Observers

[exchemist]

Indeed, and then went on to explain that you could take the seesaw away altogether, but the "correlation" between two entangled particles would remain the same. If one goes "up" (or reverses spin), the other necessarily goes "down" (or reverses spin) at the same time. They remain "correlated".

Those few paragraph confirmed and increased my layman's intuitive understanding of the fundamental arguments about entanglement.

As did this simple illustration;
I could argue that your post makes no sense, because you spelled the word "seesaw" incorrectly.
Do you see what I mean? Doesn't add much to understanding each other does it?
btw. English is my second language.

Instead of generously accepting any inadvertent errors I made in presenting the abstract analogy, there was no effort to even try and understand this layman's playful "thought experiment".

All I received was immediate rejection and dismissal, except for Karenmansker, who made an effort to understand and actually "saw" what I was trying to convey.

That's nonsense. Several people, including The God, pointed out quite patiently, over several posts, why your seesaw analogy does not work.

And then you chose to claim it was good by reference to a link written someone you described as a "real scientist" but who is not identified, writes on a website devoted to a fictional work by a notoriously bad and exploitative writer, about an unrecognised fringe activity called "noetic science", and makes metaphysical claims that are quite unjustified by any science. Some "real scientist".

 

[danshawen]

Stop pontificating.
You have no way of knowing that entanglement violates SR.

For a very, very good reason--you can't set up an experiment that confirms information is communicated when you measure entangled states. You can't postulate a thought experiment either (it would be placed under arrest by the thought police).

But, measurements of entangled photons give random results. How is a random result a communication? Is it like: "I might wire that money to you, or maybe I won't", or "If there are any tapes, I might let you know" . . . ?

By continuing to claim you know something nobody else does, you don't look very scientific, you look more like a crank: ("I alone understand the problem", etc).

Humor me for long enough to do just one more thought experiment.

Let's posit for a moment that relativity is entirely correct and that there is no means of getting a signal across 13 billion light years by any other means than by light propagating from point a to point b.

Now think about the idea that a beam of photons is already there (from point a to b), vastly separated. Think about the idea of a pair of entangled particles that are somehow stationary at either end. Each of the entangled particles "know" from which direction they arrived at point a or point b, respectively.

In this scenario, the particles simply 'stop', and turn about 180 degrees from the DIRECTION they were facing. Has any energy propagated to make this happen? If you observe that either the one at point a or point b has turned, you instantly know what happened to the other entangled twin. How long does it take for a different direction to be chosen with respect to the one from which a photon arrived, anywhere in a universe permeated by an inertialess quantum field that is not spinning? "Not spinning" or changing direction is a kind of inertia also.

If the quantum field in which the mechanism that produced the particles is sensitive to direction, AND if the entangled photons have traveled as they do in a straight line from one end of the universe to the other and are still entangled, then entanglement or 'disentanglement' is nothing more exotic than turning around (changing direction).

This somehow makes perfect sense to me. I don't understand why, but it does. Reducing 'real' simultanaeity to requiring only one observer and one event makes sense as well.

And it does look like something that, in a limited sense, could be made use of to build an extremely fast computational engine, which we know is your focus. I'm sorry that I can't provide any further clues as to how large a qubit might be, but this looks like something more analogous to conventional computing, but at much "higher" / "lower" speeds of computation locally.

It seems to function more like an accumulator (the computational 'action' register) than a deep memory device, so no doubt the first ones will need to interface to more conventional deep memory, if only to keep pairs of entangled qubits straight. The conventional memories will need to keep track of at least three states; entangled 'up', entangled 'down', and 'not entangled'. Worse, this memory transfer interface can't possibly happen without losing information, unless it is 'cloned' somehow.

In the strictest sense, this is the domain of engineering, not science. It has an element of inspiration.

I never had any tapes; just a useless idea about a change of direction being the basis of quantum entanglement.

 

[iceaura]

Those few paragraph confirmed and increased my layman's intuitive understanding of the fundamental arguments about entanglement.

If they confirmed you in your allegiance to the seesaw confusion, that's not so good.

Well, a layman has to start somewhere, no?

The two ends of a physical seesaw are not entangled. Not at all. Not even metaphorically. Don't start there.

All I received was immediate rejection and dismissal, except for Karenmansker, who made an effort to understand and actually "saw" what I was trying to convey.

Karenmansker praised and reinforced you in what appears to be a fundamental misconception - that separate objects connected by physical forces and chains of cause and effect are entangled.
I, on the other hand, did a bit of casual arithmetic and answered all three of your original questions as posed. Then I gave you a clearer "seesaw" model to think about, avoiding the misleading intuition of physical joinery. Was I offending you somehow?

 

[origin]

Now think about the idea that a beam of photons is already there (from point a to b), vastly separated. Think about the idea of a pair of entangled particles that are somehow stationary at either end. Each of the entangled particles "know" from which direction they arrived at point a or point b, respectively.

This scenario seems crazy. What do you mean the particles know which direction they came from?

If you observe that either the one at point a or point b has turned, you instantly know what happened to the other entangled twin.

Huh? It sounds like you think that if one entangled photon were to change direction due to a gravity well that the other photon would also change direction instantly. Is that something you think can happen with entangled particles?

 

[Write4U]

If they confirmed you in your allegiance to the seesaw confusion, that's not so good.

I merely pointed out that a misstatement does not necessarily invalidate the message.

The two ends of a physical seesaw are not entangled. Not at all. Not even metaphorically. Don't start there.
Karenmansker praised and reinforced you in what appears to be a fundamental misconception - that separate objects connected by physical forces and chains of cause and effect are entangled.

I did not see it that way. I believe Km's post merely recognized my inadequate attempt to illustrate the concept of correlation between two somehow connected (entangled) objects, such as playfully narrated in the metaphor of the quantum seesaw in a quantum playground in the first link.

I, on the other hand, did a bit of casual arithmetic and answered all three of your original questions as posed. Then I gave you a clearer "seesaw" model to think about, avoiding the misleading intuition of physical joinery. Was I offending you somehow?

Of course not, you were (in effect) correcting my misleadingly inadequate physical example. I tried to qualify it as an abstract metaphor, but that was obviously not persuasive, as apparently was the analogy from the first link I provided.

At least I can say that I am not the only who has used that playful quantum seesaw metaphor, which TG properly identified as intended for laymen to get a basic "feel" of the concept of entanglement.

Note that in the second part of the first link, the "narrator" did removed the quantum seesaw from the analogy and introduced the concept of "persistent correlation", which to me was a new expression in context of entanglement.

What about the second link and the illustration of Bob and Alice receiving the entangled but unequal masses (m1 and m2) and whoever receives m1 instantly knows that the other has or will receive m2 (and vice versa)?
While still inadequately simple (as explained in the narrative), I immediately understood the concept of persistent correlation between m1 and m2 in context as a form of entanglement.

IMO, another small step in gaining deeper understanding of the fundamental concept of entanglement.

As I have said before, I am not here to argue QM or GR, but to gain some fundamental understanding of the concepts. I am here to learn, but often the discussion is much too complex (citing names and theories I have never even heard of) for me to intuit and I am much to old to attend college and invest years of study in a formal setting. This is why I am here as my best opportunity to ask a question on a complicated subject.

I am always grateful when someone takes time to explain some fundamental aspect of physics, especially when it is so counter intuitive that even he greatest minds have problems with it and resort to expressions like "spooky action at a distance".

 

[hansda]

However long it takes for the speed of sound for that material to travel 1000 miles, I believe.

Will it not violate the basic physics principle of "conservation of angular momentum"?

 

[The God]

Will it not violate the basic physics principle of "conservation of angular momentum"?

Interesting point.
The very possibility of violation of Conservation of angular momentum for a planetary system or binary system, called for infinite speed of gravity in Newtonian Gravitational theory.

In case of seesaw, there is no such violation. I do not see that.

 

[origin]

Will it not violate the basic physics principle of "conservation of angular momentum"?

No. Why do you think it would?

 

[hansda]

Interesting point.

Good. You find this interesting.

The very possibility of violation of Conservation of angular momentum for a planetary system or binary system, called for infinite speed of gravity in Newtonian Gravitational theory.

What is "speed of gravity"? You mean conservation of angular momentum is violated in Newtonian Model?

In case of seesaw, there is no such violation. I do not see that.

One side of a lever goes down; other side of the lever- no movement. Is it not violation of the conservation of angular momentum?

 

[hansda]

No. Why do you think it would?

See post #309, last sentence.

 

[The God]

Good. You find this interesting.



What is "speed of gravity"? You mean conservation of angular momentum is violated in Newtonian Model?



One side of a lever goes down; other side of the lever- no movement. Is it not violation of the conservation of angular momentum?

Imagine your seesaw in vertical plane instead of horizontal. Now disturb it a bit and it will start in an angular motion that means it will have angular momentum. Original angular momentum =0, is it not a violation? If not why?

 

[origin]

One side of a lever goes down; other side of the lever- no movement. Is it not violation of the conservation of angular momentum?

It does go up, read what I wrote. It would not happen instantly since that would not be possible and would violate known physics.

 

[karenmansker]

It does go up, read what I wrote. It would not happen instantly since that would not be possible and would violate known physics.

So . . . . . are you (Origin) saying that (perhaps) quantum entanglement also does NOT happen instantaneously . . . and is NOT possible and would violate known physics? . . . or are you saying the example given cannot be described as an 'entangled' system . . . . because the information transfer is not instantaneous? Thanks for your clarification and for providing some factual references.

As a related 'aside' . . . . if information transfer is instantaneous in a 'true' quantum entangled system, how does that instantaneous action propagate over such immense (perhaps infinite?) distances (proposed by some) and how does it do so in essentially "zero" time. "Because the system is entangled" . . . . is NOT a scientifically-viable answer unless the issue of 'entanglement transfer mechanisms' can be demonstrated. IMO, if instantaneous information transfer happens in zero time, one must necessarily appeal to unknown (to current physics) mechanisms . . . perhaps . . . . even . . . non-physical?, metaphysical?, subquantum? etheral? (pun intended!) . . . . any/all very difficult to convincingly demonstrate, I might add . . . .

 

[danshawen]

This scenario seems crazy. What do you mean the particles know which direction they came from?


Huh? It sounds like you think that if one entangled photon were to change direction due to a gravity well that the other photon would also change direction instantly. Is that something you think can happen with entangled particles?

Yes. The direction is very important. Impossible without that element, in fact.

Mirrors work without changing entanglement because after reflection, a single direction is conserved.

If one of two entangled particles fell into the event horizon of a black hole, yes, it would no longer be entangled, but no, the experiments so far work just fine in low Earth orbit or on the surface.

 

[origin]

So . . . . . are you (Origin) saying that (perhaps) quantum entanglement also does NOT happen instantaneously . . . and is NOT possible and would violate known physics? . . . or are you saying the example given cannot be described as an 'entangled' system . . . . because the information transfer is not instantaneous? Thanks for your clarification and for providing some factual references.

The lever system is clearly not an example of quantum entanglement.

As a related 'aside' . . . . if information transfer is instantaneous in a 'true' quantum entangled system

Apparently information cannot be transfered instantaneously, however the state of the 2 particles can change instanteneously (or close to it).
I have no idea how this happens.

 

[danshawen]

The greatest scientist who ever lived termed entanglement "spooky". Crazy is a considerable upgrade from spooky.

There's a reason an all pervading quantum field isn't spinning, even a little bit, and except for that, what we term as "space" (light travel time) is inertialess.

That same quantum field can be flattened to zero distance by nothing more exotic than an appropriate reference frame in relative motion, 0.99999999... x c or so. So, is it really any wonder that quantum field can be made to behave as an infinitely rigid solid, in terms of changing spin directions?

 

[Write4U]

Imagine your seesaw in vertical plane instead of horizontal. Now disturb it a bit and it will start in an angular motion that means it will have angular momentum. Original angular momentum =0, is it not a violation? If not why?

I am not sure if I understand the analogy. A seesaw has a fulcrum, does your example of a vertical plane include a fulcrum?

I need to ask one more; does a perfectly centered fulcrum in a plane create a superposed state of the two sides always maintaining a net zero balance (correlation)?

 

[exchemist]

The lever system is clearly not an example of quantum entanglement.

Apparently information cannot be transfered instantaneously, however the state of the 2 particles can change instanteneously (or close to it).
I have no idea how this happens.

Surely it is not that the state changes, but that determination of one also instantly determines the other?

 

[exchemist]

Imagine your seesaw in vertical plane instead of horizontal. Now disturb it a bit and it will start in an angular motion that means it will have angular momentum. Original angular momentum =0, is it not a violation? If not why?

Because whatever it is that disturbs it acquires an equal and opposite angular momentum as it does so.

 

[danshawen]

Imagine your seesaw in vertical plane instead of horizontal. Now disturb it a bit and it will start in an angular motion that means it will have angular momentum. Original angular momentum =0, is it not a violation? If not why?

Because the force can be made instantaneous, and the original zero value of angular momentum does not change.