Relativity?

How does science work? And what's all this about quantum mechanics?

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davidm
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Re: Relativity?

Post by davidm »

Viveka wrote: Tue Nov 07, 2017 7:47 pm
davidm wrote: Tue Nov 07, 2017 7:46 pm
Viveka wrote: Tue Nov 07, 2017 7:35 pm

If we could somehow build quantum entangled cameras and tvs. :) Doesn't matter because it's a thought experiment, the same method Einstein used!
Quantum entangled cameras would NOT broadcast instantaneous feeds!
And why is that? Quantum Entanglement is a method of faster-than-light travel of information.
No it is not!!! :o
Viveka
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Re: Relativity?

Post by Viveka »

davidm wrote: Tue Nov 07, 2017 7:49 pm
Viveka wrote: Tue Nov 07, 2017 7:47 pm
davidm wrote: Tue Nov 07, 2017 7:46 pm

Quantum entangled cameras would NOT broadcast instantaneous feeds!
And why is that? Quantum Entanglement is a method of faster-than-light travel of information.
No it is not!!! :o
It is. You're being willfully ignorant right now.
davidm
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Re: Relativity?

Post by davidm »

Viveka wrote: Tue Nov 07, 2017 8:31 pm
davidm wrote: Tue Nov 07, 2017 7:49 pm
Viveka wrote: Tue Nov 07, 2017 7:47 pm

And why is that? Quantum Entanglement is a method of faster-than-light travel of information.
No it is not!!! :o
It is. You're being willfully ignorant right now.
OMFG :|

You have NO IDEA what you are talking about -- as usual!
davidm
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Re: Relativity?

Post by davidm »

Quantum influence at a superluminal distance is NOT communication of information at a superluminal distance!
OuterLimits
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Re: Relativity?

Post by OuterLimits »

Viveka wrote: Tue Nov 07, 2017 8:31 pm
davidm wrote: Tue Nov 07, 2017 7:49 pm
Viveka wrote: Tue Nov 07, 2017 7:47 pm

And why is that? Quantum Entanglement is a method of faster-than-light travel of information.
No it is not!!! :o
It is. You're being willfully ignorant right now.
quantum entanglement looks like a space-like faster-than-light something or other but that something is not "information". There is no unambiguous way to say which direction the something-or-other traveled. Was it caused the the one event or the other? We'll never need to know because light-speed limits on anything you would call information is not violated.
Viveka
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Re: Relativity?

Post by Viveka »

davidm wrote: Tue Nov 07, 2017 8:33 pm
Viveka wrote: Tue Nov 07, 2017 8:31 pm
davidm wrote: Tue Nov 07, 2017 7:49 pm

No it is not!!! :o
It is. You're being willfully ignorant right now.
OMFG :|

You have NO IDEA what you are talking about -- as usual!
I'm not going to argue what neither of us understand if I'm wrong.

Also,

https://science.nasa.gov/science-news/s ... _entangled
davidm
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Re: Relativity?

Post by davidm »

Viveka wrote: Tue Nov 07, 2017 8:42 pm
davidm wrote: Tue Nov 07, 2017 8:33 pm
Viveka wrote: Tue Nov 07, 2017 8:31 pm

It is. You're being willfully ignorant right now.
OMFG :|

You have NO IDEA what you are talking about -- as usual!
I'm not going to argue what neither of us understand if I'm wrong.

Also,

https://science.nasa.gov/science-news/s ... _entangled
Yeah, and so?

How does the above allow anyone to communicate -- to transfer information -- faster than light?

Before wading off into another morass, did you READ my recent post on how breaking inertial frames resolves your so-called "twin's contradiction"? Yes or no?
davidm
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Re: Relativity?

Post by davidm »

OuterLimits wrote: Tue Nov 07, 2017 8:39 pm
Viveka wrote: Tue Nov 07, 2017 8:31 pm
davidm wrote: Tue Nov 07, 2017 7:49 pm

No it is not!!! :o
It is. You're being willfully ignorant right now.
quantum entanglement looks like a space-like faster-than-light something or other but that something is not "information". There is no unambiguous way to say which direction the something-or-other traveled. Was it caused the the one event or the other? We'll never need to know because light-speed limits on anything you would call information is not violated.
Right.
davidm
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Re: Relativity?

Post by davidm »

We can easily set up a classical equivalent of quantum entanglement.

I buy a deck of playing cards and throw away all but two: the ace of spades and the ace of hearts.

I seal each card in an envelope.

I give one envelope to Bob and another to Alice.

I inform them that one envelope holds the ace of spades and the other the ace of hearts, but neither knows the contents of the envelope. All they do know is that on classical probability, the odds of finding one or the other card, when they open their envelopes, are 50/50.

Bob takes his sealed envelope to California and Alice to New York. Light travels very fast. If light circumnavigated the earth, it would do so about seven and a half times every second. But that is still a finite rate of speed. Hence it follows that it would take light some finite rate of speed, however ridiculously tiny, to travel from New York to California.

In California, Bob opens his envelope. He discovers that he has the ace of spades.

He therefore knows instantly that Alice, in New York, has the ace of hearts in her envelope. (Actually, he doesn’t really know this instantly — he knows it in the almost but not quite inconceivably tiny amount of time it takes for light to reflect off the card and register in his brain. But this is still less time than it takes for light — i.e., information — to travel from Alice in New York to Bob in California, or vice versa.)

But — crucially — even though Bob learned the state of Alice’s card in New York faster than it takes light to travel from New York to California, he did not learn the state of Alice’s card faster than the speed of light — he had to wait for the light to bounce off his own card and register in his own brain to learn the state of Alice’s card by learning the state of his own card. It’s just that light he needed to learn the state of his own card (and hence Alice’s card) took less time to travel from his card to his brain, than it takes light to travel from New York to California.

Query: Has Bob learned anything in classical entanglement faster than the speed of light?

And if the answer is no, would the answer be different in the case of quantum entanglement?
OuterLimits
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Re: Relativity?

Post by OuterLimits »

davidm wrote: Tue Nov 07, 2017 10:16 pm We can easily set up a classical equivalent of quantum entanglement.

I buy a deck of playing cards and throw away all but two: the ace of spades and the ace of hearts.

I seal each card in an envelope.

I give one envelope to Bob and another to Alice.

I inform them that one envelope holds the ace of spades and the other the ace of hearts, but neither knows the contents of the envelope. All they do know is that on classical probability, the odds of finding one or the other card, when they open their envelopes, are 50/50.

Bob takes his sealed envelope to California and Alice to New York. Light travels very fast. If light circumnavigated the earth, it would do so about seven and a half times every second. But that is still a finite rate of speed. Hence it follows that it would take light some finite rate of speed, however ridiculously tiny, to travel from New York to California.

In California, Bob opens his envelope. He discovers that he has the ace of spades.

He therefore knows instantly that Alice, in New York, has the ace of hearts in her envelope. (Actually, he doesn’t really know this instantly — he knows it in the almost but not quite inconceivably tiny amount of time it takes for light to reflect off the card and register in his brain. But this is still less time than it takes for light — i.e., information — to travel from Alice in New York to Bob in California, or vice versa.)

But — crucially — even though Bob learned the state of Alice’s card in New York faster than it takes light to travel from New York to California, he did not learn the state of Alice’s card faster than the speed of light — he had to wait for the light to bounce off his own card and register in his own brain to learn the state of Alice’s card by learning the state of his own card. It’s just that light he needed to learn the state of his own card (and hence Alice’s card) took less time to travel from his card to his brain, than it takes light to travel from New York to California.

Query: Has Bob learned anything in classical entanglement faster than the speed of light?

And if the answer is no, would the answer be different in the case of quantum entanglement?
Bell's inequality suggests that this simple classical type of entanglement is insufficient to describe what is seen using physically distant quantum measurements.
davidm
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Re: Relativity?

Post by davidm »

OuterLimits wrote: Tue Nov 07, 2017 10:41 pm
davidm wrote: Tue Nov 07, 2017 10:16 pm We can easily set up a classical equivalent of quantum entanglement.

I buy a deck of playing cards and throw away all but two: the ace of spades and the ace of hearts.

I seal each card in an envelope.

I give one envelope to Bob and another to Alice.

I inform them that one envelope holds the ace of spades and the other the ace of hearts, but neither knows the contents of the envelope. All they do know is that on classical probability, the odds of finding one or the other card, when they open their envelopes, are 50/50.

Bob takes his sealed envelope to California and Alice to New York. Light travels very fast. If light circumnavigated the earth, it would do so about seven and a half times every second. But that is still a finite rate of speed. Hence it follows that it would take light some finite rate of speed, however ridiculously tiny, to travel from New York to California.

In California, Bob opens his envelope. He discovers that he has the ace of spades.

He therefore knows instantly that Alice, in New York, has the ace of hearts in her envelope. (Actually, he doesn’t really know this instantly — he knows it in the almost but not quite inconceivably tiny amount of time it takes for light to reflect off the card and register in his brain. But this is still less time than it takes for light — i.e., information — to travel from Alice in New York to Bob in California, or vice versa.)

But — crucially — even though Bob learned the state of Alice’s card in New York faster than it takes light to travel from New York to California, he did not learn the state of Alice’s card faster than the speed of light — he had to wait for the light to bounce off his own card and register in his own brain to learn the state of Alice’s card by learning the state of his own card. It’s just that light he needed to learn the state of his own card (and hence Alice’s card) took less time to travel from his card to his brain, than it takes light to travel from New York to California.

Query: Has Bob learned anything in classical entanglement faster than the speed of light?

And if the answer is no, would the answer be different in the case of quantum entanglement?
Bell's inequality suggests that this simple classical type of entanglement is insufficient to describe what is seen using physically distant quantum measurements.
Right! They're different!

BUT the relevant question is, does this difference mean that information can be communicated at superluminal velocities in the case of quantum entanglement?

It should also be noted that "spooky action at a distance" (along with wavefunction collapse and indeterminism) simply does not occur on the parsimonious Many Worlds interpretation of QM.
davidm
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Re: Relativity?

Post by davidm »

I'm not suggesting that classical entanglement is the same as, or a proper analogy to, quantum entanglement. My point is that just as information or communication cannot transcend light speed in classical entanglement, so too it will not do so in quantum entanglement.
davidm
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Re: Relativity?

Post by davidm »

In the case of quantum entanglement, continuing with the card analogy, we would say there that is no definite content of the sealed envelope — no prior, but unknown, state of the cards. Until the envelope or envelopes are opened, the spades/hearts are in superposition. When someone, either Bob or Alice, opens his or her envelope, the wavefunction collapses and instantaneously “causes” the card in the other envelope, even if that card is on the other side of the observable universe, to take on the opposite value.

This is very weird. But can this phenomenon be exploited to facilitate superluminal communication, or information transfer?

And the answer is no, for the same reason that such communication cannot be achieved in classical entanglement.
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Noax
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Re: Relativity?

Post by Noax »

Viveka wrote: Tue Nov 07, 2017 8:31 pm
davidm wrote: Tue Nov 07, 2017 7:49 pm
Viveka wrote: Tue Nov 07, 2017 7:47 pmQuantum Entanglement is a method of faster-than-light travel of information.
No it is not!!! :o
It is. You're being willfully ignorant right now.
It is not. No message can be thus sent, and QM does not assert any faster-than-light causation.
davidm wrote: Tue Nov 07, 2017 11:12 pmWhen someone, either Bob or Alice, opens his or her envelope, the wavefunction collapses and instantaneously “causes” the card in the other envelope, even if that card is on the other side of the observable universe, to take on the opposite value.
QM does not say this and you know that there is no "instantaneous" relation between events with wide spatial separation.
Your language expresses several philosophical choices of interpretation. QM just says what the observations will be. It does not interpret those observations as either causing the other.
davidm
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Re: Relativity?

Post by davidm »

Noax wrote: Wed Nov 08, 2017 12:50 am
Viveka wrote: Tue Nov 07, 2017 8:31 pm
davidm wrote: Tue Nov 07, 2017 7:49 pm
No it is not!!! :o
It is. You're being willfully ignorant right now.
It is not. No message can be thus sent, and QM does not assert any faster-than-light causation.
davidm wrote: Tue Nov 07, 2017 11:12 pmWhen someone, either Bob or Alice, opens his or her envelope, the wavefunction collapses and instantaneously “causes” the card in the other envelope, even if that card is on the other side of the observable universe, to take on the opposite value.
QM does not say this and you know that there is no "instantaneous" relation between events with wide spatial separation.
Your language expresses several philosophical choices of interpretation. QM just says what the observations will be. It does not interpret those observations as either causing the other.
I agree. That is why I put the word "causes" in quote marks.

Personally I think, though can't prove, that the Many Worlds interpretation of QM is the correct interpretation, in which case spooky action at a distance, indeterminism and the mysterious wave function collapse do not occur.
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