Am I right that it is possible to send signals to the past with quantum entangled communication? I've heard, that on grounds of theory of relativity faster than light communication means that time communication is possible.
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Speaking to the past
Sat, 2009-12-12 18:48
#1
remade
Speaking to the past
Sat, 2009-12-12 19:02
#2
knasser
Re: Speaking with the past
Page 242, right hand column definitely states that Quantum Entanglement communications are (albeit expensive) not bound by the speed of light. I.e. you can have a real time conversation between people on Mars and the Kuiper Belt which would have a seven hour lag if you did it by radio, for example.
However, what does this mean in practical terms. Are you actually talking into the past? Are you not both just out of sync with each other? Does it matter if 12:00 on Mars talks to 18:00 on Pluto? They have no reference point by which they can take advantage of this, do they?
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Sat, 2009-12-12 19:13
#3
remade
Re: Speaking with the past
If you have faster than light communicators, certain bodies A and B, and send signal A -> B -> A, then you may get this signal at A from B before you even sent it to B from A.
Tue, 2009-12-15 06:52
#4
Zophiel
Re: Speaking with the past
My admittedly limited understanding of modern QE experiments is that the paired reactions take effect instantly. I'm sure this is a less than perfect analogy but think of each entangled pair as a single thing, not two. Its like a coin, if heads is facing the sender, tails is facing the receiver. Changing one necessarily changes both because they're not two discrete objects. The fact that this is true across (theoretically) infinite distance really irked Einstein.
Fri, 2010-01-15 20:10
#5
Arenamontanus
Re: Speaking to the past
Any kind of "instantaneous" communication causes trouble with special relativity. If A sends a message to B, in another reference frame (i.e. seen from a ship moving past at high speed) it clearly looks like B received the message before A sent it.
My standard gaming solution [*] to this is to invoke the Novikov self-consistency principle: trans-time communication cannot lead to paradoxes, because the probability of such states is zero (they interfere with themselves). That still won't solve the simultaneity issues, but for most practical situations these are minor. Transhumanity haven't got that many near-lightspeed ships.
[*] I'm rather proud of having a gaming group that forces me as a GM to make judgements on things like this. It is always better to decide before the campaign starts on whether functionalism, the many worlds interpretation or energy conservation is true in the setting. Just in case.
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