Slashdot Mirror
Laser Beam Teleported
Michael Wardle writes "ABC Australia reports that a team of scientists from the Australian National University have successfully teleported a laser beam. It seems that teleportation of solid bodies is still a way off, but at least we're a little closer to Slashdot's favorite super power." Another Australian newspaper has a more detailed story.
Because when we're talking about a beam of light, the notion of analyzing it, transmitting the information, and reproducing the original seems more like television than teleportation.
Like most of the non-hoax science stories on Slashdot that relate to fantastic-sounding possibilities (teleportation, time travel, etc.), this is most likely a breakthrough of some sort but not nearly as cool as the summary makes it sound.
Getting to the subject of destroying an object and creating an exact duplicate, it's a hazy issue. I understand how I'd theoretically be the same person if you were to reproduce me at the most detailed level, but I'm still nervous about potential problems with it.
For example, should the destruction of the original me fail, there are suddenly two of me in the Universe, each with a full claim to being me and each slightly different (based on the brief experiences that occur after the duplication). One interesting exploration of this scenario was featured in James Patrick Kelly's story, "Think Like a Dinosaur".
Well, if the person created was the exact same down to the quantum level, it would be you, exactly. Your last memory would be a strange tingling as your body was torn apart at the quantum level to be stored, then once you were recreated your memories would begin again. Now this raises all sorts of philosophical questions, like what happened to your soul when you were torn apart, but really, I dont believe in any of that mumbo-jumbo :P If it was proven to be safe i'd use it, sure.
Yeah I thought that was pretty funny too. I think the reporter is wrong, though -- the spooky part is that it happens *faster* than the speed of light. I'm pretty sure about this, in fact, because there's a famous Einstein line about "spooky action at a distance" referring to faster-than-light quantum effects, which I'm pretty sure the scientists quoted would be aware of.
That being the case, everyone here is totally missing the point. And in fact, the reporters who wrote the linked-to story missed it to, despite this quote:
The bits about teleporting solid objects (including humans) were just humoring the reporter -- sort of like the whole "could this experiment destroy the universe" thing surrounding supercolliders. The true interesting practical application of this is FTL communication -- vital for any space missions going much further than, say, Mars -- and pretty handy even if you're only that far away.
The "spooky action at a distance" is a weird consequense of the heisenberg uncertainity principle. It 'appears' to be an interaction, but in fact it's just the result of the coherency between two 'entangled' wavefunctions.
the 'yes' part is that to receive a teleportation, you have to have one of the entagled particles, and a measured quantity.
the 'no' part is that since the measured quantity is transmitted classicaly, there's no FTL transfer of anything.
-Kz-
The blueprint analogy shows a lack of understanding of entanglement. There is no blueprint at the receiving end, and no measurement and communication of instructions to replicate the properties of the sending photon. What happens is a seemingly spontaneous change in the properties of the receiving photon.
Whether this is teleportation or replication is more of a philosophical question, or maybe a matter of semantics. Is an object (or a laser beam) equal to the sum of its properties? If you can make the sum total of an object's quantum properties disappear from one place and reappear in another place, have you merely copied the object or have you moved it?
I think you've moved it, but questions like these deserve more than offhanded answers.
Right.. except the original beam no longer exists.. it's state has been frozen in something, and re-emitted later.
As for the difference... no science we have yet teleports actual particles.
It does bring up an interesting dilemma though...
if we COULD make a precise, quantum copy of a person, which one would be the 'real' person? Both would percieve they are real, both would be for ALL purposes, identical. If one were destroyed immediately after quantum duplication, there would be no way to find out which is the original.
So if someone duplicates you.. which one is really you? what happens to your sense of continuity?
I'm still considering very fast traveling of the light. If there was an impediment between the 1 meter, I'd consider teleportation.
There's a relativly (pun intended) interesting experiment on NEC Institute's web page. It proves that light can go faster than C. Here for NEC Faster than C webpage
It seems that this beam of light traveled about 3C. However, there's conjecture that it traveled slower, but time dilation made it seem 3C. That's unprovable at the time though.
The article says:
Using a process known as quantum entanglement, the researchers, led by 34-year-old physicist Ping Koy Lam, have disassembled a laser at one end of an optical communications system and recreated a replica a metre away
and
But the radio signal survives and is sent electronically to a receiving station, where within a nanosecond an exact replica of the beam - with the radio signal intact - is retrieved and decoded.
I'm having trouble working out whether that nano-second is the elapsed time from when the original beam is destroyed and the new one is created, or whether it's the amount of time required to recreate the beam from the received radio signal.
If it's the former then we're talking faster-than-light teleportation here because it takes light 3 nanoseconds to travel a yard.
It would be even better if it didn't have propagation time but hell, I'll settle for the speed at which a laser normally travels through a fiberoptic cable. That wouldn't disappoint me at all.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"