Entanglement and time travel

[Guest TargetX]

Two particles can become "entangled" with each other at a quantum level and when they are separate there is some link between the two, I have read.

 

well if one of these particles is travels "at" the speed of light for a year and then returns two where its partner is the two particles should be entangle through time as well as via their proximity.

 

could this property be used to send information backward and forward through time?

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[swansont]

Two particles can become "entangled" with each other at a quantum level and when they are separate there is some link between the two' date=' I have read.

 

well if one of these particles is travels "at" the speed of light for a year and then returns two where its partner is the two particles should be entangle through time as well as via their proximity.

 

could this property be used to send information backward and forward through time?

_________________[/quote']

 

 

Forward? Yes, just like any other means of transmitting information (speed-wise) Backward? No.

 

<Obi-Wan>Use the search function, Luke.</Obi-Wan>

[Spyman]

could this property be used to send information backward and forward through time?

AFAIK They have not yet even succeded in sending information FTL.

 

Information in a letter may be moving Faster Than Light but You can't read it until the letter arrives.

 

To send information backwards in time You need to send one of the entangled particles backwards.

(If it's possible and without destroying the entanglement.)

 

Your setup only ends up with one particle older than the other, both are still in the same time frame.

(If it's possible to store one of the entangled particles.)

 

I don't know the creditability for this link, but it's interesting: Quantum Entanglement and Causality

In relativity the idea of instantaneity itself is relative; if two spacelike-separated events are simultaneous in some frame of reference, there will always be other frames of reference where one precedes the other, and still other frames of reference the perceived order is reversed. So from some point of view, the event which is supposed to be doing the influencing doesn’t happen until after the event which is being influenced.

This is obviously a strange conclusion; however, it is not necessarily wrong. Clearly for certain kinds of backwards causality, paradoxical situations can arise. For instance, I might send a message back to my past self saying ‘Do not under any circumstances send this message,’ if superluminal (faster than light) signalling were allowed and relativity correct. If I heed the warning, I will never send the message; how then can I come to receive it?

Notably, none of the possibilities for utilising quantum entanglement makes explicit use of its supposed superluminal character. Whether it is physically possible to make any use of this remains to be seen, but most commentators agree it is unlikely.

http://fergusmurray.members.beeb.net/Causality.html

[Severian]

If you could send information faster than the speed of light by using entanglement, then you would be able to send a message into the past too. But since you can't send it faster than the speed of light, you can't send it backwards in time either.