you travel so fast?!

Why not? Almost every thing indicates that physiological processes follow the laws of physics.
As for the twin, they are not "realy" a Twin because their reference frames are not equivalent. One of them uses non-inertial frame. A complete explanation of the paradox can only be given within the framework of general relativity.


regards

sam

 

[samalkhaiat]

Now there is a true reference frame and if we knew what it was, we could figure out how fast the twins were really aging, and we would know which was getting older faster.

Does God live in this reference frame?

But God created the universe so that our chemistry would not depend on the inertial frame and in doing this, as an accidental side effect

Accidental? Does this mean that God did not mean to do it?

He made it very nearly impossible for us to distinguish between inertial frames.

One would think that God makes things either possible or impossible, NOT "very nearly impossible"!


sam

 

[CarlB]

Accidental?

Accidental means that it is a low energy symmetry, one that disappears at higher energies. Since the standard model is only an effective theory, any of its symmetries could be accidental.

One would think that God makes things either possible or impossible, NOT "very nearly impossible"!

No, a lot of things are very very difficult. For example, if it were just a little bit easier to build nuclear weapons, a good bit of the world would have become radioactive wastelands back in the 1940s.

Getting back to physics, if the elementary particles are composites made up of preons, we really cannot be certain what the maximum speed of those preons are. It's easy to suppose that they are just like everything else we see and limited to speed c, but then again, we can't get at them so we can't measure their speeds. It's a region where we have no measurements.

Carl

 

[samalkhaiat]

Accidental means that it is a low energy symmetry, one that disappears at higher energies.

Yeh, this symmetry is the fairyland symmetry.
Look Carl, if you want to look for violation of some Lie symmetry, then you should look at low energy phenomena (at large length scale).

Since the standard model is only an effective theory, any of its symmetries could be accidental.

The correct statement is; the standard model could be an effective theory of more symmetric one. And this "deep" theory must show, in certain limit, all the symmetries of the SM.

No, a lot of things are very very difficult. For example, if it were just a little bit easier to build nuclear weapons, a good bit of the world would have become radioactive wastelands back in the 1940s.

We were talking about what God can or cann't make. What I wanted to tell you is this;
It is IMPOSSIBLE, even for God, to distinguish between inertial frames full stop.

Getting back to physics, if the elementary particles are composites made up of preons, we really cannot be certain what the maximum speed of those preons are. It's easy to suppose that they are just like everything else we see and limited to speed c, but then again, we can't get at them so we can't measure their speeds. It's a region where we have no measurements.

Physics! This is rubbish not physics.

1) Do we measure the speed of quarks?
No, we don't because we cann't.
2) At the quark-level,Do we know that c is still the c we know?
Yes we do.
3) How do we know that without any measurment?
Because, the physics at the quark-level (theory & experiments)
respects Lorentz symmetry.
Regarding the unsuccessful preon models, as far as I know almost all of them are Lorentz invariant, which means that the "speed" of massive(massless) preon is less than (equal to) c.


regards

sam

 

[CarlB]

The correct statement is; the standard model could be an effective theory of more symmetric one. And this "deep" theory must show, in certain limit, all the symmetries of the SM.

Are you willing to make this a general statement about all physical systems? That is, that the low energy phenomena of any possible physical system must always be less symmetric than higher energy phenomena of the same system? If you are, I'm willing to provide counterexamples (that quantum field theory applies to). If you are not, then please expand on why a deeper theory must be of the very limited sort that you describe rather than the more general sort that can be of the type I suggest.

Carl

 

[samalkhaiat]

Are you willing to make this a general statement about all physical systems? That is, that the low energy phenomena of any possible physical system must always be less symmetric than higher energy phenomena of the same system? If you are, I'm willing to provide counterexamples (that quantum field theory applies to). If you are not, then please expand on why a deeper theory must be of the very limited sort that you describe rather than the more general sort that can be of the type I suggest.

READ my statement carefully. This is what I said;

The SM COULD (not must) be an effective theory of more symmetric one. And this deep theory (if any) MUST show, in certain limit, all symmetries of the SM (correspondence principle).

Is this a general statement? No, it is not. And nobody knows whether it is true in general. Nevertheless, we do make such a statements for the following reasons;
1) we want to do physics.
2) the whole history of (symmetries in) physics has been the gradual realization that Lie symmetries do not appear and/or disappear in an arbitrary or (accidental) manner. On the contrary, our experiences show that deeper theories have a larger Lie symmetry. So, nuless experiment shows otherwise, is is only natural to suppose that this order should apply to the SM.
3)we have no reason to abandon the correspondence principle which asserts that "the expression of a new theory must approach the mathematical formalisim of the theory that it attempts to supersede".
4) the success of the electroweak theory;
At high energy the symmetry is SU(2)XU(1).
At low energy it is only a U(1).

regards

sam

 

[CarlB]

2) the whole history of (symmetries in) physics has been the gradual realization that Lie symmetries do not appear and/or disappear in an arbitrary or (accidental) manner.

Are you willing to make this statement about all known physical systems? That is, that the Lie symmetries of the low energy physics of a system are never more symmetric than the Lie symmetries of the high energy physics of the system? If you are, I'm willing to prove you wrong with physical examples. If you are not willing, then you must admit that there are physical examples of effective theories that are more symmetric than the deeper theories that lie beneath them, and that these provide counterexamples to your logic.

So, nuless experiment shows otherwise, is is only natural to suppose that this order should apply to the SM.

In the early 20th century there was no reason to suppose that mass and energy were not individually conserved. Do you admit that it would have been very natural to apply your word "rubbish" to Einstein's work that suggested that energy and matter could be converted into each other?

3)we have no reason to abandon the correspondence principle which asserts that "the expression of a new theory must approach the mathematical formalisim of the theory that it attempts to supersede".

I agree with this completely and have never ever suggested anything to the contrary. In the many physical systems where the low energy (effective) physics has more symmetry than the high energy physics, the correspondence principle applies. What bothers me about many recent attempts at unification is that the correspondence to the standard model is expected to show up only at some very distant time in the future (i.e. after everyone involved with the theory has already gotten tenure). [Not even wrong.]

4) the success of the electroweak theory; At high energy the symmetry is SU(2)XU(1). At low energy it is only a U(1).

I agree that this could be a clue. But on the other hand, many thousands of very intelligent physicists have spent large amounts of time trying to use this clue to further unify the forces for several decades and have failed. This is also a clue.


Many physicists have expressed disatisfaction with the standard model particularly with its large numbers of arbitrary parameters. Interpretations of quantum mechanics are so numerous that it is easier to find two physicists with the same birthday than two who agree on what quantum mechanics means. That is reminiscent of the situation when Einstein broke off into new ground. Under these sorts of conditions, ALL of the assumptions of physics should be examined anew.

But we've gotten far afield of the original question, which was about the possibility of a preferred reference frames in relativity. Let me write another post and get us back on topic.

Carl

 

[CarlB]

It is IMPOSSIBLE, even for God, to distinguish between inertial frames full stop.

David Bohm, of Bohmian mechanics fame, believed otherwise. See "The Undivided Universe". Chapter 12 has to do with relativity. Of particular interest is section 12.8, "On the meaning of non-Lorentz invariance of processes involving individual beables". The index lists page 292 for "preferred frame" and page 290 for "Lorentz ether" which reads on my comments on the Lorentz Ether Theory directly. Also see page 346 which shows up in the index. As I recall, this is where he discusses the possibility of future experiments showing violations of Lorentz symmetry.

Physics! This is rubbish not physics.

Bohm has an important physical effect named after him, the Aharonov-Bohm effect. I don't see how you have the standing to call his ideas rubbish. There are still a lot of physicists working on his ideas.

1) Do we measure the speed of quarks? No, we don't because we cann't.

I've never suggested otherwise

2) At the quark-level,Do we know that c is still the c we know? Yes we do.

I agree completely. This was never an object of disagreement.

3) How do we know that without any measurment? Because, the physics at the quark-level (theory & experiments) respects Lorentz symmetry.

Agreed. You've made a series of clearly true statements but I'm not sure what your point is. I'm going to guess that your logic is to point out that quarks are subparticles of protons and neutrons and yet quarks obey Lorentz symmetry just like neutrons and protons do. Therefore, perhaps by a sort of induction, all deeper subparticles must also obey Lorentz symmetry.

Let's apply your logic to the neutrons and protons themselves. Back before quarks were accepted would you have argued that all known particles carry integral electric charges and therefore quarks must too? Would you have argued that all known particles can be found in a free state and therefore quarks must too?

Regarding the unsuccessful preon models, as far as I know almost all of them are Lorentz invariant, which means that the "speed" of massive(massless) preon is less than (equal to) c.

Agreed. But what is your point? Is it that since "almost all" preon models are Lorentz invariant then any accurate preon model must also be Lorentz invariant? Do you have an outline of a proof that it is impossible for a non Lorentz invariant preon model to produce Lorentz invariant bound states? Or are you saying it's impossible only because you've never heard of it?

If you had been around in 1905 would you have rattled on about how "almost all" spacetime models include a universal time? Would you have gone on about how "almost all" models of elementary particles are symmetric under parity? Before quantum mechanics would you have used the logic that "almost all" models of elementary particles allow simultaneous knowledge of position and momentum? My experience with democracies and truth have not convinced me that the majorities are always right. Especially when physics requires revolutions.

Carl

 

[samalkhaiat]

Are you willing to make this statement about all known physical systems? That is, that the Lie symmetries of the low energy physics of a system are never more symmetric than the Lie symmetries of the high energy physics of the system? If you are, I'm willing to prove you wrong with physical examples. If you are not willing, then you must admit that there are physical examples of effective theories that are more symmetric than the deeper theories that lie beneath them, and that these provide counterexamples to your logic.

I stand ready to be converted in a moment by convincing argument. The question is; Are you able to provide such an argument? I am very much in doubt!

Generalization of my statement is (as I said before) meaningless, because it is a common BELIEF among physicists. The SM, string theory and supergravity represent a solid ground for this belief.
We know of no fundamental principle as to why nature seems to reveal a larger Lie symmetry at small distances.
Having said this, I do, however, want you to tell me where, in physics, do I find a Lie symmetry that gets larger in the low energy limit?

In the early 20th century there was no reason to suppose that mass and energy were not individually conserved. Do you admit that it would have been very natural to apply your word "rubbish" to Einstein's work that suggested that energy and matter could be converted into each other?

NO, because this was a result from a mathematically sound theory with countless experimental verifications.
By "mathematically sound" I mean logical consistency and ability to explain a number of known facts.

I agree that this could be a clue. But on the other hand, many thousands of very intelligent physicists have spent large amounts of time trying to use this clue to further unify the forces for several decades and have failed. This is also a clue.

Like most physicists, I think science is going in the right direction.

ALL of the assumptions of physics should be examined anew.

If you think that physics needs to be rewritten, then DO IT and show us a solid results. Don't just sit there and through garbage on us.

regards

sam

I would like to apologize for the delayed-reply. I promised my two daughters not to do any work during our holiday.

 

[CarlB]

Generalization of my statement is (as I said before) meaningless, because it is a common BELIEF among physicists. The SM, string theory and supergravity represent a solid ground for this belief.

You're saying that the justification for physicists believing what they believe is that they believe it. If we were talking about religion or politics, you'd be calling this circular reasoning.

The best argument for special relativity is that it has gotten us this far, why should we consider abandoning it now. But the same argument applies against every revolution that has ever been done in physics. Lee Smolin's new book goes to great length describing how difficult every one of the previous revolutions.

Having said this, I do, however, want you to tell me where, in physics, do I find a Lie symmetry that gets larger in the low energy limit?

The first and most obvious example is the optics of crystals. The presence of birefringence (and "trirefringence") give optical evidence of anisotropy in the crystal and is a hint of the structure of the crystal.

A crystal in the cubic system exhibits no birefringence and so appears to possesses SO(3) symmetry to photons (of low enough energy). But at x-ray energies, the symmetry is broken (to a discrete symmetry).

Lee Smolin's latest book describes the ether theory of the late 19th century as a "matter" theory because it tried to explain everything in the world as matter. The ether was invisible matter that carried the vibrations of light. Since light travels at a very high speed, it was thought that the ether must be very stiff. Light moving in a crystal follows the analogy perfectly.

For the case of the substance which moves when light travels, the analogy to the crystal is that as long as our energies are low, the Poincare symmetry will appear to be a continuous one. But at high enough energies, it is also possible that the symmetry will be broken to a discrete symmetry. In this case, the breaking would be by the appearance of a preferred reference frame and the reduction of Poincare symmetry to the symmetries that existed before the invention of SR.

NO, because this was a result from a mathematically sound theory with countless experimental verifications. By "mathematically sound" I mean logical consistency and ability to explain a number of known facts.

Classical mechanics was a mathematically sound theory with countless experimental verifications. It had logical consistency and was able to explain a number of known facts. So why search for a new theory outside its bounds?

Like most physicists, I think science is going in the right direction.

I've been enjoying Lee Smolin's new book "The Trouble With Physics". He makes it very clear that at any given time, very few physicists are worried about the direction of the field. Instead, they just calculate. But Smolin also points out the difficulties that attend the present situation and he makes a pretty good argument that something radical needs to be done.

If you think that physics needs to be rewritten, then DO IT and show us a solid results. Don't just sit there and [throw] garbage on us.

I have great respect for your knowledge of physics and appreciate your spending time here defending what is commonly believed to be true. Earlier, I gave an alternative interpretation of relativity, that it is a consequence of an anthropic principle and you didn't respond to it. As far as showing you a solid result, as long as you refuse to imagine that anything other than what you've been taught is true, it would be a waste of time. Besides, it doesn't belong on this forum.

Do you agree that if the naive ether theory of the late 19th century (i.e. Gallilean invariance, the straw man that SR defeated) were true, then the biochemistry of living organisms would depend on their orientation? Do you agree that if gravitation and acceleration were not equivalent then biochemistry would depend on the gravitational potential that a planet experiences? Do you agree that both of these effects would tend to make it more difficult for life to survive? Do you agree that one can make a first principles argument for SR and GR on the basis of the anthropic principle? Do you agree that if our foundation for believing SR and GR is the anthropic principle, then it is reasonable to explore physics ideas that treat SR and GR as only very good approximations? What I'm curious here is exactly which step in the above reasoning you find fault with.

Carl

 

[samalkhaiat]

David Bohm, of Bohmian mechanics fame, believed otherwise.

I know Bohm well enough to tell you that he never believed in "accidental relativity". He BELIEVED in (what he called) a "field" theory of "unbroken whole" which (when formulated) contains relativity and quantum theory. His notion of "implicate order" does not mesh well with any "accidental" symmetry.

"On the meaning of non-Lorentz invariance of processes involving individual beables". The index lists page 292 for "preferred frame" and page 290 for "Lorentz ether" which reads on my comments on the Lorentz Ether Theory directly.

Bohm spent the last 30 years of his life (at Birkbeck college) trying to formulate his "field" theory. He experimented with many, but never found the appropriate mathematical system for his (philosophical) concepts.
This is the reason for the "speculative" material of the last 4 chapters of his book with Hiley.
What Bohm & Hiley said in chapter 12, regarding QM versus relativity,is the following:
IF QM does not break down at some fundamental level, and IF a metric tensor field CAN BE defined on such level, then a LARGE quantum fluctuations could prevent this metric from having diagonal form, i.e. spacetime may cease to be Minkowskian and Lorentz group ceases to be fundamental.
Now, it is equally possible that it is the QM that breaks down at such level. In this case, Lorentz symmetry may continue to be fundamental.
I believe, the book discusses this possibility in chapter 14.

Also see page 346 which shows up in the index. As I recall, this is where he discusses the possibility of future experiments showing violations of Lorentz symmetry.

Not just in the book, but even in private coversations, Bohm & Hiley never explained or proposed such a "future" experiment.
In chapter 14 ,I think, they claim that their "field theory" (when formulated properly) COULD go beyond both relativity and QM. I know their method of introducing "arbitrary forces & momenta" into Bohm's equation of motion of QM. I also know that the method does not work.

Bohm has an important physical effect named after him, the Aharonov-Bohm effect. I don't see how you have the standing to call his ideas rubbish. There are still a lot of physicists working on his ideas.

Nice one.
I heppened to be the last person, to whom, Bohm spoke physics just one hour befor his death on Oct.27th.1992.

You never presented a view similar to that of Bohm or/and (my ex supervisor) Hiley. I suggest you read AND understand the book you mentioned.

As for the A-B effect, let me tell you that it is a Birkbeck College effect, this is because; 1) Bohm worked (even after retirement) at Birkbeck for 31 years, and most importantly; 2) the effect was first discovered at Birkbeck in 1949 by R. Siday (who died from alcohol abuse). For 10 years, the poor man work went unnoticed until Bohm and his student Aharonov "REDISCOVERED" the effect in 1959 at Bristol university.
After Bohm's death, Hiley promised to speak out and make this fact known to people. Apart from one paragraph in one of his articles in the royal socity, Hiley seems to have forgotten the promise he made in his professorship lecture in 1996.

SO PEOPEL, THE A-B EFFECT SHOULD BE CALLED THE SIDAY'S EFFECT.

Agreed. You've made a series of clearly true statements but I'm not sure what your point is. I'm going to guess that your logic is to point out that quarks are subparticles of protons and neutrons and yet quarks obey Lorentz symmetry just like neutrons and protons do. Therefore, perhaps by a sort of induction, all deeper subparticles must also obey Lorentz symmetry.

The point is this; We have NO good reasons (experiment or good theory) to believe in:
1) Lorentz non-invariant physics.
2) quark is or can be a bound state of some "stuff".

In order to believe in some idea, say preons, physicists need to see two things (for me No1 is enough):
1) mathematically sound theory (logical consistency & explanatory power)
2) experimental evidence.
Well, regarding preons and/or Lorentz violation, we have niether (1) nor (2). So, according to Occam's razor, we are better without them.

Let's apply your logic to the neutrons and protons themselves. Back before quarks were accepted would you have argued that all known particles carry integral electric charges and therefore quarks must too? Would you have argued that all known particles can be found in a free state and therefore quarks must too?

Larger than SU(2) symmetry ,SU(3), led naturally to fractional charges. Most physicists accepted the quark model when it was first proposed
(I would have done the same thing), because
1) it is based on mathematically sound theory
2) soon after the introduction of the quark model, many experimental verifications began to appear.
So, if I was arround in 1963, I would have said what S Coleman said about the quark model:
"It is too d... successful"

It is unwise to compare "the quark model and its success" with "preons and their failures" because

1) preon models are based on mathematically "full of garbage" theories with no experimental evidence.
2) they can not even explain the need for proposing them in the first place.
3) they can not achieve their goal (they end up with more particles than it is in real life)
4) THEY ARE UGLY AND SMELL WRONG.
5) the best of them (the one that pridicts some thing) leads to wrong pridictions, therefore it is wrong.

Do you have an outline of a proof that it is impossible for a non Lorentz invariant preon model to produce Lorentz invariant bound states? Or are you saying it's impossible only because you've never heard of it?

The very fact "I never herd of it" makes this particular model one of many irrelevant garbage arround.

However, I am very interested to see how "Lorentz non-invariant" dynamics (Lagrangian) "produces" a "Lorentz invariant bound state". So, I want you to write down the Lagrangian of this model and show me how it leads to Lorentz invariant bound state. I believe you know how to use LaTex, so I will be waiting to see that Lagrangian next time you post, OK?


regards

sam

 

[CarlB]

However, I am very interested to see how "Lorentz non-invariant" dynamics (Lagrangian) "produces" a "Lorentz invariant bound state". So, I want you to write down the Lagrangian of this model and show me how it leads to Lorentz invariant bound state. I believe you know how to use LaTex, so I will be waiting to see that Lagrangian next time you post, OK?

What you're asking for is too complicated to put into a single post, nor does it belong on this thread. A first step on getting to where I described is to construct Lorentz invariant propagators from a non Lorentz invariant theory. Will you accept that as a first step or do you insist on having a whole textbook typed into a post?

By the way, regarding Bohm's opinions. You can claim whatever you want to about what the man told you etc. But why would you think he would talk to you about Lorentz invariance when you exhibit this attitude towards it? You can put whatever (self-serving) words you want to into a dead man's lips but you cannot deny his very clear writing on the subject.

Carl

 

[samalkhaiat]

What you're asking for is too complicated to put into a single post, nor does it belong on this thread. A first step on getting to where I described is to construct Lorentz invariant propagators from a non Lorentz invariant theory. Will you accept that as a first step or do you insist on having a whole textbook typed into a post?

I am happy to see the lagrangian, just the lagrangian. Is this too complicated for you? Just write to me a Lorentz non-invariant Lagrangian

By the way, regarding Bohm's opinions. You can claim whatever you want to about what the man told you etc. But why would you think he would talk to you about Lorentz invariance when you exhibit this attitude towards it? You can put whatever (self-serving) words you want to into a dead man's lips but you cannot deny his very clear writing on the subject.

By the way I never put a single word in Bohms lips. Everything I have said can be easily verified and checked.
You do need to read and understand Bohm & Hiley book. And You do need to know that discrete symmetries are not Lie type symmetries.

sam

 

[CarlB]

I know Bohm well enough to tell you that he never believed in "accidental relativity".

The quote you are answering is my statement in response to your quote:

It is IMPOSSIBLE, even for God, to distinguish between inertial frames full stop.

I never said Bohm believed in accidental relativity. You set up a straw man here.

What Bohm & Hiley said in chapter 12, regarding QM versus relativity,is the following: IF QM does not break down at some fundamental level, and IF a metric tensor field CAN BE defined on such level, then a LARGE quantum fluctuations could prevent this metric from having diagonal form, i.e. spacetime may cease to be Minkowskian and Lorentz group ceases to be fundamental.

Now, it is equally possible that it is the QM that breaks down at such level. In this case, Lorentz symmetry may continue to be fundamental. I believe, the book discusses this possibility in chapter 14.

So here's the evidence. You believe a version of what Bohm and Hiley believed. I believe a different version. You have a belief as to what is in Bohm & Hiley's book, "The Unidivided Universe". I have a different belief. What kind of experiment can we run to determine who is wrong and who is right (if either)? It seems that we should read chapter 14 and see what it says about Lorentz invariance. Should be easy enough.

I've got the book in my lap. Here's the early references to Lorentz invariance in Chapter 14: Regarding the GRW extension of QM, "Therefore it seems likely that further new developments of this approach may lead to the need to assume a deeper non-relativistic level, rather as we have had to do in our own interpretation as explained in chapter 12, section 12.8." No mention of Lorentz invariance from there until they discuss extensions of their own theory in section 14.6. I quote the last 5 paragraphs of the book:

Our proposed ontological explanation of the quantum theory has, as we have seen, also led to a certain paradox. For it implies nonlocality and this would seem to contradict relativity which is regarded as a theory that is equally as fundamental as quantum theory. But as we have seen in chapter 12, section 12.7, it is possible to propose a deeper theory of the individual quantum process which is not relativistically invariant and which nevertheless leads to Lorentz invariant consequences for all statistical results, as well as for the large scale manifest world. In this theory there is a preferred coordinate frame in which the instantaneous transmission of impulses is in principle possible, so that there is no contradiction with nonlocality for individual quantum processes. In other words, we say that underlying the level in which relativity is valid is a subrelativistic level in which it is not valid even though relativity is recovered in a suitable statistical approximation as well as the large scale manifest world.

In our discussion of this idea we have already suggested one way in which the theory might imply new experimental consequences. Thus although there is no inherent limitation to the speed of transmission of impulses in this subrelativistic level, it is quite possible that quantum nonlocal connections might be propagated, not at infinite speeds, but at speeds very much greater than that of light. In this case, as explained in chapter 12, we could expect observable deviations from the predictions of the current quantum theory (e.g. by means of a kind of extension of the Aspect-type experiment).

It would seem then that already in this case a subrelativistic level would simultaneously be one that goes beyond the current quantum theory. But the notion of a general subquantum mechanical level would have to go beyond the current quantum theory in a much more thoroughgoing way. To explore such a possibility, it is useful to consider once again the stochastic form of our ontological approach. We recall that in this approach a particle follows a trajectory that is random, but is modified by a suitable osmotic velocity along with the action of the quantum potential. At the level of Brownian motion of atoms, for example, similar random trajectories are regarded as approximations to actual trajectories in which this randomness does not prevail at indefinitely short distances. Rather there exists a characteristic length, the mean free path, below which simple causal laws begin to have a dominant effect. This free path reveals itself in many experiments, e.g. those of diffusion, conductivity of heat, etc. Similarly we may propose that in our theory there is a minimum free path below which the trajectory ceases to be random. As the atomic free path is the first sign of a 'subcontinuous' domain in which the laws of continuous matter would break down, so the free path in our trajectories would be the first first sign of a subquantum domain in which the laws of quantum theory would break down. It is implied of course that this would begin to occur for wavelengths of the order of the 'free path'.

The next sign of a breakdown of the quantum theory would be the discovery of some yet smaller dimension whose role might be analogous to the dimension of the atom in the atomic explanation of continuous matter. We do not yet know what this dimension is, but it seems reasonable to propose that it could be of the order of the Planck length, where, in any case, we can expect that our current ideas of space-time and quantum theory might well break down. The 'free path' would then be some multiple of this length.

At present further progress only seems to be possible through the use of the imagination to suggest new concepts that might permit a more precise formulation of these ideas. In this regard the situation is not very different from what it is in string theory, which is at present guided by speculative use of mathematical concepts, that also have little or no contact with experiment. As we have pointed out in section 12.8 of chapter 12, it took over 2000 years before the atomic theory of Democritus could achieve a more precise formulation. But we may reasonably hope that with the more rapid progress of science in the present era, it will take considerably less time.

In short, there is absolutely no indication of Lorentz symmetry getting saved by some sort of quantum breakdown in this book. The authors imply future experiments might show violations of Lorentz symmetry and even outline ways it could happen. The book is filled with references to the necessity of a preferred reference frame. And yet you claim to have known the authors well. What you're doing is filling another man's books with your own ideas just like you put your own ideas onto his lips. And you think that I'm the one who's disconnected from reality?

Carl

 

[samalkhaiat]

You believe a version of what Bohm and Hiley believed. I believe a different version. You have a belief as to what is in Bohm & Hiley's book, "The Unidivided Universe". I have a different belief. What kind of experiment can we run to determine who is wrong and who is right (if either)?

One experiment is to write down the Lagrangian of that Lorentz NON-INVARIANT theory you talked about, which I am still waiting to see.

Saying that "O(3) symmetry" breaks down to a "discrete symmetry" indicates clearly that your knowledge about physics and mathematics is very very poor.
So you already did run that experiment.


sam

 

[CarlB]

One experiment is to write down the Lagrangian of that Lorentz NON-INVARIANT theory you talked about, which I am still waiting to see.

You haven't mentioned anything about "The Undivided Universe" nor the opinions of Bohm and Hiley on special relativity. I have shown that your opinion: It is IMPOSSIBLE, even for God, to distinguish between inertial frames full stop. was not only not shared by all physicists, but it wasn't even shared by the physicists who taught you. And you wrote: Not just in the book, but even in private coversations, Bohm & Hiley never explained or proposed such a "future" experiment. but I showed extensive quotes from their book showing that this is not the case. Look, if you want people to believe your opinions about what opinions are shared by "all physicists", then you might try explaining how it came to be that you didn't even know the opinions of two physicists that you claim were close to you. No one can verify what David Bohm told you "one hour before he died". Anyone can verify what is written in Bohm's books, and that is compatible with what I wrote about his opinions.

Now if, after reading extensive quotes from Bohm & Hiley, you're willing to admit you were wrong about their opinions with regard to preferred reference frames, then we can continue. But if you are so stubborn that even simple things like what is in chapter 14 of "The Undivided Universe" evade you, then I have no further discussion with you. Admit your error and we will continue.

On the subject of the possibility of physical situations having more Lie symmetry at low energies than high, you wrote: "Look Carl, if you want to look for violation of some Lie symmetry, then you should look at low energy phenomena (at large length scale)." and "The correct statement is; the standard model could be an effective theory of more symmetric one. And this "deep" theory must show, in certain limit, all the symmetries of the SM."

In return, I gave you a common physical example where an apparent Lie symmetry at low energies breaks down at high energy, namely where the O(3) symmetry of the interactions of low energy photons with a cubic symmetry crystal break down to the discrete symmetry of the crystal lattice at high energies.

If you want to continue discussing physics you need to confront my example with something deeper than: "Saying that "O(3) symmetry" breaks down to a "discrete symmetry" indicates clearly that your knowledge about physics and mathematics is very very poor.

Your comment says absolutely nothing about physics or mathematics. What you've written is just an ad hominem attack of no use to anyone.

Now if you want me to comment further on this, you need to either adimt that in the example of photons in cubic crystals, an apparent continuous symmetry breaks down to a discrete symmetry at high energies, the reverse of the expected symmetry behavior of the standard model, as I claimed existed (many more examples exist). If you don't like my use of terminology, then correct the terminology. If you don't agree with the physics, then correct the physics. If you think the mathematics is wrong, the say what you think is right.

But if you really want to explain something, not just to me, but to anyone else reading this thread (perhaps your students), then lay off the ad hominem attacks. And the human memory is a treacherous thing. If you're going to argue through the use of name dropping, you need to make sure that the written record supports your memory.

Carl

 

[samalkhaiat]

You haven't mentioned anything about "The Undivided Universe" nor the opinions of Bohm and Hiley on special relativity.

Look, I have never read the book! But I DO know exactly what Bohm & Hiley did put in each chapter. YES, This well I know the two men and their "opinions".
However, I am not a "Bohmian". I don't believe in or share the same philosophical views of Bohm (or Hiley). This is why I DONOT agree with their speculations in some parts of the book.
I even have my doubts about the whole mathematical structure of (what peopel now call) Bohmian mechanics.

Bohm saw GOD in his quantum potential, but was very unhappy with the fact that his god (QP) could not account for or explain the existence of photon and other relativistic particles.
For many years, research students at Birkbeck were trying to do two things;
1) Finding the relativistic version of Bohm's equation (i.e doing what Dirac did to Schrodinger equation)
2) Deriving Bohm's Eq. from the integral Schrodiger Eq.

i\hbar \frac{\partial{\phi(p)}}{\partial{t}}= \int d(\bar{p}) H(p,\bar{p}) \phi(\bar{p})

(i.e proving that Bohm's Eq is equivalent ro Schrodinger's)

After 6 mohths of work on this program, I realized that such task is (at least for me) impossible to accomplish (still is an open question). This failure forced me to abandon my earlier interest in the interpretations of QM and choose to do my phd on the mathematical formalisim of field theory instead.
The day, I made this decision, I said to Hiley
"mathematics forces me to believe that photon and other relativistic particles are too fast for Bohm's GOD to see and explain. It seems to me that quantum potential is FUNDAMENTALLY non-relativistic concept. something that disappears completely in the relativistic domain. This together with the fact that Bohm's Eq can only be derived from the differential(x-space) Schrodinger Eq, suggests a place for Bohm theory somewhere between Newton's mechanics and Non-relativistic QM".
After that day, Hiley started introducing me to people by saying (with smile): "this is ... who has been annoying me for some time"

Now if you want me to comment further on this, you need to either adimt that in the example of photons in cubic crystals, an apparent continuous symmetry breaks down to a discrete symmetry at high energies, the reverse of the expected symmetry behavior of the standard model, as I claimed existed (many more examples exist). If you don't like my use of terminology, then correct the terminology. If you don't agree with the physics, then correct the physics. If you think the mathematics is wrong, the say what you think is right.

But if you really want to explain something, not just to me, but to anyone else reading this thread (perhaps your students), then lay off the ad hominem attacks. And the human memory is a treacherous thing. If you're going to argue through the use of name dropping, you need to make sure that the written record supports your memory.

The relavent symmetry groups of "photon" interaction (even when it interacts with cows) are SO(1,3) & U(1), NOT (S)O(3).

1) The symmetry of regular solids(crystalls) is classified by the so-called point groups. They are;
the cyclic group C_{i} and
the dihedral group D_{i} ,with i = 2,3,4 and 6.

2) the symmetry group of an atom is the rotation group SO(3).

Tiny knowledge in group theory tells us

\left(C_{i},D_{i}\right) \subset SO(1,3)

This says that symmetry groups of the macroscopic (low energy) system, the crystall, are subgroups of the symmetry group of the microscopic (high energy),(deep level) system, the atom. Isn't this what I said?
Do you want me to rephrase? OK

The above relation means that low energy "effective" theory (of crystall) is less symmetric than its corresponding high energy "deep" theory (of atom)
, apart from the words atom and crystall, this was exactly my statement.

How about another rephrase? so you understand my statement first and find "that" contradicting "example"

When atoms (small, high energy things) join to form a crystall (large, low energy thing), the symmetry group of atomic physics "breaks down" to its subgroups, i.e to the symmetry groups of crystall physics.

Eventhough my statement was about Lie symmetry groups and its Lie subgroups, your "discrete symmetry example" does support, not contradict, my statement that;
Micro-world seems to be associated with larger symmetry group than that of the Macro-world.
Do you get it now?
You should have put some efforts and understood this statement before bringing about your crystall .

Physicists had very good reason to enlarge Poincare' group and to go from
SU(2) all the way up to SU(5) & SO(10).

sam

oh, what happened to that Lorentz non-invariant Lagrangian?

 

[CarlB]

Look, I have never read the book! But I DO know exactly what Bohm & Hiley did put in each chapter. YES, This well I know the two men and their "opinions".

The book itself is the only tangible evidence of what is in the book. Your memory is intangible. I trust the book. It's quite clear. I'm amazed that you're willing to tell me what is in it without reading it, and even more amazed that you're willing to admit it.

The memory plays tricks on all of us. People believe what they want to believe. The written word is far better evidence.

Isn't this what I said?

Your physics is correct, but you still talk around the example. In your answer, you've completely avoided discussing the subject at hand, which is the difference between the low energy behavior of photons in crystals and the high energy behavior of photons in crystals. Let me repeat it again.

Consider the physics of photons in cubic symmetry crystals. Low energy photons see no crystal at all. For them, the symmetry of the region they operate in is the full Lie group of rotations and translations in 3 dimensions. It is only as the energy of a photon increases that it begins to interact with the crystal and discovers that the symmetry is not so complete.

Instead of this example, you are defeating a straw man. Yes, I agree that the symmetry of an atom is greater than the symmetry of a crystal. But the example is not the atom. The example is the photons and the photons alone. The crystal, and its atoms, are only providing the background for the photon, they are not of concern.

Physicists had very good reason to enlarge Poincare' group and to go from SU(2) all the way up to SU(5) & SO(10).

Well, the proton didn't decay, did it. If symmetry were the solution to all elementary particle problems there wouldn't be all those string theorists running around loose out there.

oh, what happened to that Lorentz non-invariant Lagrangian?

You can have it after you admit that (a) Bohm and Hiley very clearly wrote in favor of a preferred reference frame in the book "The Undivided Universe", and (b) the photons in cubic system crystals provide a physical example of how a system (in this case the photons in cubic crystals) can have a Lie symmetry broken at high energies rather than low. Until we get through these, no more. This is enough.

I am glad to see you back. I've got some more to talk with you about, I'll put it in another post.

Carl

 

[CarlB]

Since the standard model is only an effective theory, any of its symmetries could be accidental.

The correct statement is; the standard model could be an effective theory of more symmetric one. And this "deep" theory must show, in certain limit, all the symmetries of the SM.

Here is a quote from Lee Smolin's latest book, "The Trouble with Physics":

(p 315) One of the great seers is Holger Bech Nielsen of the Niels Bohr Institute. He was an inventor of string theory, and he has many other key discoveries to his credit. But for many years he has been isolated from the mainstream for advocating what he calls random dynamics. He believes that the most useful assumption we can make about the fundamental laws is that they are random. Everything we think of as intrinsically true, such as relativity and the principles of quantum mechanics, he thinks are just accidental facts that are emergent from a fundamental theory so beyond our imagining that we might as well assume that its laws are random. His models are the laws of thermodynamics, which used to be based on principles but now are understood as the most likely way that large numbers of atoms in random motion will behave. This may not be right, but Nielsen has come remarkably far in his antiunification program.

Here are some Holger Nielsen preprints:

http://www.arxiv.org/find/hep-th/1/au:+Nielsen_H/0/1/0/all/0/1

One that reads directly on our discussion is this one:

Derivation of Poincare Invariance from general quantum field theory
C.D. Froggatt, H.B. Nielsen
Annalen der Physik, Volume 14, Issue 1-3 , Pages 115 - 147
Special Issue commemorating Albert Einstein
Starting from a very general quantum field theory we seek to derive Poincare invariance in the limit of low energy excitations. We do not, of course, assume these symmetries at the outset, but rather only a very general second quantised model. Many of the degrees of freedom on which the fields depend turn out to correspond to a higher dimension. We are not yet perfectly successful. In particular, for the derivation of translational invariance, we need to assume that some background parameters, which a priori vary in space, can be interpreted as gravitational fields in a future extension of our model. Assuming translational invariance arises in this way, we essentially obtain quantum electrodynamics in just 3 + 1 dimensions from our model. The only remaining flaw in the model is that the photon and the various Weyl fermions turn out to have their own separate metric tensors.
http://www.arxiv.org/abs/hep-th/0501149
http://www3.interscience.wiley.com/cgi-bin/abstract/109884430/ABSTRACT

By the way, this is NOT my example of how one can obtain Poincare invariance from a QFT that does not possesses it. To get MY example, you have to play nice by admitting that Bohm and Hiley wrote a book that very clearly presented their belief that there is a preferred reference frame, and by admitting that photons in crystals are an example of a Lie symmetry that breaks at high energy rather than low.

Carl

 

[samalkhaiat]

We are not yet perfectly successful. In particular, for the derivation of translational invariance, we need to assume that some background parameters,

DID YOU READ THIS

By the way, this is NOT my example of how one can obtain Poincare invariance from a QFT that does not possesses it

Write down that Lagrangian which you do not know or have.

you have to play nice by admitting that Bohm and Hiley wrote a book that very clearly presented their belief that there is a preferred reference frame,

NO, They suggested a line of thoughts which they admit it could be wrong, because it is based on speculations.

and by admitting that photons in crystals are an example of a Lie symmetry that breaks at high energy rather than low.

School kids know that when they talk about photons in crystalls, in chairs and in cows the symmetry is the Lorentz's SO(3,1).

I can only admit that you have shown everybody that your knowledge about physics and math is infinitesmal. I will be here from time to time to let everybody knows this fact about you.

bye