Quantum gravity, closer to TOE?

@humy said
He, just like I, never doubted it for the speed of particles and objects traveled through space WITHOUT quantum tunneling, NOT necessarily for particles traveled through space via quantum tunneling, which may or may not have been viewed by him (along with many but not all modern physicists) as a possible special albeit trivial exception to that. Even if he believed that wasn't a ...[text shortened]... /implied once he was wrong and I assert and always have asserted he was much smarter than you and I.

Since you claim you have no opinion on it then you do not disagree with me. Nothing important to discuss here.

@metal-brain said
Since you claim you have no opinion on it then you do not disagree with me.

I disagree with your claim that I arrogantly disagree with Einstein. I clearly didn't disagree with any of his opinions, at least not any that I am aware of. Your claim is clearly false. Nothing more to discuss here.

@humy said
I disagree with your claim that I arrogantly disagree with Einstein. I clearly didn't disagree with any of his opinions, at least not any that I am aware of. Your claim is clearly false. Nothing more to discuss here.

So you don't disagree with Einstein. What are you left with then?
Nothing more to discuss here.

@sonhouse said
@AThousandYoung
Could QT somehow be related to a particle leaving our dimension and going into another dimension and then back to our world?

No.

@metal-brain said
Nothing travels faster than light. Do you think you are smarter than Einstein? You don't make sense.

Point a laser at the moon and then sweep the beam so that the point of illumination on the surface of the moon goes from one pole to the other. It is a simple matter to make the illuminated point move faster than the speed of light.

The special theory of relativity has two physical axioms, one is the relativity axiom - that the laws of physics are the same in all frames of reference. The second axiom is that observers will all measure the speed of light to be the same. So if you are stationary on the earth and I am moving to the sun at half the speed of light I get the same number as you for the speed that light from the sun is moving towards us. The consequence of that is that the amount of energy needed to move physical modes past the speed of light is infinite.

I took a look at one of the references. What he seems to be saying is that the tunneling modes are virtual modes and so not on mass shell. He also seems to be saying that the total time measured for the particle to leave the emitter, get through the barrier and hit the target is greater than distance divided by speed of light in all frames of reference. It's only during tunneling through the barrier, when the tunneling particle is unobservable, that the particle goes faster than light. So overall relativity is being respected.

I'd have to read and think about the paper. I'm not sure if I believe him and need to have a think about what he's trying to say. I think that this is liable to have the same status as the EPR paradox.

https://arxiv.org/pdf/1003.3944.pdf

@deepthought said
It's only during tunneling through the barrier, when the tunneling particle is unobservable, that the particle goes faster than light. So overall relativity is being respected.

What many albeit not all modern physicists claim, rightly or wrongly (and I have no personal opinion on this), is that quantum tunneling involves something going over c. It is a controversial and contentious claim but, regardless of whether that claim is correct, one thing they are generally NOT saying is that this claim being true would CONTRADICT relativity. I don't know what Einstein's opinion was on that (I tried and failed to find out) but, whatever it was, he obviously didn't think it contradicts relativity either. Just like many laws of physics, there may be exceptions or loopholes in the c-speed-limit law and, where there is such an exception, that wouldn't prove the law 'wrong' but rather merely mean you would have to be careful to state those exceptions in the description of what the law says. Even if there are exceptions to the law and even if quantum tunneling involves such an exception, at best they are all trivial exception and don't prove either Einstein or relativity wrong. Unfortunately, I have noticed from many posts (and not just from here) that there are many layperson that don't understand this point and erroneously think it WOULD or even DOES prove Einstein and relativity wrong! Often I find it impossible to reason with such people to put them right; they just will not accept there can be an exception to a law and that law STILL being perfectly valid, and yet there are numerous examples of just such laws. What is the big deal of there being an exception to a law?

@deepthought said
Point a laser at the moon and then sweep the beam so that the point of illumination on the surface of the moon goes from one pole to the other. It is a simple matter to make the illuminated point move faster than the speed of light.

The special theory of relativity has two physical axioms, one is the relativity axiom - that the laws of physics are the same in all fram ...[text shortened]... at this is liable to have the same status as the EPR paradox.

https://arxiv.org/pdf/1003.3944.pdf

"So overall relativity is being respected."

If that is true why does the title of the article say otherwise? I didn't have time to read much of it, but I find it hard to believe.

@humy said
What many albeit not all modern physicists claim, rightly or wrongly (and I have no personal opinion on this), is that quantum tunneling involves something going over c. It is a controversial and contentious claim but, regardless of whether that claim is correct, one thing they are generally NOT saying is that this claim being true would CONTRADICT relativity. I don't know what ...[text shortened]... are numerous examples of just such laws. What is the big deal of there being an exception to a law?

Well, if there are exceptions then it's not a universal law.

@metal-brain said
"So overall relativity is being respected."

If that is true why does the title of the article say otherwise? I didn't have time to read much of it, but I find it hard to believe.

If a particle is observed at position x1 at time t1 and then at position x2 at t2 then the observer will conclude that its velocity is:

v = (x2 - x1)/(t2 - t1).

Suppose v > c, the speed of light. This means that the two events happen with a space-like separation. Because the separation is space-like the order of events can be different for different observers. In other words the second measurement happens before the first one for this observer. This does some damage to our notions of causality.

The paper claims that primitive causality is preserved. In section VIII the guy talks about measurements taking a finite amount of time, and that the apparent violation of causality in theoretical models is due to the authors failing to consider that observations take a finite amount of time.

@deepthought said
Well, if there are exceptions then it's not a universal law.

Whether it is a 'universal' law would depend on whether the supposedly full description of the law is stated in such a way as to take fully into account the exceptions.
If the supposed full description of the law is stated as nothing more than simply "X is always true" and there is an exception Y where it isn't then, obviously, its not universal. But we can always then remedy that by modifying the supposed full description of the law so its stated as "X is always true when Y doesn't apply" (or words of that effect) and then it may be universal. I believe that can be and should be done to the full description of the c-speed-limit law if or when we are really sure it really has an exception Y.

@deepthought said
If a particle is observed at position x1 at time t1 and then at position x2 at t2 then the observer will conclude that its velocity is:

v = (x2 - x1)/(t2 - t1).

Suppose v > c, the speed of light. This means that the two events happen with a space-like separation. Because the separation is space-like the order of events can be different for different observers. In ...[text shortened]... cal models is due to the authors failing to consider that observations take a finite amount of time.

It is because it is dependent on the observer that I am skeptical. The uncertainty principal is also variable when observed, but that is the trajectory. If speed is also variable when observed is the variability real?

Didn't Einstein say that god does not play dice or something like that? Then the reply was don't tell god what to do? If it is observer dependent I tend to think it is not real. In other words, if observing will change the result stop wasting your time observing it. It is an illusion.

@metal-brain said
It is because it is dependent on the observer that I am skeptical. The uncertainty principal is also variable when observed, but that is the trajectory. If speed is also variable when observed is the variability real?

Didn't Einstein say that god does not play dice or something like that? Then the reply was don't tell god what to do? If it is observer dependent I tend ...[text shortened]... r words, if observing will change the result stop wasting your time observing it. It is an illusion.

I'm not sure what you're getting at here. I'll reply to the part of your post I can reply to. Momentum/position uncertainty does not involve a fixed magnitude momentum varying in direction, the magnitude of the momentum is also uncertain. For massless particles the speed is always 1 (i.e. the speed of light in natural units), nevertheless the momentum is non-zero and subject to the uncertainty relation.

The observer has a central role in modern physics. The laws of physics are expected to be universal, in the sense that no observer should see phenomena that disagree with the laws. However, if there is an effect that depends on the absence of an observer then it is outside physics. In classical physics it was assumed that measurements could be done to arbitrary precision and that the distinction between ontology and epistemology was a game for philosophers. The theories of Special Relativity and Quantum Mechanics changed that.

@deepthought said
I'm not sure what you're getting at here. I'll reply to the part of your post I can reply to. Momentum/position uncertainty does not involve a fixed magnitude momentum varying in direction, the magnitude of the momentum is also uncertain. For massless particles the speed is always 1 (i.e. the speed of light in natural units), nevertheless the momentum is non-zero and s ...[text shortened]... was a game for philosophers. The theories of Special Relativity and Quantum Mechanics changed that.

"However, if there is an effect that depends on the absence of an observer then it is outside physics."

How do you know it is not the other way around? If an effect depends on an observer then perhaps that is outside physics. Observing changes the result, right?

@metal-brain said
"However, if there is an effect that depends on the absence of an observer then it is outside physics."

How do you know it is not the other way around? If an effect depends on an observer then perhaps that is outside physics. Observing changes the result, right?

I think you misunderstand what he is claiming here. His statement in its context was:

"The observer has a central role in modern physics. The laws of physics are expected to be universal, in the sense that no observer should see phenomena that disagree with the laws. However, if there is an effect that DEPENDS on the ABSENCE of an observer then it is outside physics. " (with my emphasis in capitals)

And in THAT above context he wouldn't necessarily be referring to whether the "Observing changes the result" (or anything like that) but rather he may be only referring to the fact that if there is an effect that DEPENDS on the ABSENCE of an observer then it is outside the STUDY of physics because that would mean that effect cannot be observed. I hope you understand that, in science, if something cannot be observed, not even 'observed' or detected ('detected' is probably the better word for it) highly indirectly via other observations and using extremely complex/subtle deduction/induction/extrapolation/Occam's-razor etc etc, then its not part of real science. True science can only deal with what can be knowable via observation (even if highly indirectly and via much application of logic and even a few necessary assumption).

@DeepThought
A simple answer but.....
Is there any theory that says what is happening?