Thread: Special relativity is harder to understand

1. Now that I think I know a little more about QM, I am finding that Special relativity (SR) is harder to grasp.

I am familiar with the geometry of 4D Minkowski spacetime and the Lorenz transformation that keeps the Minkowski metric invariant. So in geometry SR is very clear and beautiful.

But in terms of physics I don’t think we know what is going on in SR, like how light manages to travel in constant speed in all reference frames. We know light as EM or particle/wave or wavefunction quite well now, but for light as constancy in speed, we still know nothing about it.

If I were Nature and have to solve the issues of relativity in motions, it would be much simpler to just have an universal rest frame, but Nature instead instruments this wicked light scheme. This suggests the issue of relativity in motion is far deeper that it appears, that is to say, the concept of motion is not what we think it is.

Also, it is not just light behaves this way, all force carriers like gluons or graviton if there is such a thing, also behave like light.

I am in the middle of analyzing the basic concepts involved in SR and I can already see some conceptual lapse in our current SR formulation.

For instance, I think we also need Newton’s first law in formulating SR, at least for the reference frame business. Newton’s first law actually has very deep meaning, as deep as QM and GR if not more so.

I think the concept of reference frame is too convoluted that clouds over other important issues.

I am very surprised that not much attention is paid to SR in terms of its interpretation, perhaps because the Minkowski/Poincare geometry explanation is too successful?

These are some of my thoughts and comments. I have some intriguing thoughts but they are kind of still in fluctuation.

So the challenge still remains after so many years: can you in any way to characterize the fact that light is constancy in speed in all reference frames. can you say anything besides saying it is a fact. Can you even imagine what this fact looks like.

And I throw in a more specific question: if light is in a reference frame, what light would see?
Yes I know the Lorenz transform prohibits this, but can you think of a way to circumvent Lorenz?

2.

3. Originally Posted by trilosohpical
Yes I know the Lorenz transform prohibits this, but can you think of a way to circumvent Lorenz?
There is no way of "circumventing Lorentz" (not "Lorenz" as you write). You need to come to grips with this FACT, since it is backed up by thousands of experiments.

4. Originally Posted by trilosohpical
I am familiar with the geometry of 4D Minkowski spacetime and the Lorenz transformation that keeps the Minkowski metric invariant. So in geometry SR is very clear and beautiful.
It is pretty cool, isn't it.

But in terms of physics I don’t think we know what is going on in SR
You have just described, in general terms, what is "going on".

like how light manages to travel in constant speed in all reference frames. We know light as EM or particle/wave or wavefunction quite well now, but for light as constancy in speed, we still know nothing about it.
What is there to know? It is a postulate of relativity, confirmed by the correctness of the theory.

Also, it is not just light behaves this way, all force carriers like gluons or graviton if there is such a thing, also behave like light.
Not all force carriers, only the massless ones.

For instance, I think we also need Newton’s first law in formulating SR, at least for the reference frame business. Newton’s first law actually has very deep meaning, as deep as QM and GR if not more so.
As far as I know there is no contradiction between Newton's first law and SR. In fact, Newton's first law is important to SR: it is what defines an inertial frame of reference.

I think the concept of reference frame is too convoluted that clouds over other important issues.
How is it convoluted? It seems fairly simple to me. And what issues does it could?

All this seems to cast doubt on your initial claim of familiarity with the theory.

5. Originally Posted by trilosohpical
But in terms of physics I don’t think we know what is going on in SR, like how light manages to travel in constant speed in all reference frames. We know light as EM or particle/wave or wavefunction quite well now, but for light as constancy in speed, we still know nothing about it.

Originally Posted by trilosohpical
I am familiar with the geometry of 4D Minkowski spacetime and the Lorenz transformation that keeps the Minkowski metric invariant. So in geometry SR is very clear and beautiful.

6. Originally Posted by xyzt
Originally Posted by trilosohpical
Yes I know the Lorenz transform prohibits this, but can you think of a way to circumvent Lorenz?
There is no way of "circumventing Lorentz" (not "Lorenz" as you write). You need to come to grips with this FACT, since it is backed up by thousands of experiments.
people, please read more carefully what I said. I have repeated said light speed is a fact.
Now, who says light has to be subject to lorenz transform if light is on a reference frame?
since when being on a frame is equivalent to be subject to lorenz transform?
there are zillions of kind of transformation in nature, that does not mean one must be subject to these transform.

7. Originally Posted by trilosohpical
Originally Posted by xyzt
Originally Posted by trilosohpical
Yes I know the Lorenz transform prohibits this, but can you think of a way to circumvent Lorenz?
There is no way of "circumventing Lorentz" (not "Lorenz" as you write). You need to come to grips with this FACT, since it is backed up by thousands of experiments.
people, please read more carefully what I said. I have repeated said light speed is a fact.
Now, who says light has to be subject to lorenz transform if light is on a reference frame?
Turns out that it is YOU who needs to read carefully:
-it is LorenTz and not "Lorenz". A sure sign of crackpottery is misspelling his name
-there is no such thing as "light on a reference frame".

since when being on a frame is equivalent to be subject to lorenz transform?
there are zillions of kind of transformation in nature, that does not mean one must be subject to these transform.
The above is pure garbage.

8. For instance, I think we also need Newton’s first law in formulating SR, at least for the reference frame business. Newton’s first law actually has very deep meaning, as deep as QM and GR if not more so.
As far as I know there is no contradiction between Newton's first law and SR. In fact, Newton's first law is important to SR: it is what defines an inertial frame of reference.

I think the concept of reference frame is too convoluted that clouds over other important issues.
How is it convoluted? It seems fairly simple to me. And what issues does it could?

All this seems to cast doubt on your initial claim of familiarity with the theory.[/QUOTE]

i think you need to read more carefully. what you said about the newton's first law is exactly my point about SR's conceptual lapse because the reference frame SR uses implicitly relies on the notion of rest that must come from newton'e first law. i don't think you have realized that point even though you seem to know newton's first law pretty well.

now you seem to know something about reference frame, so maybe you can tell us what exactly reference frame means in SR context. don't forget there are choice words like observer, and since there is observer, there should also be observable, tell us what these words mean.

9. Good news and bad news.
Good: He's not blogging this time.
Bad: He's no smarter nor more coherent.

10. -there is no such thing as "light on a reference frame".
can you tell us why?

let's see, because if you do a lorenz transform there will be 1/0, right?

but nobody is asking to do a lorenz transform on light.
you are basically making up your own story and try to use your story to criticize me.

11. Originally Posted by Dywyddyr
Good: He's not blogging this time.
Bad: He's no smarter nor more coherent.

I am interested to see why I am not coherent, care to elaborate?

12. let's see, because if you do a lorenz transform there will be 1/0, right?

but nobody is asking to do a lorenz transform on light.
You supplied an answer, attributed it to xyzt, and then argued against it. That's a classical strawman.

13. Moved to Personal theories.

14. Originally Posted by trilosohpical
So in geometry SR is very clear and beautiful.
Yes, and that is all there is to it. SR is a geometric model of flat space-time.

We know light as EM or particle/wave or wavefunction quite well now, but for light as constancy in speed, we still know nothing about it.
In flat space-time, all inertial observers see the same vacuum ground state , regardless of their states of relative motion; since the speed of light is a function of vacuum permittivity and permeability, it is hence obvious that all observers measure the same c. All that SR does is explore the consequences of this fact - the constancy of the speed of light is a postulate for SR, not a prediction or consequence of it, just like everyone seeing the same laws of physics is a postulate rather than a consequence. If your issue is with why the speed of light is constant, then you need to seek the answer in QFT, not SR.

But in terms of physics I don’t think we know what is going on in SR
The upshot is that you are missing the point. SR only explores the consequences of ( i.e. the relationship of space and time in flat space-times ), but not the reasons for the constancy of c. And in that it is very successful.

15. Originally Posted by trilosohpical
[i think you need to read more carefully. what you said about the newton's first law is exactly my point about SR's conceptual lapse because the reference frame SR uses implicitly relies on the notion of rest that must come from newton'e first law.
There is no notion of "rest" in either SR or Newton's laws. There is only relative motion.

now you seem to know something about reference frame, so maybe you can tell us what exactly reference frame means in SR context.
A set of coordinates for measuring position. I thought you said you were familiar with SR. It doesn't sound like it.

16. As someone with pretty limited understanding (but a toe hold I hope) of SR and far far less of QFT who understands that c is in fact constant but puzzles as to "why" can I draw comfort that the question is addressed (and hopefully resolved) in QFT ?

Just to clarify what Markus seems to be saying -that an intuitive understanding of a constant value of c to all observers is available provided one is prepared to put in the legwork and the study?

Up to this point I believed that this was just an observable fact that we had to accommodate willy nilly - a bit like an unwelcome guest at a gathering (now can I view it as a new friend that I have yet to become properly acquainted with?)

17. Originally Posted by geordief
Up to this point I believed that this was just an observable fact that we had to accommodate willy nilly
I think you can view it that way: it is just a fact about the universe; from which we can deduce things like relativity theory.

Or you can view it the other way round: given the universe appears to have the geometry described by relativity, then a constant speed of light is an inevitable consequence of that.

18. Maxwells equations for electromagnetism give a universal speed for light waves. What Einstein did was to say what would be the result if this was true in all frames of reference. The constant speed of light is an observable fact but it also has a theoretical basis.

19. Originally Posted by PhDemon
Maxwells equations for electromagnetism give a universal speed for light waves. What Einstein did was to say what would be the result if thus was true in all frames of reference.
Yep. That's another way of looking at it. It is just the result of the values for vacuum permittivity and permeability.

But why do they have those values ...

20. Originally Posted by Strange

Yep. That's another way of looking at it. It is just the result of the values for vacuum permittivity and permeability.

But why do they have those values ...
The deeper question - which is what I think the OP actually means to ask, but gets back-to-front - is what the underlying structure of the vacuum really is, and hence why these constants actually are constant for all inertial observers. That, however, is outside the scope of SR.

21. .

22. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
So in geometry SR is very clear and beautiful.
Yes, and that is all there is to it. SR is a geometric model of flat space-time.

We know light as EM or particle/wave or wavefunction quite well now, but for light as constancy in speed, we still know nothing about it.
In flat space-time, all inertial observers see the same vacuum ground state , regardless of their states of relative motion; since the speed of light is a function of vacuum permittivity and permeability, it is hence obvious that all observers measure the same c. All that SR does is explore the consequences of this fact - the constancy of the speed of light is a postulate for SR, not a prediction or consequence of it, just like everyone seeing the same laws of physics is a postulate rather than a consequence. If your issue is with why the speed of light is constant, then you need to seek the answer in QFT, not SR.

But in terms of physics I don’t think we know what is going on in SR
The upshot is that you are missing the point. SR only explores the consequences of ( i.e. the relationship of space and time in flat space-times ), but not the reasons for the constancy of c. And in that it is very successful.
thank you very much!

this is the kind of argument I am looking for.
you say that "In flat space-time, all inertial observers see the same vacuum ground state , regardless of their states of relative motion"
but why inertial observers can still be in different reference frames? - that is Newton's first law but i don't know how it is translated in qm context.
what is then the meaning of lorentz transformation?
i think you are pretty close to what i am thinking, but you are still missing something.
finally, is there an explanation out there on the light speed need to be maximal?
it is one thing to be constancy, but to be maximal is a different story.
it just occurs to me today why light speed should also be maximal, and i don't mean to satisfy the lorentz formulae, it has far deeper meaning.

23. Originally Posted by trilosohpical
but why inertial observers can still be in different reference frames?
Because they are in motion relative to one another (hence, "regardless of their states of relative motion").

what is then the meaning of lorentz transformation?
It translates between one (inertial) reference frame and another.

24. Originally Posted by Strange
Originally Posted by trilosohpical
but why inertial observers can still be in different reference frames?
Because they are in motion relative to one another (hence, "regardless of their states of relative motion").

what is then the meaning of lorentz transformation?
It translates between one (inertial) reference frame and another.
Strange, you are quoting me out of context here.
I was asking these question on the context of Markus Hanke statement that
"In flat space-time, all inertial observers see the same vacuum ground state , regardless of their states of relative motion

I think the vacuum ground state Markus referring to here is the class of inertial state, is that right Markus?

25. I am also interested to know how QFT is able to deduce that light speed needs to be constancy, because if you know that you should be able to construct the 4D sapcetime and should also have the some idea of quantizing the spacetime. What stop people from doing that? not having the correct path integral?

Anybody cares to shed some light on how QFT is able to derive at light speed?
I don't know much about QFT but I know enough about Feynman's path integral to know what QFT should be about.

26. Originally Posted by trilosohpical
but why inertial observers can still be in different reference frames?
Being in different reference frames means they are in a state of relative motion.

what is then the meaning of lorentz transformation?
Lorentz transformations are just how the measurements in different frames are related. More technically, they are the elements of the matrix group which leaves the metric invariant.

finally, is there an explanation out there on the light speed need to be maximal?
That is due to the geometry of space-time; the speed of light represents a null surface emanating from every event - this is just the usual light cone. Anything outside that light cone is not causally connected to the original event; but again, light tracing out null geodesics is a postulate rather than a consequence of SR.

it is one thing to be constancy, but to be maximal is a different story.
Actually, SR does not forbid space-like separations between events ( the mathematics of this work out just fine ) at all - them being unphysical is a postulate, because empirically no tachyonic particles have ever been observed. It is in fact possible to generalise SR in a way to properly describe tachyons and their behaviour, but the results have consequences which can hardly be considered reasonable in any sense of the word, thus their existence is discounted by most theoretical physicists. Most notably, their existence would allow real, physical paradoxes to be constructed, which isn't good.

27. Originally Posted by trilosohpical
I am also interested to know how QFT is able to deduce that light speed needs to be constancy
QFT doesn't do that, it only says that observers in uniform relative motion see the same vacuum ground state. This automatically means that permittivity and permeability must be the same too.
Unfortunately QFT is not ( yet ) my area of expertise, so I cannot give you the mathematical proof of this.

28. Originally Posted by Strange
Originally Posted by trilosohpical
[i think you need to read more carefully. what you said about the newton's first law is exactly my point about SR's conceptual lapse because the reference frame SR uses implicitly relies on the notion of rest that must come from newton'e first law.
There is no notion of "rest" in either SR or Newton's laws. There is only relative motion.

now you seem to know something about reference frame, so maybe you can tell us what exactly reference frame means in SR context.
A set of coordinates for measuring position. I thought you said you were familiar with SR. It doesn't sound like it.
These are some of the finer and subtle points in SR which I think need more careful analysis and that is really the purpose of this post.
But I don't think I am up to the task of explaining all the subtleties involved, you have to think a bit harder and more careful to see the hidden meanings.

29. Originally Posted by trilosohpical
These are some of the finer and subtle points in SR which I think need more careful analysis and that is really the purpose of this post.
But I don't think I am up to the task of explaining all the subtleties involved, you have to think a bit harder and more careful to see the hidden meanings.
There are no hidden meanings and subtleties, SR is simple and straightforward geometry, and just a special case of GR. In fact, SR is probably one of the simplest and yet most powerful models we have in today's physics. You just need to be careful to distinguish between the postulates of the model, and its resulting predictions.

30. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
but why inertial observers can still be in different reference frames?
Being in different reference frames means they are in a state of relative motion.

what is then the meaning of lorentz transformation?
Lorentz transformations are just how the measurements in different frames are related. More technically, they are the elements of the matrix group which leaves the metric invariant.

finally, is there an explanation out there on the light speed need to be maximal?
That is due to the geometry of space-time; the speed of light represents a null surface emanating from every event - this is just the usual light cone. Anything outside that light cone is not causally connected to the original event; but again, light tracing out null geodesics is a postulate rather than a consequence of SR.

it is one thing to be constancy, but to be maximal is a different story.
Actually, SR does not forbid space-like separations between events ( the mathematics of this work out just fine ) at all - them being unphysical is a postulate, because empirically no tachyonic particles have ever been observed. It is in fact possible to generalise SR in a way to properly describe tachyons and their behaviour, but the results have consequences which can hardly be considered reasonable in any sense of the word, thus their existence is discounted by most theoretical physicists. Most notably, their existence would allow real, physical paradoxes to be constructed, which isn't good.
thanks again.
I also happen to reached the similar understanding of what you just said, but via my own way of thinking, just using the concepts necessary in SR and QM.
So if the state of motion is an observable, but why nobody is treating it that way, that is to say, why no QM come out of it?
This morning I just realized I know of a way to QM the spacetime.
It is really two 3D geometries and then being combined into a single 4D Minkowski via a circle group which I think is what people call the gauge.
the path integral will be tricky because it should do the probability distribution as well as meshing time into 4d spacetime.

In my first post, I also raised question of light on a rest frame (like inertial frame of Newton's first law sense), can you comment on this question?
I don't see any physics prohibits this.
because I see a lot of interesting things in that setting.

31. Originally Posted by trilosohpical
Anybody cares to shed some light on how QFT is able to derive at light speed?
Like I said, QFT is not my area of expertise, but here is a possible way to do this ( without reference to the QED Lagrangian ). Start with the vector potential A, and define a 2-form F such that

Now define a corresponding current density vector J

as usual. You can now calculate the exterior derivative of the dual of the 2-form F, and find

Now take the dual once again and get

In vacuum, the current density identically vanishes, so we get

which is just the usual electromagnetic wave equation in vacuum. The d'Alembert operator automatically guarantees that the wave propagates at exactly c - in fact it cannot do anything else without violating Maxwell's equations.

32. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
Anybody cares to shed some light on how QFT is able to derive at light speed?
Like I said, QFT is not my area of expertise, but here is a possible way to do this ( without reference to the QED Lagrangian ). Start with the vector potential A, and define a 2-form F such that

Now define a corresponding current density vector J

as usual. You can now calculate the exterior derivative of the dual of the 2-form F, and find

Now take the dual once again and get

In vacuum, the current density identically vanishes, so we get

which is just the usual electromagnetic wave equation in vacuum. The d'Alembert operator automatically guarantees that the wave propagates at exactly c - in fact it cannot do anything else without violating Maxwell's equations.
thanks, that is the beauty of math.

33. Originally Posted by trilosohpical
So if the state of motion is an observable, but why nobody is treating it that way, that is to say, why no QM come out of it?
I am not certain what you mean. Standard SR does not use the notation of states and observables; this wouldn't make any sense, because all of Relativity is purely classical, so if written in terms of operators, those would have a continuous spectrum of eigenvalues, unlike in QM. It is far easier to directly use coordinates.

This morning I just realized I know of a way to QM the spacetime.
Quantising space-time is straightforward enough - you just triangulate it into discreet simplexes to obtain a simplical approximation which reduces to a smooth manifold in the classical limit. In SR the deficit angle of those simplexes, once arranged together, is exactly zero, so space-time is flat; in GR you get non-vanishing deficit angles, so you get a space-time with non-vanishing Riemann tensor. This is called Regge calculus. The problem is not to "quantise" space-time itself, but to do it in a way so as to obtain length/volume/curvature operators with the correct discrete spectra, while recovering standard Regge calculus ( and hence the GR equations ) in the classical limit. Loop quantum gravity is one such attempt, causal dynamical triangulations is another. Which one will turn out to be the correct one remains to be seen.

the path integral will be tricky because it should do the probability distribution as well as meshing time into 4d spacetime.
If you want to use path integrals, then your phase space will be the space of all possible geometries ( metrics ), and the formal partition function integral will look something like

where I denote "EH" for the discrete version of the Einstein-Hilbert action, and D[g] is some appropriate functional of the metric. If you expand this expression, you will find that even for trivial choices of D[g] this becomes an extremely difficult path integral to solve. There are numerical approximations in existence, though.

In my first post, I also raised question of light on a rest frame (like inertial frame of Newton's first law sense), can you comment on this question?
There is no frame of reference in which light can be at rest - hence "light" is not a valid frame of reference in the Theory of Relativity. Alternatively, you can see that by considering that there is no possible Lorentz transform that brings you from any frame of your choosing into the "frame" of a photon - it's a mathematical impossibility, and if such a transformation did exist, it wouldn't leave the metric invariant, which violates the basic postulates of relativity.

I don't see any physics prohibits this.
Physically, this simply means that you can never reach the speed of light, no matter how hard and for how long you accelerate. If that weren't so, the laws of physics couldn't be the same for everyone, and hence our universe would look very different indeed.

34. [QUOTE=Markus Hanke;554519]
Originally Posted by trilosohpical

In my first post, I also raised question of light on a rest frame (like inertial frame of Newton's first law sense), can you comment on this question?
Alternatively, you can see that by considering that there is no possible Lorentz transform that brings you from any frame of your choosing into the "frame" of a photon
Very good point and now I really see.

I just realized that I am confusing a lot of people here by the use of SR.
The SR I am referring to here is my way of understanding of SR, so it has a lot of my own additional stuff in it.

I am not good with GR, maybe its time to move up a notch from SR to GR.
Currently, to me, GR is about the correlations (as in the energy-momentum tensor) of some physics quantities and being invariant of their localizations under all kinds of transformations.
I have strange idea about localization vs coordinate, some kind of subtleties I have yet to work out in detail in terms of their construction.
My way of understanding physics is very primitive, basically I ask Nature what is the problem and how to deal with it.
But I know enough of math to understand what physics is saying in math language.

35. Originally Posted by trilosohpical
I am not good with GR, maybe its time to move up a notch from SR to GR.
If I can offer my advice here - you need to thoroughly understand SR first, before you can even begin to worry about GR.

Currently, to me, GR is about the correlations (as in the energy-momentum tensor) of some physics quantities and being invariant of their localizations under all kinds of transformations.
GR is a geometric theory of gravity - it explains gravity as being a manifestation of the geometry of space-time, which in turn depends on sources of energy-momentum as described by the energy-momentum tensor. GR is also about the global relationships between observers in the resulting curved space-times, which, unlike in SR, is highly non-trivial. The difference between SR and GR is simply that SR deals only with flat space-times and hence cannot handle any cases where gravity plays a role.

Both GR and SR make extensive use of tensors; these are geometric objects which have the very convenient property of being invariant under coordinate transformations - physically, that means an equation written with tensors will have the same form for all observers, no matter where they are and how they move relative to each other. In other words - tensor equations are completely independent of the choice of coordinates. This principle is called general covariance.

36. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
So if the state of motion is an observable, but why nobody is treating it that way, that is to say, why no QM come out of it?
I am not certain what you mean. Standard SR does not use the notation of states and observables; this wouldn't make any sense, because all of Relativity is purely classical, so if written in terms of operators, those would have a continuous spectrum of eigenvalues, unlike in QM. It is far easier to directly use coordinates.
If you think of a rest frame, aka Lorentz transform, aka motion state as a class, instead of an individual object in that state, you will see my point of view.

37. Originally Posted by trilosohpical
If you think of a rest frame, aka Lorentz transform, aka motion state as a class, instead of an individual object in that state, you will see my point of view.
I do understand your point of view, and I am sure it is possible to define such a formalism ( "Lorentz operators" acting on some motion state vector to yield a new state vector ), but I fail to see the advantage or justification, since these operators would have a continuous eigenvalue spectrum. It is far easier to just use coordinates and their transforms.

38. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
If you think of a rest frame, aka Lorentz transform, aka motion state as a class, instead of an individual object in that state, you will see my point of view.
I do understand your point of view, and I am sure it is possible to define such a formalism ( "Lorentz operators" acting on some motion state vector to yield a new state vector ), but I fail to see the advantage or justification, since these operators would have a continuous eigenvalue spectrum. It is far easier to just use coordinates and their transforms.
To appreciate the notion of motion, we need to understand the notion of rest which is inherent in the concept of reference frame.
I know that an object being at rest in a reference frame is self evident, and that is precisely the point of me saying hidden meaning in SR.
Only one sees the meaning in rest can then appreciate the meaning of motion and the meaning of Newton's first law.

39. Originally Posted by trilosohpical
To appreciate the notion of motion, we need to understand the notion of rest which is inherent in the concept of reference frame.
I know that an object being at rest in a reference frame is self evident, and that is precisely the point of me saying hidden meaning in SR.
Only one sees the meaning in rest can then appreciate the meaning of motion and the meaning of Newton's first law.
A "reference frame" is just a particular choice of coordinates, so there is nothing mysterious or hidden about this. Relative motion arises only if one compares reference frames.

40. Originally Posted by trilosohpical
To appreciate the notion of motion, we need to understand the notion of rest which is inherent in the concept of reference frame.
I know that an object being at rest in a reference frame is self evident, and that is precisely the point of me saying hidden meaning in SR.
Only one sees the meaning in rest can then appreciate the meaning of motion and the meaning of Newton's first law.
Can you explain what you think the "hidden meaning" in rest is?

41. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
To appreciate the notion of motion, we need to understand the notion of rest which is inherent in the concept of reference frame.
I know that an object being at rest in a reference frame is self evident, and that is precisely the point of me saying hidden meaning in SR.
Only one sees the meaning in rest can then appreciate the meaning of motion and the meaning of Newton's first law.
A "reference frame" is just a particular choice of coordinates, so there is nothing mysterious or hidden about this. Relative motion arises only if one compares reference frames.
yes there lies the difference between me and other people and I am truly at lost in explaining myself because I can't explain something that is self evident.
The only thing I can say is that the Newton's first law is very deep, as deep as QM.

42. Originally Posted by trilosohpical
yes there lies the difference between me and other people and I am truly at lost in explaining myself because I can't explain something that is self evident.
If you can't explain what you mean, e.g. mathematically, then it isn't really science, is it?

43. Originally Posted by Strange
Originally Posted by trilosohpical
To appreciate the notion of motion, we need to understand the notion of rest which is inherent in the concept of reference frame.
I know that an object being at rest in a reference frame is self evident, and that is precisely the point of me saying hidden meaning in SR.
Only one sees the meaning in rest can then appreciate the meaning of motion and the meaning of Newton's first law.
Can you explain what you think the "hidden meaning" in rest is?
One way to explain it to say think like Bach when dealing with motion, I think Newton must also thought of this kind of question.
But in Newton's time it was easy because he assumed a global static rest frame.

44. Originally Posted by trilosohpical
One way to explain it to say think like Bach when dealing with motion, I think Newton must also thought of this kind of question.
But in Newton's time it was easy because he assumed a global static rest frame.
I think you might have missed the word "explain" in my question ...

Suggesting I "think like Bach" is not terribly helpful. (1. he is dead. 2. he was a musician. 3. I have no idea what he thought about motion. 4 ... well, you get the idea)

45. Originally Posted by Strange
Originally Posted by trilosohpical
yes there lies the difference between me and other people and I am truly at lost in explaining myself because I can't explain something that is self evident.
If you can't explain what you mean, e.g. mathematically, then it isn't really science, is it?
And who are you?
God of science?

46. Originally Posted by Markus Hanke

Quantising space-time is straightforward enough - you just triangulate it into discreet simplexes to obtain a simplical approximation which reduces to a smooth manifold in the classical limit. In SR the deficit angle of those simplexes, once arranged together, is exactly zero, so space-time is flat; in GR you get non-vanishing deficit angles, so you get a space-time with non-vanishing Riemann tensor. This is called Regge calculus. The problem is not to "quantise" space-time itself, but to do it in a way so as to obtain length/volume/curvature operators with the correct discrete spectra, while recovering standard Regge calculus ( and hence the GR equations ) in the classical limit. Loop quantum gravity is one such attempt, causal dynamical triangulations is another. Which one will turn out to be the correct one remains to be seen.
Very interesting.
why is obtaining length/volume/curvature operators with the correct discrete spectra should become part of requirement for quantization of spacetime?
Now I can see the issue.
What is the right physical entity as the target of quantization, what make people think that length/volume/curvature are the observables?
But how can you bring in boundary for the path integral if you choose variables like length or volume?
because we are not just dealing with the time like dimension here, the exponential can easily go crazy if the dimension is not right.

So the idea of this simplical approach is to try to produce some kind of geometrical probability out of geometrical space, and there lies the problem for normalization.
because usually geometrical probability arises from some specific problem domain, not just generalized space.
It's a beautiful way of thinking but I am not sure it is the right physics.

47. OK, here is a scenario that I don't hear people taking.

Say I am on an inertial trajectory in spacetime. the Minkowski metric square value is say 10.
I can do all crazy Lorentz transformations, but that won't change the metric value.

How can I jump to a different trajectory so that the metric square value say become 15?

I know I am not using the right jargon but basically I as a spacetime traveler wants to change the value of metric square of my own.
What is the physics act that can achieve that?
I have to accelerate?

48. Originally Posted by Markus Hanke
Lorentz transformations are just how the measurements in different frames are related. More technically, they are the elements of the matrix group which leaves the metric invariant.
The invariance of the metric is what defines the Lorentz transformations, and in particular, makes the Lorentz transformations so special. Otherwise, one can legitimately apply arbitrary transformations, as is done in general relativity.

Originally Posted by Markus Hanke
Actually, SR does not forbid space-like separations between events ( the mathematics of this work out just fine ) at all - them being unphysical is a postulate, because empirically no tachyonic particles have ever been observed. It is in fact possible to generalise SR in a way to properly describe tachyons and their behaviour, but the results have consequences which can hardly be considered reasonable in any sense of the word, thus their existence is discounted by most theoretical physicists. Most notably, their existence would allow real, physical paradoxes to be constructed, which isn't good.
It should be noted that timelike intervals and spacelike intervals are distinguished from each other by the unequal splitting of the metric into positive and negative coefficients.

49. Originally Posted by trilosohpical
I can't explain something that is self evident.
You are not making much sense, to be honest; if it is self-evident, then no explanation is needed. So far as I am concerned, I do not see any deep or hidden issues with the concept of "at rest" in SR. You are either at rest in a particular frame of reference, or you are not.

why is obtaining length/volume/curvature operators with the correct discrete spectra should become part of requirement for quantization of spacetime?
They have to have the correct spectra so that GR is recovered in the classical limit, or else the model is not physically meaningful.

What is the right physical entity as the target of quantization
Yes, that is the big question so far as quantum gravity is concerned - what is the correct underlying system of degrees of freedom ? We don't know the answer as per yet. It could be the spin network of LQG, it could be the 4-simplexes of CDT, or perhaps something like a CFT Lagrangian. There are many approaches being investigated at present.

what make people think that length/volume/curvature are the observables
They are the quantities that we can physically measure, but whether or not they are the "observables" of quantised gravity remains to be seen. These operators arise naturally in the context of LQG, which is why I mentioned them.

But how can you bring in boundary for the path integral if you choose variables like length or volume?
No, in the most popular approaches ( LQG and CDT ) the variables in the path integral are not length and volume, but the metric itself.

So the idea of this simplical approach is to try to produce some kind of geometrical probability out of geometrical space
So far as I understand it, there are two vastly different approaches here :

1. Keep space-time smooth and continuous, but treat the metric as a variable in a wave function, so that geometries of space-time become the elements of an appropriately chosen phase space
2. Quantise space-time itself

Number (1) is done using the Wheeler-deWitt equation :

with the operator H being a Hamiltonian constraint. This of course begs the question what the appropriate constraint needs to be, and how to solve the resulting equations. The approach (2) is what is done in CDT and LQG, whereas it should be mentioned that CDT is more of a mix between (1) and (2).

It's a beautiful way of thinking but I am not sure it is the right physics.
At present, no one is sure about anything so far as quantum gravity is concerned; it is an area of ongoing and very active research.

50. Originally Posted by trilosohpical
How can I jump to a different trajectory so that the metric square value say become 15?
The metric is preserved only between inertial frames - if you want to change the separation between your events as determined by an observer, you can make him trace out a world line that corresponds to an accelerated frame of reference. SR can still handle this just fine, but you can no longer use Lorentz transformations, because the metrics of inertial and non-inertial observers are different.

What is the physics act that can achieve that?
I have to accelerate?
Yes, precisely.

51. [QUOTE=Markus Hanke;554775]

You are not making much sense, to be honest; if it is self-evident, then no explanation is needed. So far as I am concerned, I do not see any deep or hidden issues with the concept of "at rest" in SR. You are either at rest in a particular frame of reference, or you are not.
let’s say I have some kind of conviction on this. But as for the argument it is still evolving.

Basically I want to mimic QM, so I have the idea of daulity of rest vs motion, similar to particle-wave daulity.

I know a rest frame is a class of motion and I want it to be an observable in the QM sense for spacetime.

Initially I thought the lorentz transform is its operator, but now I know that is wrong.

Now I think the operator has to be force.

Force is 2nd order and that is why i think einstein’s tensors work in spacetime, because these tensors represent force and are operators for the rest frames. In other words, tensors collapse motions into a particular class of rest frame.

So here is the idea, the observable is rest frame, the operator is force, the state is the class of rest with a particular metric length and the einganvalue should the metric length. the wavefunction that results will be gravitons

Tell me if this approcach make sense to you.

I take back my ealier comments about getting geometric probabiltity out of general space.
I now understand this simpletical approach. Because the space has already filled with pre-constructed elements like trangles and they will naturally produce some kind of probability in terms how do they interact among them, like pump in vertics or on the sides etc.

I also see the point of string theroy now. It is the same idea, that is to have some pre-defined premitive structure and let them interact and there will be some probability pattern rise natrually out of it.

Still, what is the right premitive constructs is the key question.

52. Originally Posted by trilosohpical
because these tensors represent force and are operators for the rest frames
Tensors aren't forces, they are multilinear maps which take vectors and 1-forms into real numbers.

Tell me if this approcach make sense to you.
I'm afraid it doesn't. My advice to you would be to perhaps invest the time and thoroughly study a good text on General Relativity, such as Misner/Thorne/Wheeler.

53. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
because these tensors represent force and are operators for the rest frames
Tensors aren't forces, they are multilinear maps which take vectors and 1-forms into real numbers.

Tell me if this approcach make sense to you.
I'm afraid it doesn't. My advice to you would be to perhaps invest the time and thoroughly study a good text on General Relativity, such as Misner/Thorne/Wheeler.
yeah. i know it won't be that simple.
I am not fond of heavy math like differential geometry and that is why i try to avoid GR.
my strength is in analysis of basic concept and logic and constructs.

one thing i was wondering though, how did einstein come up with that energy-momentum tensor, i mean the correct arrangement of elements in tensor?
the diagonal is easy since it must be minkowski metric, but for other elements, what is the theory for their placement.

54. Originally Posted by trilosohpical
I am not fond of heavy math like differential geometry and that is why i try to avoid GR.
Well, I suppose it depends what goal you set yourself. You can't fully understand GR without at least some of the mathematics; but what you can do is focus on the main mathematical concepts, and disregard the finer details. I know it isn't easy, but then again, no part of modern physics is.

how did einstein come up with that energy-momentum tensor
I am not much of a historian, but I am pretty sure that the energy-momentum tensor was known before Einstein; he wasn't the one who came up with this. I do know for certain that the mathematical notion of "tensor" in general was known long before Einstein.

There is deeper significance to this object, it isn't just an arbitrary arrangement of components - without going too much into the details, it turns out that the energy-momentum tensor is the geometric property of a system which remains conserved under space-time translations. The important concept here is Noether's theorem, which connects symmetries of a system with conserved quantities - the energy-momentum tensor is the conserved Noether current of space-time translation invariance, for instance.

the diagonal is easy since it must be minkowski metric
No, it isn't - this tensor on its own doesn't have anything to do with the metric. In terms of physical meaning, the component represents energy density, the other diagonal components represent pressure across a unit surface.

but for other elements, what is the theory for their placement.
The formal theory is the aforementioned conserved Noether current, but a more tangible explanation is probably this one :

55. Thanks.
This statement clicks with me;
the energy-momentum tensor is the geometric property of a system which remains conserved under space-time translations

One thing I don’t understand is the source of correctness in GR, because to me, GR is an extension of Newtonian in the sense it does not take part in the construction/creation process of things like what happen in QM. How can GR account for the energies caused by spins?
But GR seems to be correct.
This suggests that the source of gravity is very deep and I suspect it has do to with some kind of counting on motion states.

The reason I think gravity is related to motion is that I think mass has a duality in the form of inertia vs gravity. Inertia is related to motion by Newton’s first and second laws, since gravity is the dual of inertia, then gravity should also relates to motion.

I know gravity means curvature in geometry but I think it can also have physics meaning in terms of process or instrumentation.

56. Originally Posted by trilosohpical
One thing I don’t understand is the source of correctness in GR
The source of correctness of general relativity comes from the principle that all the equations are form-invariant with respect to general coordinate transformations, and that the quantities of GR are derived from this principle.

Originally Posted by trilosohpical
because to me, GR is an extension of Newtonian in the sense it does not take part in the construction/creation process of things like what happen in QM.
General relativity is classical because it assumes counterfactual definiteness, contrary to quantum theory.

Originally Posted by trilosohpical
How can GR account for the energies caused by spins?
The standard theory of general relativity can be generalised further such that particular quantities that are zero in the standard theory are not generally zero in the general theory. One such quantity is known as the torsion tensor, which is said to represent spin density.

Originally Posted by trilosohpical
But GR seems to be correct.
This suggests that the source of gravity is very deep and I suspect it has do to with some kind of counting on motion states.
It's about symmetry. Entropic theories of gravity have been invalidated by interferometry experiments where one path is at a different gravitational potential to the other path.

Originally Posted by trilosohpical
Inertia is related to motion by Newton’s first and second laws, since gravity is the dual of inertia, then gravity should also relates to motion.
Inertia is about symmetry of the laws of physics with respect to Lorentz transformations.

57. Originally Posted by KJW
Entropic theories of gravity have been invalidated by interferometry experiments
That's interesting, I was under the impression that the general concept of entropic gravity is still considered viable, and that active research is being done in that field. Do you have a reference to the experiment you are alluding to ?

58. Originally Posted by trilosohpical
But GR seems to be correct.
It is correct in the sense that it explains the available empirical data very well, at least in the macroscopic domain. At the same time we know that it is incomplete, because it is a purely classical theory and cannot account for any quantum effects.

59. Originally Posted by Markus Hanke
Originally Posted by KJW
Entropic theories of gravity have been invalidated by interferometry experiments
That's interesting, I was under the impression that the general concept of entropic gravity is still considered viable, and that active research is being done in that field. Do you have a reference to the experiment you are alluding to ?
I was hoping that Entropic gravity might provide the link but it didn't. I eventually found the article titled "Measurement of quantum states of neutrons in the Earth’s gravitational field" (the main text is behind a paywall)¹. Without going into details, the argument is that entropic gravity would cause a loss of coherence that was not observed in the experiment.

¹ I actually come across the experiment as a news item on another forum.

60. Originally Posted by KJW
Without going into details, the argument is that entropic gravity would cause a loss of coherence that was not observed in the experiment.
Ok, thank you. I don't immediately see how entropic gravity would cause this, but then again, my QM knowledge is pretty limited, so I take the author's word for it. Does this mean we should consider the idea of entropic gravity as being obsolete ?

61. Originally Posted by Markus Hanke
Originally Posted by KJW
Without going into details, the argument is that entropic gravity would cause a loss of coherence that was not observed in the experiment.
Ok, thank you. I don't immediately see how entropic gravity would cause this, but then again, my QM knowledge is pretty limited, so I take the author's word for it. Does this mean we should consider the idea of entropic gravity as being obsolete ?
It all depends on how good one regards the arguments on either side. My personal view is that entropic gravity is wrong, so I am biased in this regard. As for how entropic gravity causes loss of coherence, consider what entropic gravity actually means. In other words, consider the nature of entropy, and how this is incompatible with coherence.

62. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
But GR seems to be correct.
It is correct in the sense that it explains the available empirical data very well, at least in the macroscopic domain. At the same time we know that it is incomplete, because it is a purely classical theory and cannot account for any quantum effects.
great point. GR is correct, but it is not good at providing new leads into something that we don't know like what QM is able to.

63. Originally Posted by KJW
Originally Posted by Markus Hanke
Originally Posted by KJW
Entropic theories of gravity have been invalidated by interferometry experiments
That's interesting, I was under the impression that the general concept of entropic gravity is still considered viable, and that active research is being done in that field. Do you have a reference to the experiment you are alluding to ?
I was hoping that Entropic gravity might provide the link but it didn't. I eventually found the article titled "Measurement of quantum states of neutrons in the Earth’s gravitational field" (the main text is behind a paywall)¹. Without going into details, the argument is that entropic gravity would cause a loss of coherence that was not observed in the experiment.

¹ I actually come across the experiment as a news item on another forum.
this is what i expected. the counting of motion states that i mentioned earlier is a kind of ensemblic counting that should collapse the ensemble, which is what people call decoherence.
i think our current QM is missing the concept of ensemble collapse, in the sense of wavefucntion collapse, calling it deconherence is really cloud the issue.

this is my another post that i talked about counting and ensemblic counting:
Want to talk quantum mechanics interpretations?

i think these are important concepts that are still missing in our current physics.

64. Originally Posted by KJW

Originally Posted by trilosohpical
Inertia is related to motion by Newton’s first and second laws, since gravity is the dual of inertia, then gravity should also relates to motion.
Inertia is about symmetry of the laws of physics with respect to Lorentz transformations.
I think this is the key difference I have with everyone here.
yesterday i went through Newton's 3 laws and i reaffirmed my believe that the concept of inertia which i call at rest is far more deeper than SR or even GR.
I have some general idea of what is going with gravity.
there are two kinds of dualities
inertia vs gravity
at rest vs relativity in motion.

these are the foundation duality that should derive and drive other things.
but instead, we let the notion of relativity takes over the whole reasoning process which hides and clouds these foundation issues.

since relativity is correct, everybody think the business is over, problem solved.
but is not.
unless we understand these two dualities, we are nowhere near in understanding gravity.

i believe these two dualities are equivalent, the key is how to make such equivalence connection.
i also believe that Newton's 3 laws have in principle addressed the issues.

65. now that i went though Newtonian second time, let me explain why the notion and fact of at rest/inertia frame is so deep.

I am standing on earth at rest, but the earth is moving around the sun and sun is moving and on and on.
So basically nothing can be at rest.
Now in Newtonian, there was ether the ultimate at rest, so the notion of at rest was fine.
But now we let relativity take over and deny the ether, but we still assume the notion of at rest on newtonian sense.
The notion of at rest is fine in Newtonian world, but it is definitively not ok in relativity world, and that is i called conceptual lapse in SR.

don't get me wrong, i am not saying SR incorrect, but SR has has missed some important concept in its formulation.

The question is then, what is the physics that can account for the notion and fact that there can be arbitrary at rest in anywhere in the universe?

66. Originally Posted by Markus Hanke
Originally Posted by KJW
Entropic theories of gravity have been invalidated by interferometry experiments
That's interesting, I was under the impression that the general concept of entropic gravity is still considered viable, and that active research is being done in that field. Do you have a reference to the experiment you are alluding to ?
I think the traditional thermodynamic way of counting may not capture all the details, because the notion of "motion state" here is very different.

67. Originally Posted by trilosohpical
The question is then, what is the physics that can account for the notion and fact that there can be arbitrary at rest in anywhere in the universe?
It's called general covariance. It basically means you are free to choose the coordinate systems you want to use, without affecting the form of the laws of physics. Since coordinate systems are arbitrary, then so is the notion of "at rest", because it is frame dependent.

68. in GR, when you do path integral, do you just sum over the paths of one particular metric value, or sum over the sum of path for all metric values?
for instance the metric value for light is 0.
for other non-zero metric values say, 10, i think you need to sum over paths on the metric values form 0 to 10.
and i think the metric value need to be quantize overwise you will have the similar problem that leads to ultra-violate problem of light that finally gives us the Planck h.

i think there needs a similar constant like h in QM in GR, but it is for the unit of metric length quantization not unit of energy.

69. i just realized that now i understand why in QM the position is not quantized.

70. Originally Posted by trilosohpical
in GR, when you do path integral, do you just sum over the paths of one particular metric value, or sum over the sum of path for all metric values?
We don't normally use path integrals in standard GR, since it is purely classical.

71. ok, i see the difference. in feynman's path integral, there is no notion of measure since qm has no concept of 'distance'.
but in GR, there is lorentz measure/metric, you have to use that as the measure in the partition function, right?

but if you don't quantize the metric length, you will not be able to normalize the integral.

72. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
The question is then, what is the physics that can account for the notion and fact that there can be arbitrary at rest in anywhere in the universe?
It's called general covariance. It basically means you are free to choose the coordinate systems you want to use, without affecting the form of the laws of physics. Since coordinate systems are arbitrary, then so is the notion of "at rest", because it is frame dependent.
for some reason this statement fails to click with me.

i think the issue here is more complicated if we consider QM. for instance when an electron is in wave, can we have rest frame on that electron?

73. Originally Posted by trilosohpical
i think the issue here is more complicated if we consider QM.
Yes, it will be more complicated, because of the probabilistic nature of QM; it will no longer be possible to determine with definiteness what the state of motion of a particle is at a given time. It is also not possible to determine exactly where it is, which is one of the reasons why a quantised version of gravity is non-renormalizable.
However, GR itself is purely classical, so no such problem arises within its domain of applicability.

can we have rest frame on that electron?
No, not in the sense of the way GR does it. It will require a completely new formalism.

but if you don't quantize the metric length, you will not be able to normalize the integral.
I must admit that I am not privy to the finer details of renormalisation theory, since I have not studied this area yet in any detail. Thus I can't really comment on the above.

74. [QUOTE=Markus Hanke;555452]
Originally Posted by trilosohpical

but if you don't quantize the metric length, you will not be able to normalize the integral.
I must admit that I am not privy to the finer details of renormalisation theory, since I have not studied this area yet in any detail. Thus I can't really comment on the above.
i am reevaluating the meaning of lorentz metric value.
i have a new general idea of what lorentz metric value should mean, but there are still details to thing through.

i think that the lorentz metric value has meaning only in certain very specific physics process which i would call instrumentation. the one process i am thinking of is the process of meshing the separate 3d space and time into a 4d minkowski spacetime (think gauge). all qm instrumentation has to go through this process thus qm operators are always lorentz invariant.

but i don't see other use of the lorentz metric and the lorentz metric value is always 0 in QM instrumentation.

i think the cosmology constant people talk about in GR is the fluctuation of this lorentz metric value.
basically the metric value determines the proportioonal ratio of the space and time in 4d minkowski spacetime.

what is confusing is that there is also a local version of lorentz metric valuation instrumentation, because each lorentz transform also remesh the propotionality of space and time and that is why you can have time dilation and length contraction, but this local remeshing will not change the metric value since lorentz transform preserve the metric.

so we basically 2 kinds of meshing instrumentation, one used in QM which always has value of 0 (don't know how it works on an electron) and one in SR/GR which is local within the lorentz transformation group that won't change the lorentz metric value.

since these two instrumentations are very important and are missing in our current physics, i want to formally call them as:
QM/global ST metricazation - for the QM process that mesh the original 4d spacetime.
SR/local ST metricazation - for a local remesh process due to lorentz transformation that give us time dilation and length contraction.

for QM/global metricazation, the resulting space and time ratio is always 1, the distance in space = the distance in time. This ratio has very deep meaning, all force or observable(?) should have this ratio.

and for the local ST metricazation, the resulting space and time ratio which i think can be proportionally derived from v/c, v being the space length and time length will be proportional to c-v.

I want to quality a bit to say that the QM metricazation is just one of processes in the QM instrumentation.

75. by the way i can say all these things because i think i finally figured out what is going in qm.
do you want a hint?
think quaternion.
it all about quaternions, but in a very interesting and strange way.

76. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
i think the issue here is more complicated if we consider QM.
Yes, it will be more complicated, because of the probabilistic nature of QM; it will no longer be possible to determine with definiteness what the state of motion of a particle is at a given time. It is also not possible to determine exactly where it is, which is one of the reasons why a quantised version of gravity is non-renormalizable.
However, GR itself is purely classical, so no such problem arises within its domain of applicability.

can we have rest frame on that electron?
No, not in the sense of the way GR does it. It will require a completely new formalism.

but if you don't quantize the metric length, you will not be able to normalize the integral.
I must admit that I am not privy to the finer details of renormalisation theory, since I have not studied this area yet in any detail. Thus I can't really comment on the above.
my brain is spinning trying to imagine rest frames all over the distributed space of an electron wave.
but i am not sure.

this is a test of whether qm trumps over SR/GR or the other way around or they are of equal.

the question here is: does Newton's first law transcends or is irrelavent to QM ?

my current feeling is that newton's first law which is equivalent of gravity is of equal to QM, they are somehow a duality of something of higher order.

77. Originally Posted by trilosohpical
my brain is spinning trying to imagine rest frames all over the distributed space of an electron wave.
The concept of rest frame doesn't make sense for this scenario, that's one of the main issues we have with quantum gravity.

this is a test of whether qm trumps over SR/GR or the other way around or they are of equal.
I would expect these to be two different approximations for the same overarching theory, being a model that can describe all fundamental interactions.

the question here is: does Newton's first law transcends or is irrelavent to QM ?
Newtonian mechanics are purely classical, so I wouldn't worry too much about it so far as QM is concerned.

78. Originally Posted by Markus Hanke
Originally Posted by KJW
Without going into details, the argument is that entropic gravity would cause a loss of coherence that was not observed in the experiment.
Ok, thank you. I don't immediately see how entropic gravity would cause this, but then again, my QM knowledge is pretty limited, so I take the author's word for it. Does this mean we should consider the idea of entropic gravity as being obsolete ?
The reason entropic gravity may work is that by Newton’s first law every object in the universe can have its rest frame, thanks to spin which ensures that every object has some motion state. Thus we can have a generic way of partitioning and counting of objects by their rest frames which are representation of their motion states.

The tricky thing though, each rest frame basically is a reference/perspective for the entire universe, by resting on one particular object, all other objects has to do a local Lorentz transform to recalculate their motion state based on that rest frame.

to see why such a generic/uniform way of partitioning/counting is fundamental, just think of QM as a mechanics of using a generic/uniform way of counting everything, and that is counting the states (in wavefunction).

So the fundamental of physics boils down to how to devise a partitioning so that you can count thing, making sure not to over or under count.

79. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
my brain is spinning trying to imagine rest frames all over the distributed space of an electron wave.
The concept of rest frame doesn't make sense for this scenario, that's one of the main issues we have with quantum gravity.

this is a test of whether qm trumps over SR/GR or the other way around or they are of equal.
I would expect these to be two different approximations for the same overarching theory, being a model that can describe all fundamental interactions.

the question here is: does Newton's first law transcends or is irrelavent to QM ?
Newtonian mechanics are purely classical, so I wouldn't worry too much about it so far as QM is concerned.
I know some of the stuff I am saying here is heresy, but let me assure you I know what I am saying.

My current reasoning (still subject to change) is that QM and GR are equal and parallel, that is they are a duality of the same thing.

80. Originally Posted by trilosohpical
Originally Posted by Markus Hanke
Originally Posted by trilosohpical
my brain is spinning trying to imagine rest frames all over the distributed space of an electron wave.
The concept of rest frame doesn't make sense for this scenario, that's one of the main issues we have with quantum gravity.

this is a test of whether qm trumps over SR/GR or the other way around or they are of equal.
I would expect these to be two different approximations for the same overarching theory, being a model that can describe all fundamental interactions.

the question here is: does Newton's first law transcends or is irrelavent to QM ?
Newtonian mechanics are purely classical, so I wouldn't worry too much about it so far as QM is concerned.
I know some of the stuff I am saying here is heresy, but let me assure you I know what I am saying.

My current reasoning (still subject to change) is that QM and GR are equal and parallel, that is they are a duality of the same thing.
I just realized that I am wrong in using Newton's first law for at rest, because Newton assumed absolute rest frame and I don't.

So let me now formally formulate as follow:

The law of at rest:
every physics entity can be at rest on a rest frame such that if there is no force act upon it, it will remain at rest.

notice that:
i say rest frame instead of reference frame - noting is inferred of reference or observer, but such will be some of natural results of this law.
i choose the word entity instead of object - to open up a little bit of ontological ground.
i don't say physics entity is in what form, particle or wave, but such entity do need to be of physics.
i don't say inertia or mass - because both should naturally rise from the physics of this law when interacting with other entities.

81. Since I am in the mode of reformulation of natural law, let me try to reformulate the entire theory of relativity.

So here is my first attempt to formulate the theory of relativity that should include both SR and GR:

1. The law of at rest:
Every physics entity can be at rest on a rest frame such that if there is no force act upon it, it will remain at rest.

2. The law of motion:
Every physics entity belongs to some motion class; every motion class is in reference to a rest frame.

3. The law of applicability
the law of at rest and the law of motion are applicable to both QM and Newtonian.

Notice that:
in the law of at rest:
i say rest frame instead of reference frame - noting is inferred of reference or observer, but such will be some of natural results of this law.
i choose the word entity instead of object - to open up a little bit of ontological ground.
i don't say physics entity is in what form, particle or wave, but such entity do need to be of physics.
i don't say inertia or mass - because both should naturally rise from the physics of this law when interacting with other entities.

In the law of motion:
I don’t say law of physics is in the same form for all rest frame.
I don’t say speed of light constency.
I don’t define what is motion, I am debating if need to define as not at rest.
While I have some confidence the law of at rest will give rise to inertia, I am not 100% sure if gravity will rise fully from the combined laws of at rest and motion.

the law of applicability:
this law helps to bring in some dynamics/materials.
the inclusion of QM will bring test and meaning to the notion of "every" and of "physics entity".
the law applicability means this theory is of equal footing with QM.

The difference of this formulation vs Einstein’s is this one is very specific about the INDIVIDUALITY in terms of its motion state. This kind of formulation intends to help to bring out all possible partitioning (since we have the notion of individuality and its state) and counting instrumentation. This approach is in line with the general concept in QM.

When I try to formulate the law of motion, I had no idea. It just came out of blue and was formulated in about 5 minutes. I don't know why the idea came but there it is.
the law of applicability was not in the original formulation.
the law of applicability is needed because the other two laws are meta physics of template and potential and need real world dynamics and materials.

82. Originally Posted by trilosohpical
I just realized that I am wrong in using Newton's first law for at rest, because Newton assumed absolute rest frame and I don't.
No, Newton does not assume an absolute rest. The notion of absolute rest was discarded by Galileo. It should be noted that relativity started with Galileo, not Einstein.

83. i do not expect people to understand the theory of relativity I formulated above, but just hope that you don't think i am crazy or somehting.

I am wordering if anyone is familiar with graviton - becaue my theory above predicts graviton - by some argument based on the law of rest.

the question is this:

we know spatial length can contract due to lorentz transformation.

if there is gravity wave, does inertia material also contact?
what happen if spatial contraction is out of wack with the material contraction?

has this been an issue in gravity wave study?

i don't think i have ever heard this kind of talking before, but it should be an issue if there is graviton.
i just come up this issue because i am trying to understand what graviton would do for the local metricazation, and i see this issue.

In SR, i think we grosses over the two kind of contractions, as the single length contraction, but if there are graviton, there should be material contraction as well.

84. Originally Posted by trilosohpical
My current reasoning (still subject to change) is that QM and GR are equal and parallel, that is they are a duality of the same thing.
Although it's not entirely clear to me what this means, I regard QM and GR as complementary. That is, they describe different aspects of reality, and they are both required for reality to be "complete".

85. Originally Posted by trilosohpical
we know spatial length can contract due to lorentz transformation.
But this is not a physical contraction. It is simply a change in perspective.

86. i just realized what this question mean.

87. Originally Posted by KJW
Originally Posted by trilosohpical
My current reasoning (still subject to change) is that QM and GR are equal and parallel, that is they are a duality of the same thing.
Although it's not entirely clear to me what this means, I regard QM and GR as complementary. That is, they describe different aspects of reality, and they are both required for reality to be "complete".
very good point.
the statement you quoted was kind of prematural - it was before i came up with my formulation. but after i formulated my theory and thought over the consequence, i began to feal that i need both QM and GR to be complete. initially there are only 2 laws, and then i added the third law.

i might try to come up a formulation that can include QM as well.
I was thinking that an hour ago, but the problem is that QM is diverse and more process oriented.

plus, being an intuitionist, i do want to include QM processes in the laws, like the glaobal and local metricazation i mentioned in post #73.

there will be some interesting asymmetries if i can put together laws that deal both QM and GR.

but i also have the feeling that the 3 laws i stated above is actually good enough for everything, since it indirectly uses both qm and newtonian.

88. Originally Posted by KJW
Originally Posted by trilosohpical
I just realized that I am wrong in using Newton's first law for at rest, because Newton assumed absolute rest frame and I don't.
No, Newton does not assume an absolute rest. The notion of absolute rest was discarded by Galileo. It should be noted that relativity started with Galileo, not Einstein.
that is good to know.
but i am just not going to quote Newton in my theory, Newton is just a bad word in this context.

89. is anybody familair with particle physics?
when people calculate strong and weak force and motion in uncleai, do they find very small decrepency in mass/energy?

90. Originally Posted by KJW
Originally Posted by trilosohpical
we know spatial length can contract due to lorentz transformation.
But this is not a physical contraction. It is simply a change in perspective.
no, the length contraction is real and physical.

91. speaking of those paradox, i am not really buying the official explanation.
i haven't had the time to take a really careful analysis.

92. everything clicked this morning when i woke up. the picture of how gravity rise came to me. and the formulation for QM and even the entier physics also come to me.

but ffirst let explain how inertia and gravity rise from my theory.

the law of at rest says every entity can be at rest. to be at rest means being the reference frame for the entier universe. but the law of motion says every motion is meaningful to only one particular reference frame.

so here rises naturally a probability setting of too many reference frames available but only one of them to be used for defining motion.

since every entity is candidate reference frame, there need a process to sweep thgough all entity and calculate and deeploy the probability weight on each of them, and such process/instrumentation will be the gravity wave.

the probability distributtion will naturally favor the region with more entities and that will be the effect of gravitation since it favors the spot of more entity/material (how exactly that translates into gravity pull, still need some work)

that spot of entity/material thus more probability amplitude will give rise the notion of center of inertia.

inertia can rise out of single particle/wave, the situation is bit dicy and i don't want to going there right now.

93. Originally Posted by trilosohpical
no, the length contraction is real and physical.
Length contraction is a coordinate effect; in its own rest frame, the ladder never changes, neither does the barn. And the official resolution of the paradox seems perfectly reasonable to me.

94. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
no, the length contraction is real and physical.
Length contraction is a coordinate effect; in its own rest frame, the ladder never changes, neither does the barn. And the official resolution of the paradox seems perfectly reasonable to me.
Since two very knowledgable persons all say i am wrong, then I must be wrong.
I am not good in details and this shows.

95. Wow, a breath of fresh air, someone posting in Personal Theories who actually takes notice of what other people post Good on yer...

96. I have finished in formulating the theory for QM.
and i don't see the source that can give rise to probability.
i have the feeling that the laws of at rest and of motion are probably THE fundamental source for all the probabilistic behavior in QM.

97. Originally Posted by PhDemon
Wow, a breath of fresh air, someone posting in Personal Theories who actually takes notice of what other people post Good on yer...
I did not post on personal theories. someone moved my post to here.
welcome to the thread, care to have some comment on my theory?

98. OK here is my theory of QM

Definitions:
1. physicas instrunmentation – the embodyment of physics processes that result in some physics effect.
2. Metricazation - a physics process to encode/embed a measure in some physics quantility.
3. ST Metricazation - a metricazation on space and time that combines spatial and temporal in a ratiorized measure.
4. ST Equality Metricazation - a particular ST metricazation in which spatial and temporal have equal weight.
5. Localization – the process to assign ST Metricized values to a coordinate system.
6. Locatation – the process to assign non-metricized values to a coordinate system.
7. Observable - a physics entity without any metricazation.

The Principle of Particle Wave Duality
1. Physics entity may or may not subject to ST Metricazation.
2. Physical object having ST Metricazation is called particle.
3. Physics entity with no metricazation is called wave.
4. Particle localizes in localizationalized coordinate system.
5. Wave is expressed in locatationalized coordinate system.

The Principle of Quantization
physical quantity belonging to observable is quantized.

The Law of Global/QM Metricazation (Lorentzian invariance):
The QM instrumentation aims to achieve some physical metricazation and tends to favor the ST Equality Metricazation for localization.

The Law of Measurement
Observable can be measured and the act of measurement turns the underlying physics entity into a measured physical object.

The Law of Uncertainty (HUP)
The measurement on observable is subject to a certain limitation.

1. There are only three laws and two of them have to do with measurement.
2. The particle wave duality is a principle, not law – we want to explain the phenomenon rather than pin down its behavior.
3. The definitions of particle and of wave give another characterization of particle-wave duality.
4. The explanation of localization vs locatation applied to particle and wave gives yet another characterization of particle-wave duality.
5. The notion of physics instrumentation as the whole deal that can bring us some physics result or reality.
6. the notion of metricaztion is also very important since it gives explanation of particle-wave duality, a key feature of QM.
7. the ST Equality metricazation is the lorentz metric but here we emphasize that this measure take equal part of space and time to mesh into a 4d spacetime measure.
8. Notice the difference between localization and locatation, one with physics measure and one withou

i don't like the word locatation, can you sugget a better word?

note1:
i am still debating if i should say something about quantization. what stops me is whether put it as law or as a principle.
since i put p-w duality as a principle and since quantization seems of equal weight of p-w, i don't want to tip the balance.
also it is a lot freer to say things as principle then to pin things down as a law.

Note2:
Ok i have reached decision. quantization is a principle, ie, it should arise naturally from other existing laws.
this is so because i intend to bring the law of rest and motion into the whole theory and that will give rise probability which will naturally induce p-w and quantization.

Note4:
compare with the elegance of the 2 laws for relativity, this version of QM looks quite overloaded.
I think I said too much, especially on the particle-wave thing.
the localization is probably also an overkill.
observable also need some improvement.
the metricazation, I don't know, i like it, and it is the only kind of dynamic law there.

99. Originally Posted by trilosohpical
Originally Posted by PhDemon
Wow, a breath of fresh air, someone posting in Personal Theories who actually takes notice of what other people post Good on yer...
I did not post on personal theories. someone moved my post to here.
welcome to the thread, care to have some comment on my theory?
Well it is a "personal theory" in that it is not mainstream physics so the move was justified. I'm no expert in GR or SR but from my limited understanding it seems to me you are adding unnecessary complications and the unphysical idea of a "rest frame". I don't know enough to comment further than that but listen to Markus and KJW and you won't go far wrong. I was just impressed you are taking on board their criticisms, most posters who come up with their own theory or interpretation don't

100. Originally Posted by trilosohpical
OK here is my theory of QM
To be perfectly honest - I completely lost you here now. You seem to be shooting into a hundred directions at once, and I can no longer follow what it actually is you are trying to say.

101. Originally Posted by Markus Hanke
Originally Posted by trilosohpical
OK here is my theory of QM
To be perfectly honest - I completely lost you here now. You seem to be shooting into a hundred directions at once, and I can no longer follow what it actually is you are trying to say.
yeah, the QM formulation is a bit radical.
It is just that my brain is in the mode for formulating theories and I don't want to lose it since it will take some effort to get into that kind of mode.
I am almost finished, just have to formulate something for the Newtonian and that would be it for the whole physics.

But what do you think of the law of at rest and motion?
Do you think they make some sense in general?
I know there are details you would object to, like light can be on a rest frame.
I put the notion of at rest as a law (instead of a principle) because i want to believe that nature is consistent.

These two laws are very powerful and hopeful when I am done formulating general theories I can spend some time to derive some SR/GR related issues so we can test my theories.

and also if you have any comment on my interpretation of that Lorentz metric value.
my feeling is that the cosmology constant is the small fluctuation on the Lorentz metric value, which for some reason always tends to 0.
You are right, I was all over the place, I thought I had some good idea about it now I could not remember. Hopefully something will come back to me on this Lorentz metric value.

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