Does quantum entanglement allow information to travel faster than light?

[byron178]

Have you tried looking up more info elsewhere? I'm sure a simple google or wikipedia search would yield plenty of info.

i read the wiki article and it says quantum entanglement and time travel backwards have something in common.

 

[Drakkith]

Try looking for "Interpretations of Quantum Mechanics". That should have plenty of info on the different theories.

 

[byron178]

Try looking for "Interpretations of Quantum Mechanics". That should have plenty of info on the different theories.

is there a theory in which time travel backwards does not happen?

 

[Drakkith]

is there a theory in which time travel backwards does not happen?

I'm going to assume you didn't look anything up before you asked this again, as you posted 4 minutes after I did.
I don't know enough about QM to answer your question, but I am trying to help you. At least make an attempt to help yourself.

 

[byron178]

I'm going to assume you didn't look anything up before you asked this again, as you posted 4 minutes after I did.
I don't know enough about QM to answer your question, but I am trying to help you. At least make an attempt to help yourself.

no i did look it up,are you talking about the copenhagen interpretation?

 

[pawprint]

Does quantum entanglement allow information to travel faster than light?

The majority answer at this stage seems to be that information CAN travel instantaneously. I believe SciAm had a major article on this some 2 years ago saying that it had been demonstrated at desktop distances. Perhaps someone who has an on-line subscription with them could hunt this up?

I see no relevance here at all to time travel. A 'massless' photon carries momentum and is therefore limited to c, but transfer of 'pure' information apparently requires neither mass NOR momentum. If the majority answer here is true (as described in the previous paragraph) then information is neither mass nor energy, but something else entirely. F-MA=0.

 

[byron178]

The majority answer at this stage seems to be that information CAN travel instantaneously. I believe SciAm had a major article on this some 2 years ago saying that it had been demonstrated at desktop distances. Perhaps someone who has an on-line subscription with them could hunt this up?

I see no relevance here at all to time travel. A 'massless' photon carries momentum and is therefore limited to c, but transfer of 'pure' information apparently requires neither mass NOR momentum. If the majority answer here is true (as described in the previous paragraph) then information is neither mass nor energy, but something else entirely. F-MA=0.

so your saying that quantum entanglement does not involve time travel backwards?

 

[Drakkith]

I think the answer is that "We don't know whether entanglement involves time travel or not". Hence the different interpretations.

 

[SpectraCat]

Does quantum entanglement allow information to travel faster than light? http://en.wikipedia.org/wiki/Faster-than-light if you scroll down to quantum mechanics.

To go back to your initial question, the answer is "No. Information is not transmitted FTL by the collapse of entangled states."

It is true that if you perform a measurement on a member of an entangled pair, then you can immediately *infer* something about the other member, even if it is separated from you by a space-like interval. However although that "information" pertains to something happening in another light-cone, it originated with *your* measurement, and progates in space-time within *your* light-cone.

Some people are tempted to ask how the entangled partners "know when to collapse", when they are separated by a space-like interval, and one of the partners is measured. Nobody knows the answer to that question yet, and it may be that we are not even asking it in the correct way. Once upon a time I heard an explanation by Curt Wittig from USC that the collapse of the entangled state doesn't propagate through space-time, and thus is not bound by relativistic constraints. I confess that the details of his explanation were beyond me at the time .. I will try to find his papers on the subject and see if I understand them better now.

 

[Goldstone1]

anyone...?

Try the Transactional interpretation. It involves your time queeries.

 

[Goldstone1]

so your saying that quantum entanglement does not involve time travel backwards?

I'd say that there is still the possibillty.

 

[byron178]

The nature of the observation and the result.

were you talking about the transactional interpretation?

 

[byron178]

The majority answer at this stage seems to be that information CAN travel instantaneously. I believe SciAm had a major article on this some 2 years ago saying that it had been demonstrated at desktop distances. Perhaps someone who has an on-line subscription with them could hunt this up?

I see no relevance here at all to time travel. A 'massless' photon carries momentum and is therefore limited to c, but transfer of 'pure' information apparently requires neither mass NOR momentum. If the majority answer here is true (as described in the previous paragraph) then information is neither mass nor energy, but something else entirely. F-MA=0.

I do,Relativity says if something were to travel faster than light it will travel backwards in time in one frame of reference.

 

[UChr]

I do,Relativity says if something were to travel faster than light it will travel backwards in time in one frame of reference.

My understanding is that A is observed before B is observed (- so it is observed as 'travel backwards in time').
Whether A happened before B - according to coordinated clocks - requires enough information to reconstruct the situations - as with astronomical events.

 

[byron178]

My understanding is that A is observed before B is observed (- so it is observed as 'travel backwards in time').
Whether A happened before B - according to coordinated clocks - requires enough information to reconstruct the situations - as with astronomical events.

so this happens with quantum entanglement?

 

[SpectraCat]

so this happens with quantum entanglement?

What makes you think so?

 

[UChr]

As I see it: A deaf and a blind, observing lightning.
The blind observe lightning A before B (with ears) and the deaf observe B before A (with eyes) - without it is a real contradiction.

 

[DrChinese]

I do,Relativity says if something were to travel faster than light it will travel backwards in time in one frame of reference.

Relativity has nothing to do with it, and that is not what special relativity says anyway.

The effect occurs if you are in the same frame of reference. Ordering makes no difference in any frame of reference. What is called backward in time is simply a function of what you define as the cause and the effect. Essentially it is interpretational.

 

[byron178]

Relativity has nothing to do with it, and that is not what special relativity says anyway.

The effect occurs if you are in the same frame of reference. Ordering makes no difference in any frame of reference. What is called backward in time is simply a function of what you define as the cause and the effect. Essentially it is interpretational.

so entanglement has nothing to do with faster than light travel,communication,or time travel backwards?

 

[byron178]

As I see it: A deaf and a blind, observing lightning.
The blind observe lightning A before B (with ears) and the deaf observe B before A (with eyes) - without it is a real contradiction.

so entanglement has nothing to do with time travel backwards?

 

[DrChinese]

so entanglement has nothing to do with faster than light travel,communication,or time travel backwards?

Entanglement does not produce any effects which require relativistic consideration in the manner you describe. In addition, it *appears* as if the future and the past together form a context for an observation. Likewise, although influences propagate at a maximum of c, the net effect of an overall context can *appear* as if something happens FTL or even backwards in time. None of the experiments that demonstrate this involve any new physics, it is application of existing physics.

You can label those statements any way you like. We are getting into the semantics area, which is not a productive one as far as I am concerned. I hate to see time wasted debating definitions.

 

[byron178]

Entanglement does not produce any effects which require relativistic consideration in the manner you describe. In addition, it *appears* as if the future and the past together form a context for an observation. Likewise, although influences propagate at a maximum of c, the net effect of an overall context can *appear* as if something happens FTL or even backwards in time. None of the experiments that demonstrate this involve any new physics, it is application of existing physics.

You can label those statements any way you like. We are getting into the semantics area, which is not a productive one as far as I am concerned. I hate to see time wasted debating definitions.

so your saying nothing travel backwards in time with entanglement?

 

[DrChinese]

so your saying nothing travel backwards in time with entanglement?

In any quantum interaction, the past and the future form a context which will follow the Heisenberg Uncertainty Principle. Entanglement is simply a special case of this principle, in which does have a weird appearance because the context is more complex. I probably would not use the words "backwards in time" as I think that is somewhat misleading, and I think most people around here would agree.

 

[DevilsAvocado]

I do,Relativity says if something were to travel faster than light it will travel backwards in time in one frame of reference.

I agree with DrChinese.

However, the "FTL backward in time" stuff is true, but it looks like you have misinterpreted the details on Wikipedia about quantum entanglement:

"Certain phenomena in quantum mechanics, such as quantum entanglement, appear to transmit information faster than light. According to the no-communication theorem these phenomena do not allow true communication;"​

I.e. it looks like quantum entanglement transmits information faster than light... maybe you think it could be possible, in some way...?

Nevertheless, this is just dead wrong. Forget the word information, and remember the word correlation instead. There is no way in h*ll to utilize quantum entanglement for sending any information in any direction, all you get is random noise, thus – NO faster than light communication is possible.

I’ll give you an example:

Imagine Alice & Bob decides to make a lot of money by utilizing quantum entanglement to transmit information faster than light between the Tokyo Stock Exchange and the New York Stock Exchange. When the share price changes in Tokyo, they’ll send a coded message faster than light to New York, and are able to act on NYSE before anyone else.

First problem; even if they use photons they will of course travel at the speed of light. Therefore, they have to entangle 'a set' of photons in advance, and send them to New York for the "magic trick".

Now, Alice in Tokyo sees big changes on the market and she wants to send the message "EPR" to Bob, to signal a big buy of stocks in the Einstein-Podolsky-Rosen Company. Binary "EPR" translates to:

1000101 1000101 1010010

And Alice does everything in her power to enforce this binary sequence when she is measuring the photons 'pointing' up (1) and down (0).

Bob is real nervous and excited when he sees that a new "FTL message" has arrived from Tokyo! The message he receives looks like this:

1010010 1001110 1000100

And it translates to "RND"...?? Bob now thinks he’s instructed to buy stocks in the Random Company, and he completes the order from Alice...

Alice & Bob are now, due to the 'experiment', completely bankrupt and have stopped their 'quantum stock activities', for good.

Nevertheless, Alice & Bob wanted to find out what went wrong, and got together in New York to compare their binary sequences.

Bob..: 1010010 1001110 1000100 = RND
Alice: 0101101 0110001 0111011 = -1;

What the heck...?

Alice had failed completely in transmitting "EPR". She 'transmitted' something completely random, but the weird thing is that Bob got an inverted (XOR) version of Alice random noise – when Alice = 0, Bob = 1 and the other way around!? THEY ARE CORRELATED!​

This is quantum entanglement.

But there’s more to it than this. For example there is no way for Bob to know when Alice makes her measurement – except than signaling at (maximum) the speed of light that it is completed.

Same thing with establishing the correlations – they must meet in person, or communicate at (maximum) the speed of light, to see this 'pattern'. All they see one by one is random noise without any meaning whatsoever.

Same thing with Alice trying to enforce a determined result ("EPR") from a QM 50/50 measurement – this is just not possible according to the Heisenberg uncertainty principle.

The 'perfect correlations' [1/0, 0/1] in this example is the version from EPR 1935, but in 1964 John Bell showed that there’s more 'subtle' correlations between Alice & Bob in http://en.wikipedia.org/wiki/Bell%27s_inequality" , which finally proved that Local Realism is a dead parrot (some say it just smells funny, but I smell a rat ).

Hope it helps.

 

[byron178]

I agree with DrChinese.

However, the "FTL backward in time" stuff is true, but it looks like you have misinterpreted the details on Wikipedia about quantum entanglement:

"Certain phenomena in quantum mechanics, such as quantum entanglement, appear to transmit information faster than light. According to the no-communication theorem these phenomena do not allow true communication;"​

I.e. it looks like quantum entanglement transmits information faster than light... maybe you think it could be possible, in some way...?

Nevertheless, this is just dead wrong. Forget the word information, and remember the word correlation instead. There is no way in h*ll to utilize quantum entanglement for sending any information in any direction, all you get is random noise, thus – NO faster than light communication is possible.

I’ll give you an example:

Imagine Alice & Bob decides to make a lot of money by utilizing quantum entanglement to transmit information faster than light between the Tokyo Stock Exchange and the New York Stock Exchange. When the share price changes in Tokyo, they’ll send a coded message faster than light to New York, and are able to act on NYSE before anyone else.

First problem; even if they use photons they will of course travel at the speed of light. Therefore, they have to entangle 'a set' of photons in advance, and send them to New York for the "magic trick".

Now, Alice in Tokyo sees big changes on the market and she wants to send the message "EPR" to Bob, to signal a big buy of stocks in the Einstein-Podolsky-Rosen Company. Binary "EPR" translates to:

1000101 1000101 1010010

And Alice does everything in her power to enforce this binary sequence when she is measuring the photons 'pointing' up (1) and down (0).

Bob is real nervous and excited when he sees that a new "FTL message" has arrived from Tokyo! The message he receives looks like this:

1010010 1001110 1000100

And it translates to "RND"...?? Bob now thinks he’s instructed to buy stocks in the Random Company, and he completes the order from Alice...

Alice & Bob are now, due to the 'experiment', completely bankrupt and have stopped their 'quantum stock activities', for good.

Nevertheless, Alice & Bob wanted to find out what went wrong, and got together in New York to compare their binary sequences.

Bob..: 1010010 1001110 1000100 = RND
Alice: 0101101 0110001 0111011 = -1;

What the heck...?

Alice had failed completely in transmitting "EPR". She 'transmitted' something completely random, but the weird thing is that Bob got an inverted (XOR) version of Alice random noise – when Alice = 0, Bob = 1 and the other way around!? THEY ARE CORRELATED!​

This is quantum entanglement.

But there’s more to it than this. For example there is no way for Bob to know when Alice makes her measurement – except than signaling at (maximum) the speed of light that it is completed.

Same thing with establishing the correlations – they must meet in person, or communicate at (maximum) the speed of light, to see this 'pattern'. All they see one by one is random noise without any meaning whatsoever.

Same thing with Alice trying to enforce a determined result ("EPR") from a QM 50/50 measurement – this is just not possible according to the Heisenberg uncertainty principle.

The 'perfect correlations' [1/0, 0/1] in this example is the version from EPR 1935, but in 1964 John Bell showed that there’s more 'subtle' correlations between Alice & Bob in http://en.wikipedia.org/wiki/Bell%27s_inequality" , which finally proved that Local Realism is a dead parrot (some say it just smells funny, but I smell a rat ).

Hope it helps.

so your saying when faster than light happens it will travel backwards in time and this happens with entanglement? i ask because alice receives the message -1.but doesn't something have to travel backwards in time since something is happening faster than light?

 

[DevilsAvocado]

It looks like you and I are entangled, because all that comes out is random noise...

Where did I say that "faster than light happens"...??

NO, KEIN, AUCUNE, NINGUNO, НИКАКОЙ, NULLUM, NÃO faster than light communication is ever never possible!

The thing you’re fishing for "travel backwards in time", is more than a dead parrot (if you ask me), because then you will have to violate http://en.wikipedia.org/wiki/Causality_(physics)" , i.e. you travel back in time and kill your grandfather before he meets the your grandmother, and then you will never exist, thus you couldn’t do the time travel in the first place, so on and so forth.

The ONLY thing traveling in quantum entanglement is the photons at the speed of light. They are 'interconnected', in sharing the same http://en.wikipedia.org/wiki/Wave_function" . No one has ever seen the wavefunction. In current science – it’s just a 'virtual' mathematical tool.

But let’s pretend that the wavefunction does exist, like a 'rubber band' that gets stretched between two 'balls' (photons). Now, if you cut a rubber band in half – would you say it has "traveled" in any direction??

 

[Duplex]

so your saying when faster than light happens it will travel backwards in time and this happens with entanglement? i ask because alice receives the message -1.but doesn't something have to travel backwards in time since something is happening faster than light?

If you still hold out for traveling backwards in time after all the qualified answers in this thread, I am afraid you at least have to wait for a Kaluza-Klein type of a curled extra time dimension to be discovered in the future and brought into mainstream science.

No, I'm not saying that time travel backwards is possible in the future.
The only thing we know about the future physics is the possibility to discuss it in PF - in the future.

 

[Drakkith]

so your saying when faster than light happens it will travel backwards in time and this happens with entanglement? i ask because alice receives the message -1.but doesn't something have to travel backwards in time since something is happening faster than light?

Ok, let me try to explain this. IF it turns out that entangled particles communicate instantly and are able to tell each other what to do even after one has alrady been detected, then yes, it would be "time travel" in the sense that particle A gets detected BEFORE particle B, yet the path that B takes determines what A can do after it is already detected.

However it is NOT proven beyond reasonable doubt that this is what's happening. And even if it is, we have no way of sending signals between two people at a greater speed than c. Please, there is NO way to say either way at this point, so there is no reason to continually ask whether or not time travel is happening. Your better off forgetting about the whole matter in my opinion.

 

[Breakout Hit]

Are you sure about this? I thought that once you altered the state of one particle the two were no longer entangled. For example, if two electrons are generated and each must have opposite spins, then if you measure them you will find that they always do. But if you do something so that one of the particles gets their spin flipped, then the entanglement is broken. After the interaction both electrons could be spin up or spin down depending on what you did.

Pretty sure they both change, its what Einstein called "spooky action at a distance." Believe it peeved him because it implied travel of something at faster than the speed of light. I could be wrong but that's how I remember it...

 

[Drakkith]

Pretty sure they both change, its what Einstein called "spooky action at a distance." Believe it peeved him because it implied travel of something at faster than the speed of light. I could be wrong but that's how I remember it...

If so, I haven't seen anything that implies that yet. The only thing that comes close to my limited knowledge is some experiments where they measured the averages of different properties of entangled particles, where the probabilities of each should have been equal. It turned out that measuring two particular properties were different than two other properties even though they should have been about the same. I can't remember exactly which is why I say I haven't seen anything yet.

 

[byron178]

Ok, let me try to explain this. IF it turns out that entangled particles communicate instantly and are able to tell each other what to do even after one has alrady been detected, then yes, it would be "time travel" in the sense that particle A gets detected BEFORE particle B, yet the path that B takes determines what A can do after it is already detected.

However it is NOT proven beyond reasonable doubt that this is what's happening. And even if it is, we have no way of sending signals between two people at a greater speed than c. Please, there is NO way to say either way at this point, so there is no reason to continually ask whether or not time travel is happening. Your better off forgetting about the whole matter in my opinion.

is it time travel backwards?

 

[Drakkith]

is it time travel backwards?

What do you think?

 

[DevilsAvocado]

* sigh *

backward contemplating

 

[byron178]

What do you think?

no i do not.

 

[Drakkith]

no i do not.

Could you elaborate a bit? What exactly are you saying?