Does length contraction imply a superposition of particles? [answered: no]

[34student]

4 minutes ago, MigL said:

Just about everything you've said.
And people have been telling you for two pages already, but you simply ignore them and go on.
That's no way to learn anything ...

I am always open to learning.  Contrary to what you are saying, I understand the basics of GR.  I learnt about SR in university 10 years ago, and I have been reading about it ever since.  I would really really like to know what I have said about GR that is wrong on this thread.

[Phi for All]

44 minutes ago, 34student said:

I would really really like to know what I have said about GR that is wrong on this thread.

So I'll mention (AGAIN) that you're wrong about length contraction not being observer dependent. And I still don't think you understand that observers seeing the same thing in different frames are NOT seeing different positions. When these concepts are mentioned, you dodge and dance and throw out red herrings about block universes or whatnot.

IOW, it's like you have a huge gap in your knowledge that you're ignoring by pacing around it instead of trying to fill it in. 

[beecee]

1 hour ago, 34student said:

I am always open to learning.  Contrary to what you are saying, I understand the basics of GR.  I learnt about SR in university 10 years ago, and I have been reading about it ever since.  I would really really like to know what I have said about GR that is wrong on this thread.

I have never done any course or real study of SR/GR, but what I have learnt is that space ( length) and time are interchangeable and relative. Afterall isn't that why its called relativity?

3 hours ago, swansont said:

Length is not a physical object. Neither is time. They are relevant and scientific.

Certainly true, but then again, does something need to be physical to be determined as real? Length, breadth, height, time, space, are all relevant, scientific and applicable to what they are referring to. And in that respect, real, at least imho. 

Edited December 14, 2021 by beecee

[34student]

36 minutes ago, Phi for All said:

So I'll mention (AGAIN) that you're wrong about length contraction not being observer dependent.

Yes, it would definitely appear that length contraction is observer dependent.  I know that there is a lot of evidence and theory to support this claim.  I know this.

However, when I take GR further, I see that observation and frames of reference don't really exist in any physical way.  There doesn't seem to be a direct mechanical explanation for how an observer or frame of reference causes this length contraction.

Even worse, frames of reference do no even seem to physically exist in GR even though we use them and need them to support the theory of GR.

 

[beecee]

2 hours ago, 34student said:

True.  But nonphysical entities do not cause anything physical to happen.  They can't by their nature. 

The warping and curvature of spacetime, by mass/energy, causes light to follow geodesic paths and such phenomena as gravitational lensing.

3 minutes ago, 34student said:

There doesn't seem to be a direct mechanical explanation for how an observer or frame of reference causes this length contraction.

The interchangebility of space and time.  https://www.physicsoftheuniverse.com/topics_relativity_spacetime.html#:~:text=Thus%2C space and time are,approaching the speed of light.

[34student]

3 minutes ago, beecee said:

The warping and curvature of spacetime, by mass/energy, causes light to follow geodesic paths and such phenomena as gravitational lensing.

Cause and effect are very strong indicators that something is physical.

You mention spacetime.  Matter causes a spacetime curvature, so we are half way there.  And, spacetime curvature also affects matter.  It has a cause and it has an effect; it is physical.

[beecee]

2 minutes ago, 34student said:

Cause and effect are very strong indicators that something is physical.

Space and time (like length, breadth, and height) are certainly not physical...I thought you agreed with that. Yet they (spacetime) warp, twist, curve in the presence of mass/energy.

5 minutes ago, 34student said:

You mention spacetime.  Matter causes a spacetime curvature, so we are half way there.  And, spacetime curvature also affects matter.  It has a cause and it has an effect; it is physical.

 That still doesn't make spacetime ( or space and time) physical.

 

[swansont]

45 minutes ago, beecee said:

Certainly true, but then again, does something need to be physical to be determined as real? Length, breadth, height, time, space, are all relevant, scientific and applicable to what they are referring to. And in that respect, real, at least imho. 

That’s the point. “real” (as in physical) is not required to be relevant, observable (as in measurable), and scientific, despite the claim.

[beecee]

4 hours ago, swansont said:

Length is not a physical object. Neither is time. They are relevant and scientific.

You in reply............

3 hours ago, 34student said:

True.  But nonphysical entities do not cause anything physical to happen.  They can't by their nature.  How can a frame of reference have a physical effect on anything?  The contraction simply exists with or without a frame of reference.  The same goes for the noncontracted.  They both just are as they are.

 

[34student]

25 minutes ago, beecee said:

The warping and curvature of spacetime, by mass/energy, causes light to follow geodesic paths and such phenomena as gravitational lensing.

The interchangebility of space and time.  https://www.physicsoftheuniverse.com/topics_relativity_spacetime.html#:~:text=Thus%2C space and time are,approaching the speed of light.

Yes, I understand that space and time are interchangeable.

Edited December 14, 2021 by 34student

[swansont]

3 hours ago, 34student said:

What I said is very well known and understood.  I am surprised that you do not know that.

A muon being shaped like a worldline is not “well known” and not a true statement.

 

3 hours ago, 34student said:

True.  But nonphysical entities do not cause anything physical to happen.  They can't by their nature.  How can a frame of reference have a physical effect on anything? 

It doesn’t have a physical effect. That’s your persistent misconception. Length contraction does not involve stress or strain or compression or any physical effect.

A length is shorter when measured from a moving frame.

3 hours ago, 34student said:

 Yes, that would be what GR demonstrates for us.  But there are implications to that.  One implication being that the matter in the square can not be in the same location as the matter in the rectangle, which tells us that there must be some kind of superposition in position.

No, it means you continue to misunderstand what superposition is, and what length contraction entails.

 

[34student]

6 minutes ago, beecee said:

Space and time (like length, breadth, and height) are certainly not physical...I thought you agreed with that. Yet they (spacetime) warp, twist, curve in the presence of mass/energy.

 That still doesn't make spacetime ( or space and time) physical.

 

Of course it does.  What more can you ask for than for it to have causal properties, and in a predictable manner yet?

 

Distance, however, seems nonphysical IMO.  It is like asking if nothing exists.  Well it kind of does but it also doesn't.

[MigL]

The 'duration' and 'length' of an event, in relativity, is equivalent to the projection on the spatial and temporal axis, of its rest frame ( proper ) length and duration.
This projection is different for different observers, depending on their position on the spatial/temporal axis. IOW, depending on the speed ( and vice versa ).

The frame has no physical effect, nor does it change anything directly.
It is simply the point of view of the observer, taking his circumstances into consideration.
It is similar to measuring your shadow in a North facing frame, as opposed to a south facing frame. In the first you will measure your shadow to be very long because the sun is at your back, while in the second, you will be facing the sun , and will see little, or no shadow.

[beecee]

2 minutes ago, 34student said:

Of course it does.  What more can you ask for than for it to have causal properties, and in a predictable manner yet?

 Space and time, (spacetime) are not physical. You have already agreed to that.

15 minutes ago, 34student said:

 But nonphysical entities do not cause anything physical to happen.

And yet it has been observationaly verified that light follows the curves and warps of spacetime ( geodesics) and gravitational lensing. 

[34student]

17 minutes ago, swansont said:

A muon being shaped like a worldline is not “well known” and not a true statement.

 

Well then you do not understand fundamental implications of GR.  In GR particles extend through time.

 

[Markus Hanke]

16 hours ago, 34student said:

But because we saw that a frame of reference does not actually exist in any physical way or have any physical meaning and therefor is irrelevant to the physical mechanics of the universe, we are left with the question of what shape the Earth actually is.

When you say ‘actually is’ you are assuming the existence of some absolute reference frame - but no such thing exists. Shape is based on measurements of space, which are relational quantities, and thus require an observer to make sense. The best you can do is define ‘actually is’ as being the rest frame of the Earth, but that’s an arbitrary choice; there’s nothing special about that particular frame.

16 hours ago, 34student said:

Going back to my OP, how can we avoid some sort of superposition of position?

By using the appropriate formalism. In relativistic quantum mechanics, the wave function is always a representation of the Lorentz group - for bosons it will be a tensor of a rank equal to their spin; for spin-½ fermions, it will (in general) be a Dirac (bi)spinor. Both tensors and bispinors are covariant objects, meaning everyone agrees on them, and whether or not they describe a superposition of states is an invariant property. Thus, if there is no superposition in the rest frame, there is no superposition in any other frame too. The only thing observers disagree on is how far apart the particles are, but not whether there is a superposition; they’re just looking at the same system from a different angle in spacetime.

You continue to be stuck on the idea that there must be some absolute notion of space and time, some way things ‘really are’ in 3D. The highlighted part is the issue, because spacetime isn’t 3D, and it’s not Euclidean. If you use the appropriate 4D description instead, then there is no issue and no contradictions. Until you can mentally perform the 3D->4D paradigm shift, you will remain stuck on this.

[34student]

57 minutes ago, MigL said:

The 'duration' and 'length' of an event, in relativity, is equivalent to the projection on the spatial and temporal axis, of its rest frame ( proper ) length and duration.
This projection is different for different observers, depending on their position on the spatial/temporal axis. IOW, depending on the speed ( and vice versa ).

 

Yes, I am with you on this.  I understand.

57 minutes ago, MigL said:

 

The frame has no physical effect, nor does it change anything directly.
It is simply the point of view of the observer, taking his circumstances into consideration.
It is similar to measuring your shadow in a North facing frame, as opposed to a south facing frame. In the first you will measure your shadow to be very long because the sun is at your back, while in the second, you will be facing the sun , and will see little, or no shadow.

In your example, both universes are identical, they overlap perfectly.   

But when the universes of length contraction overlap, we do not get an exact match.  The positioning is different.  We have the same particles, but they are in different positions relative to themselves.

 

55 minutes ago, beecee said:

 Space and time, (spacetime) are not physical. You have already agreed to that.

I told you in my last post to you that I agreed that distance is not physical, not spacetime.  Spacetime is clearly physical.

[swansont]

29 minutes ago, 34student said:

We have the same particles, but they are in different positions relative to themselves.

That’s nonsensical. There is one particle, and “relative to itself” isn’t a thing. “Relative” requires two frames.

[studiot]

1 hour ago, 34student said:

We have the same particles, but they are in different positions relative to themselves.

This is a really clever trick, though I have never seen any conjuror perform it.

Here is a picture of particles in superposition.

[34student]

1 hour ago, swansont said:

That’s nonsensical. There is one particle, and “relative to itself” isn’t a thing. “Relative” requires two frames.

Particles should be in the same place that they are in.  If not, I do not know how else to describe it other than a superposition of position.

[swansont]

30 minutes ago, 34student said:

Particles should be in the same place that they are in.

They are. 

[34student]

1 minute ago, swansont said:

They are. 

Yet two different shapes of the same particles exist.

[swansont]

Just now, 34student said:

Yet two different shapes of the same particles exist.

True of any relative property. 

[pzkpfw]

18 minutes ago, 34student said:

Yet two different shapes of the same particles exist.

 

What observer will agree with this?

[MigL]

6 hours ago, 34student said:

We have the same particles, but they are in different positions relative to themselves.

I thought you said you understood relativity ...

Something cannot be relative to itself.
The particle has different positions ( and times ) relative to different observers.
Each observer, in a different frame, sees the particle in a different position ( and at a diferent time ).
That is why frames of reference are so important.