[horizon (OP)]

from http://uk.news.yahoo.com/38/20110415/ts ... fda55.html

Scientists make teleportation breakthrough
Friday, April 15 05:46 pm

Boffins from Japan and Australia have made a huge scientific breakthrough by successfully teleporting packets of light from one area to another.
The mind-bending project, led by Noriyuki Lee at the University of Tokyo, could lead to the creation of super-powerful quantum computers and revolutionise the telecommunications industry.

The team managed to teleport wave packets of light by destroying them in one place and re-creating them in another.

It's an incredible process that means transmitting large volumes of complex quantum information could be quicker than is currently possible.

The quantum physics term behind this experiment is 'entanglement'. It means that two particles can be bonded in such a way that even when separated by large distances, they are still linked. So what happens to one affects the other.

The team linked packets of light to half a pair of entangled particles. They destroyed one of the particles and the light itself, leaving just one remaining particle. This particle still contained detailed information about the light which they could then use to rebuild the original particle.

'Schrodinger's cat'

The process involves 'Schrodinger's cat'. Unfortunately it's not a real feline, but a hypothetical experiment first carried out in the 1935.

Schrödinger envisioned in a cat in a sealed box with a small amount of radioactive material and a Geiger counter measuring radiation. If the atom decayed the counter would release cyanide into the box and kill the cat.

According to quantum mechanics, the cat is neither dead nor alive. Until someone opens the box both possibilities exist. It's supposed to illustrate how in quantum mechanics particles can exist in suspended states of multiple possibilities.

The team at the University of Tokyo were able to put the light wave in a 'Schrödinger's cat' state with the help of a machine simply called 'The Teleporter', and make it have two opposite phases at the same time.

Professor Elanor Huntington, who was part of the research team, told ABC News: "What we've done is take a macroscopic beam of light and put it into a quantum superposition, which is extremely fragile, and teleported that from one place to another."

Doing this demonstrates that - for the first time - blocks of complex quantum information can now be carried by light.

"If we can do this, we can do just about any form of communication needed for any quantum technology," she said.

Unfortunately the breakthrough doesn't mean we'll ever be able to transport human beings, Star Trek style. At present even bacteria is far too complex to be transported.

Which leads to 2 questions to you all!
1) What do make of all this?
2) Can Quantum computers ever happen??

[Geezer]

Here's a working link.

http://uk.news.yahoo.com/38/20110415/tsc-scientists-make-teleportation-breakt-98fda55.html

I was under the impression that it's not possible to communicate information by this method, so if they can actually do that, it would be very interesting. Unfortunately, the article does not go into any detail about how they did it.


BTW, you'll find a discussion on this very subject here
http://www.thenakedscientists.com/forum/index.php?topic=38369.0;topicseen

[JP]

From what I've heard, there are three fundamental components of a quantum computer: data storage, data transfer and quantum gates (the things that do the computational operations).  In theory all of this can be built.  In practice, actually designing these components to work with a reasonable number of quantum bits is beyond us at the moment.  The big problem is that when a quantum bit interacts with it's surroundings, the information it contained gets entangled with those surroundings.  Since you can't easily measure the bit + its surroundings, nor can you pass the surroundings through a quantum gate, this information is essentially lost, and that quantum bit is rendered useless.  I would say that most research these days is about reducing the effect of decoherence.  Last I heard the biggest problem was storing information in between processing, since it's very hard to contain these particles for appreciable amounts of time without them decohering.

What this experiment seems to be claiming is that they've sent a lot of quantum information at once.    As far as quantum computing goes, I don't think this is immediately going to help, since the bottleneck is at data storage, not data transfer.  It could be useful once the data storage problem is overcome.

[Geezer]

I thought the article was referring to superluminal communication, but I probably got it wrong.

[JP]

Well, what they're doing is what commonly gets mistaken for superluminal communication.  As you mentioned, you can't send information this way without doing classical communication alongside it.  The usefulness of this isn't in superluminal communication, but in sending quantum states between locations, presumably for computing or encryption.