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For the first time in the history of quantum mechanics, scientists have been able to transmit a black and white image without having to send any physical particles. The phenomenon can be explained using the Zeno effect, the same effect that explains that movement itself is impossible.
The journal article is in Proceedings of the National Academy of Sciences of the United States of America (DOI: 10.1073/pnas.1614560114)
Wikipedia has an article about the quantum Zeno effect.
Related stories:
Physicists Break Distance Record for Quantum Teleportation
First Covert Communication System with Lasers
Long-Range Secure Quantum Communication System Developed
China's "Quantum-Enabled Satellite" Launches
How to Outwit Noise in Quantum Communication
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Direct Counterfactual Quantum Communication Claimed
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The last time I saw him he was walking down Lover's Lane holding his own hand.
-- Fred Allen
(Score: 2) by JoeMerchant on Saturday May 20 2017, @11:29PM (3 children)
So, I just want to draw this one out, on phosphor screen as it were:
Assuming that "spooky action at a distance" happens "instantaneously" (whatever that means), I'm going to define 0:00 as "now" for two frames, A and B which are located 1 light hour apart, stationary with respect to each other.
At 1:00, the light from A at 0:00 is reaching B, and the light from B at 0:00 is reaching A. If spooky action at a distance could carry information, it could carry that light picture from A to B and B could see what A looks like at 0:00 right away at 0:00. No amount of bouncing back and forth will ever get any information about what A looks like at 1:00 back to A before 1:00. Draw in C and D, make it a 3D system, same thing applies, information about A at 1:00 will not reach anywhere before 1:00.
If you want to include relativistic motion, B could be orbiting a black hole at close proximity and be experiencing 50% time dilation. Light from A at 0:00 now reaches B at B's concept of 0:30 local time, but C - located just to the side of the black hole and not experiencing significant time dilation receives that A 0:00 light at C 1:00 perceived time. Just because B is only up to 0:30 local time doesn't give anyone "access to the future" - it just means that B is aging more slowly. A 1:00 information could be "spooky transmitted" to B, and in B's frame of reference it's only 0:30, but when B transmits that information back to A, it's still going to be A 1:00 + transmission delays, the spooky information transfer doesn't reach back in time. Or does it? This is all made up, anyway, no accepted theories believe in "spooky transmission of information," so, maybe we entangle some particles, split them up, put some in B and they "age" at half rate, then when A does spooky transmission, it reaches B at the "age matched" time - but, wait, B 1:00 is A 2:00, so, again, A can't get information about A 1:00 that way until A 2:00. Try it in reverse, now B's 1:00 information is pushed out to "time matched" A at 1:00, woo hoo, you've put information into the past because at A 1:00 B is only at 0:30, bounce that around a contrived chain and then pop the information across a conventional light speed communication channel and you've got information about the future of B back in B, but this is only assuming that the "instant communication" particles are affected by time dilation and then "instantly communicate" backwards and forwards in the instant time frame... seems doubly contrived.
Just think like Hollywood: time travel just works, now write a story around it and the consequences, don't get hung up in the details - be like Mary Shelly: "reverse the poles, minus to plus, plus to minus - Eeeeeeeeeeeeee its Aliiiiiiiiiiiive!"
🌻🌻 [google.com]
(Score: 2) by wonkey_monkey on Sunday May 21 2017, @10:37AM (2 children)
Sticking close to a black hole to keep your clock running slow is general relativity, not special relativity, and is not symmetrical (A sees B run slow, B sees A run fast).
If there is just simple relative motion, then it's as I described (A sees B run slow, B sees A run slow). The line of "now" from A intersects B at a certain point in B's time, but B's line of "now" from that point in time has a different angle to A's, and so intersects A at an earlier time (if distance is increasing; if decreasing, repeated messages end up in the future).
systemd is Roko's Basilisk
(Score: 2) by JoeMerchant on Sunday May 21 2017, @12:08PM (1 child)
The "simple relative motion" example always tossed around on pop-sci shows is: A is A "stationary". B accelerates away from A to relativistic speed, now B runs slow. B keeps on going in a loop at relativistic speeds (lots of acceleration there), then returns to A - the "interstellar traveler" from "B ship" has aged 1 year, but his family and friends on A have all been dead for a thousand. What I've never seen the pop-sci shows get into is "C ship" that tears off in the opposite direction of B, now C is moving even closer to the speed of light, relative to B, but if they both arrive back at A simultaneously, A is aged the same for both of them, but why are they the same age as each other?
I still love the concept that the photons leaving the surface of stars 10 billion years ago are arriving in our telescopes "instantly," unaged since they were emitted.
🌻🌻 [google.com]
(Score: 2) by wonkey_monkey on Sunday May 21 2017, @06:11PM
B and the C are the same age because they've undergone identical accelerations. The one who ages the most is the one who took the straightest path from launch to meet-up - in this case A, because he didn't accelerate at all, he just let "meet-up" come to him. The other two took wiggly paths, but identically wiggly, so the amount of time experienced by themselves on their trip is the same.
During the constant relative motion parts (among all three of them), they all see the others' clocks runs slow. But during accelerations towards each other, there are times when others' clocks run fast.
Kind of... but the standard physicist answer to this is that photons don't have reference frames, so you can't consider anything from their "point of view" - they don't have one. The math does pretty clearly point in that direction, though.
systemd is Roko's Basilisk