Relation of time and speed of light

[disarray]

ajb

 

You stated that "using quantum entanglement does not allow faster than light communication."

 

I am a layperson who is eager to discuss this topic with other lay people. I note that you are a professor of mathematics, so I am guessing that I may have misunderstood your statement. However, it is my understanding that the main reason that Einstein described entanglement as "spooky action at a distance" is that the information seemed to be converted almost instantaneously between particles (e.g., electrons), and certainly much much faster than the speed of light...thus the idea of entanglement seemed to go against both his theories as well as Newtons, and everybody elses for that matter.

 

I have just started researching this topic and one thing I noticed is that some experts claim that acceleration is necessary for time dilation to take place, and some say not. Apparently, though, Einstein did not restrict the effect to just situations where acceleration happened when he first outlined it in the Theory of Special Relativity. Also, the simplified explanations that I have read about it in terms of the Lorenz Transformation do not seem to require it.

 

Typical explanations use the example of a light beam that is going back and forth between two mirrors on a rocket ship....Because the rocket ship is moving, an observer on earth sees the light beam going in a zigzag fashion because it is going back and forth between two mirrors, say, horizontally to the earth observer, but also away from him. For the guy on the spaceship, the light is just going back and forth between the mirrors. The point is that the earth observer sees the light beam going further over a period of say, a second, than the guy on the spaceship, though the shorter distance that the light travels on the space ship is covering the space between the mirrors as fast as anything in the universe can go. The result is that, from the earth observers point of view, the light beam is going faster than the speed of light, but, in order for that to be possible, the light on the rocket ship must be in a time frame that is slower than that of earths time frame....and, since the space guy is on the same space ship as the mirrors, he too will be in that slowed down time frame. (There is also the related thing about space ship as well as the space between earth and, say, the nearest star to which the space ship is going, also being contracted.) Anyway, that's where I am at, at the moment, and I hope i got it reasonably right.

Edited June 14, 2016 by disarray

[StringJunky]

 

ajb

 

You stated that "using quantum entanglement does not allow faster than light communication."

The two states is like on the faces of a coin. If you know the state of the one you observe you know the other. Once you break the entanglement (collapse the wave function) by observing, there's no way to know, possibly change it and then restore the entanglement (restore the wave function)

Edited June 14, 2016 by StringJunky

[disarray]

String Junky said "If you know the state of the one you observe you know the other. Once you break the entanglement (collapse the wave function) by observing, there's no way to know, possibly change it and then restore the entanglement (restore the wave function)"

 

Yes, I have heard that objection before and it makes some sense. One article making this claim says that the information is not exchanged faster than the speed of light, but rather that "Alice’s measurement changes the universe in a way that gives Bob’s particle a definite property to measure that it did not previously possess."

 

But hey, to my mind that suggests that the information transaction is not only happening faster than the speed of light, but that it is done by reorganizing everything in the universe, much like, perhaps, the mousetrap/ping pong ball illustration of how a nuclear chain reaction takes place. Only instead of saying that there is a direct line between the first trap that goes off and the last, you say that it is more like filling an entire football field with traps and then saying that the last one to go off at the other end of the field goes off indirectly after virtually every other trap in the field goes off. https://www.sciencenews.org/blog/context/einstein-was-wrong-about-spooky-quantum-entanglement

 

In any case, I am wondering why scientists are routinely claiming that they have shown that entangled particles affect each other at specific distances:

"Einstein was so skeptical about quantum entanglement that he wrote a paper in 1935 titled “Can quantum-mechanical description of physical reality be considered complete?” He argued that it was not possible. In this, Einstein has been proven [to be] wrong. Researchers recently accessed entangled information over a distance of 15 miles."

 

http://unreasonable.is/quantum-computing-is-about-to-overturn-cybersecuritys-balance-of-power/

 

 

 

 

Edited June 14, 2016 by disarray

[swansont]

Ok, but the issue is, I could only provide the logical model, the formalism would require too long a learning curve on my part, though mostly it would only require logical states. If your still interested in seeing the model, I could spend some time cleaning up a more presentable synopsis, for the QM portion.

You could show in the current formalism how a "differential" hidden variable mattered. Or explain what that even means. Because the form of the hidden variable is not an issue with the Bell explanations with which I am familiar.

 

In any case, I am wondering why scientists are routinely claiming that they have shown that entangled particles affect each other at specific distances:

Do they make that claim? They have measured the entanglement, but AFAIK absent the claim that the particles have affected each other (though pop-sci articles may phrase it that way)

[Raider5678]

ajb

 

You stated that "using quantum entanglement does not allow faster than light communication."

 

I am a layperson who is eager to discuss this topic with other lay people. I note that you are a professor of mathematics, so I am guessing that I may have misunderstood your statement. However, it is my understanding that the main reason that Einstein described entanglement as "spooky action at a distance" is that the information seemed to be converted almost instantaneously between particles (e.g., electrons), and certainly much much faster than the speed of light...thus the idea of entanglement seemed to go against both his theories as well as Newtons, and everybody elses for that matter.

 

I have just started researching this topic and one thing I noticed is that some experts claim that acceleration is necessary for time dilation to take place, and some say not. Apparently, though, Einstein did not restrict the effect to just situations where acceleration happened when he first outlined it in the Theory of Special Relativity. Also, the simplified explanations that I have read about it in terms of the Lorenz Transformation do not seem to require it.

 

Typical explanations use the example of a light beam that is going back and forth between two mirrors on a rocket ship....Because the rocket ship is moving, an observer on earth sees the light beam going in a zigzag fashion because it is going back and forth between two mirrors, say, horizontally to the earth observer, but also away from him. For the guy on the spaceship, the light is just going back and forth between the mirrors. The point is that the earth observer sees the light beam going further over a period of say, a second, than the guy on the spaceship, though the shorter distance that the light travels on the space ship is covering the space between the mirrors as fast as anything in the universe can go. The result is that, from the earth observers point of view, the light beam is going faster than the speed of light, but, in order for that to be possible, the light on the rocket ship must be in a time frame that is slower than that of earths time frame....and, since the space guy is on the same space ship as the mirrors, he too will be in that slowed down time frame. (There is also the related thing about space ship as well as the space between earth and, say, the nearest star to which the space ship is going, also being contracted.) Anyway, that's where I am at, at the moment, and I hope i got it reasonably right.

Reasonably right, but not entirely so. The speed limit doesn't matter for point of view, only the distance covered in a given amount of time.

[ajb]

However, it is my understanding that the main reason that Einstein described entanglement as "spooky action at a distance" is that the information seemed to be converted almost instantaneously between particles (e.g., electrons), and certainly much much faster than the speed of light...thus the idea of entanglement seemed to go against both his theories as well as Newtons, and everybody elses for that matter.

The key point is that technically, you cannot send a message, and so information, faster than the speed of light using 'spooky action'. Nature has just the right amount of noise, i.e., the states that a particle takes are 'chosen' randomly, so that sending a message that way is impossible. There is no violation of causality as we know it.

[Delta1212]

"Spooky action at a distance" is only spooky in light of some other quantum mechanical things.

 

At face value, it would be no different to having one red card and one green card, dropping each in an envelop, handing each envelop to a person that doesn't know which is which and then sending them off to opposite ends of the Earth.

 

As soon as one of them opens their envelop, they instantly know the color of the card in the other envelop on the opposite side of the Earth, faster than the other person could transmit that information to them (or perhaps even before the other person has even checked their envelop). That's not spooky and you certainly wouldn't expect to be able to transmit any messages from one side of the Earth to the other using that method. You could have a preset message included in the envelop or something, but once the two carriers have separated and are at opposite locations, they can't transmit any information from one to the other through their envelops.

 

The reason that the "spooky action at a distance" thing comes in, is that we know through other means that in the quantum realm neither "card" is in a definite state of being green or red until someone opens their envelop and checks the color. That collapses the wave function for the color of the card and also instantly collapses the wave function of the other card, so that if you open your envelop and find a red card, your opposite will find a green card, no matter when they open their envelop in comparison to you.

 

If there is a 50/50 chance of your card turning out red, then if you opened your card, and your opposite opened their card after you, but before any signal traveling at the speed of light could reach from your position to theirs, the results will still be perfectly correlated.

 

You still can't send information from one to the other any more than you could in the classical scenario, but the wave function collapse allowed for the correlation to be maintained without information being sent from one quantum card to the other at subliminal speeds.

[swansont]

And, I will add, the Bell inequalities tell us that there is no secret way that the card really was red (or green) the whole time, because that's the point of those experiments. The results are inconsistent with there being a local hidden variable (and the form of this variable is not specified, which is why I don't see how the details of it can matter at all).

[Raider5678]

"Spooky action at a distance" is only spooky in light of some other quantum mechanical things.

At face value, it would be no different to having one red card and one green card, dropping each in an envelop, handing each envelop to a person that doesn't know which is which and then sending them off to opposite ends of the Earth.

As soon as one of them opens their envelop, they instantly know the color of the card in the other envelop on the opposite side of the Earth, faster than the other person could transmit that information to them (or perhaps even before the other person has even checked their envelop). That's not spooky and you certainly wouldn't expect to be able to transmit any messages from one side of the Earth to the other using that method. You could have a preset message included in the envelop or something, but once the two carriers have separated and are at opposite locations, they can't transmit any information from one to the other through their envelops.

The reason that the "spooky action at a distance" thing comes in, is that we know through other means that in the quantum realm neither "card" is in a definite state of being green or red until someone opens their envelop and checks the color. That collapses the wave function for the color of the card and also instantly collapses the wave function of the other card, so that if you open your envelop and find a red card, your opposite will find a green card, no matter when they open their envelop in comparison to you.

If there is a 50/50 chance of your card turning out red, then if you opened your card, and your opposite opened their card after you, but before any signal traveling at the speed of light could reach from your position to theirs, the results will still be perfectly correlated.

You still can't send information from one to the other any more than you could in the classical scenario, but the wave function collapse allowed for the correlation to be maintained without information being sent from one quantum card to the other at subliminal speeds.

Woah O.O

[disarray]

I think recent posts suggests that there is little actual evidence that information is transferred between entangled particles at a speed faster than light:

"The transfer of state between Photon A and Photon B takes place at a speed of at least 10,000 times the speed of light, possibly even instantaneously, regardless of distance.

A proposed experiment would send one photon of the entangled pair to the orbiting International Space Station, a distance of around 310 miles (500 kilometers). This would be the largest distance that has been experimentally tested." http://www.livescience.com/28550-how-quantum-entanglement-works-infographic.html

Of course, I don't think anyone has a very clear idea as to what such quantum information really is... perhaps we cant say that it is as much of an existing thing as a photon,(though other 'entities such as "force," "energy," "time," "gravity" and "space" are all pretty nebulous animals themselves as well). Indeed, Bohr famously remarked that "whoever thinks that they understand quantum theory...doesn't" and I think that he had such things as what Einstein called "spooky action at a distance" in mind when he said it.

Edited June 15, 2016 by disarray

[ajb]

Of course, I don't think anyone has a very clear idea as to what such quantum information really is...

Maybe, but people tend to have in mind Shannon's Information Theory when they talk about information. It is not that the particles do not 'talk to each other' in some way, but no information can be exchanged in that way.

[disarray]

ajb: Am not mathematically versed, so just try to find plausible metaphors. Was Shannon theory modified to fit quantum theory?. I gather that the issue of entropy may fit into all of this as well.

[ajb]

Was Shannon theory modified to fit quantum theory?

The notion of information is basically the 'surprise in a message' (i.e., the 'randomness' of the next symbol in your message).

 

For discrete systems (bits etc), you need quantum information theory. Here there is a natural generalisation of Shannon's notion of information known as the von Neumann entropy.

 

Still, the modern interpretation of causality is that no information can be exchanged at a rate faster than the speed of light. You cannot send messages using quantum entanglement.

Edited June 15, 2016 by ajb

[disarray]

Ajb:

So what do you think of the claim that, as I have mentioned in another thread, "because the total angular moment of the Universe must stay constant, you can then predict that if you measure one of these entangled particles and they have an up spin, then the other one in the pair must have a down spin - otherwise the laws of the Universe would be breached."

 

http://www.sciencealert.com/watch-this-is-how-quantum-entanglement-really-works

 

Hence the explanation that the process of "talking to each other," as you say, is virtually immediate even though, as you also say, no information is transferred.

 

Similarly, here is a quote from Lily Asquith, a physics postdoctoral student at Argonne National Laboratory in Chicago. She works on data from the Atlas particle detector at Cern's Large Hadron Collider, so I wouldn't dismiss the comment as New Age nonsense:

"Electrons interact via the electromagnetic field, aka the photon. All the electrons in the universe and all the photons in the universe are talking to each other all the time. They are all connected, no matter how far apart, by the electromagnetic field, which has infinite range**. They can be thought of as little clouds which have a dense foggy core and then misty edges, but that would be wrong because there are no edges. The mistiness goes on for ever, overlapping with every other misty cloud everywhere in the universe."

http://www.theguardian.com/profile/lily-asquith

Edited June 15, 2016 by disarray

[ajb]

Ajb:

So what do you think of the claim that, as I have mentioned in another thread, "because the total angular moment of the Universe must stay constant, you can then predict that if you measure one of these entangled particles and they have an up spin, then the other one in the pair must have a down spin - otherwise the laws of the Universe would be breached."

This is a statement of conservation of total angular momentum. It may not be true for the whole Universe, but for closed systems it is okay. So, we do indeed expect what you say, and this is what is seen.

[swansont]

 

 

Similarly, here is a quote from Lily Asquith, a physics postdoctoral student at Argonne National Laboratory in Chicago. She works on data from the Atlas particle detector at Cern's Large Hadron Collider, so I wouldn't dismiss the comment as New Age nonsense:

"Electrons interact via the electromagnetic field, aka the photon. All the electrons in the universe and all the photons in the universe are talking to each other all the time. They are all connected, no matter how far apart, by the electromagnetic field, which has infinite range**. They can be thought of as little clouds which have a dense foggy core and then misty edges, but that would be wrong because there are no edges. The mistiness goes on for ever, overlapping with every other misty cloud everywhere in the universe."

http://www.theguardian.com/profile/lily-asquith

 

 

 

 

But if you wiggle an electron, and electron 30 cm away won't know about that, or respond to the change, for a nanosecond.

[TakenItSeriously]

You could show in the current formalism how a "differential" hidden variable mattered. Or explain what that even means. Because the form of the hidden variable is not an issue with the Bell explanations with which I am familiar.

I've made no secret that I am not a physicist or mathematician, so formalism aside, I will try instead try to explain it logically.

 

In order to do this we must imagine a hypothetical differential universe that consists of dual realities that are equal and opposite and locked in entanglement.

 

Therefore, in the example with the EPR entanglement paradox, there actually exists two realities with two versions of Alice and two versions of Bob.

 

In the first reality:

Alice measures the X-spin with 100% certain results of + and Bob measures the Z-spin with non-determinate results 50:50 + or -

 

In the second reality:

Bob measures the X-Spin with 100% certain results of - and Alice measures the Z-spin with non-determinate results of 50:50 - or +

 

Therefore the information does not actually travel any distance and only travels between alternate realities which occupy the same space in alternate timelines.

Edited June 15, 2016 by TakenItSeriously

[Strange]

This sounds like the Many Worlds interpretation. Is that what you mean?

[TakenItSeriously]

This sounds like the Many Worlds interpretation. Is that what you mean?

In a sense, only instead of infinite realities, only two realities that are equal and opposites are needed.

 

Think of it like yin and yang, or a universe that allows for free will or chance between outcomes. Without a differential universe, duality doesn't exist and the only universe that could exist would be one that is completely deterministic where cause and effect will create a chain of events that can only end up with a single outcome till the end of time.

Edited June 15, 2016 by TakenItSeriously

[Strange]

In a sense, only instead of infinite realities, only two realities that are equal and opposites are needed.

 

But you need a pair of universes for every pair of entangled particles.

[swansont]

I've made no secret that I am not a physicist or mathematician, so formalism aside, I will try instead try to explain it logically.

 

In order to do this we must imagine a hypothetical differential universe that consists of dual realities that are equal and opposite and locked in entanglement.

 

Therefore, in the example with the EPR entanglement paradox, there actually exists two realities with two versions of Alice and two versions of Bob.

 

In the first reality:

Alice measures the X-spin with 100% certain results of + and Bob measures the Z-spin with non-determinate results 50:50 + or -

 

In the second reality:

Bob measures the X-Spin with 100% certain results of - and Alice measures the Z-spin with non-determinate results of 50:50 - or +

 

Therefore the information does not actually travel any distance and only travels between alternate realities which occupy the same space in alternate timelines.

 

 

That sounds a lot like the many-worlds interpretation of QM, which does not IMO solve the problem you think you are avoiding (you have to instantly create all of the states of everything in each universe. Same nonlocality problem.). But that discussion belongs in another thread.

[TakenItSeriously]

But you need a pair of universes for every pair of entangled particles.

Not really, all entangled particles create a single indeterminate universe till the point of observation defines the event.

 

Edit to add, if you think this is intriguing, the model is more than just a differential universe that completes QM. For instance all charged particles become dipoles across time, therefore gravity becomes a loop that stretches across world lines. So we now have a mechanistic explanation of a macro version of the quantum gravity loop that is required for linking QM to Relativity.

Edited June 15, 2016 by TakenItSeriously

[michel123456]

"Spooky action at a distance" is only spooky in light of some other quantum mechanical things.

 

At face value, it would be no different to having one red card and one green card, dropping each in an envelop, handing each envelop to a person that doesn't know which is which and then sending them off to opposite ends of the Earth.

 

As soon as one of them opens their envelop, they instantly know the color of the card in the other envelop on the opposite side of the Earth, faster than the other person could transmit that information to them (or perhaps even before the other person has even checked their envelop). That's not spooky and you certainly wouldn't expect to be able to transmit any messages from one side of the Earth to the other using that method. You could have a preset message included in the envelop or something, but once the two carriers have separated and are at opposite locations, they can't transmit any information from one to the other through their envelops.

 

The reason that the "spooky action at a distance" thing comes in, is that we know through other means that in the quantum realm neither "card" is in a definite state of being green or red until someone opens their envelop and checks the color. That collapses the wave function for the color of the card and also instantly collapses the wave function of the other card, so that if you open your envelop and find a red card, your opposite will find a green card, no matter when they open their envelop in comparison to you.

 

If there is a 50/50 chance of your card turning out red, then if you opened your card, and your opposite opened their card after you, but before any signal traveling at the speed of light could reach from your position to theirs, the results will still be perfectly correlated.

 

You still can't send information from one to the other any more than you could in the classical scenario, but the wave function collapse allowed for the correlation to be maintained without information being sent from one quantum card to the other at subliminal speeds.

Is that accurate? (the bold part in the above)

[Strange]

Is that accurate? (the bold part in the above)

 

As far as I can tell, yes.

[swansont]

Is that accurate? (the bold part in the above)

 

 

Yes.