Slashdot Mirror
The First Universal Quantum Network
MrSeb writes "German scientists at the Max Planck Institute of Quantum Optics have created the first 'universal quantum network' that could be feasibly scaled up to become a quantum internet. So far their quantum network only spans two labs spaced 21 meters apart, but the scientists stress that longer distances and multiple nodes are possible. The network's construction is ingenious: Each node is represented by a single rubidium atom, trapped inside a reflective optical cavity. These atoms communicate with each other by emitting a single photon over an optical fiber. Each atom is a quantum bit — a qubit — and the polarization of the photon emitted carries the quantum state of the qubit. The receiving qubit absorbs the photon and takes on the quantum state of the transmitter. Voila: A network of qubits that can send, receive, and store quantum information. In another, probably more exciting test, the emitted photons were actually used to entangle the rubidium atoms."
When stupid ACs stop posting lousy first posts.
I have no idea what any of that means! or what it's ultimate implications are technologically speaking but it sounds awesome!
Anyone care to enlighten me on the subject?
FTA: In theory, entangled qubits could be the basis of a quantum network with zero latency over any distance, which would make it rather useful for the intergalactic Galnet that will eventually succeed the internet. I'm pretty sure it's impossibly to transfer information faster than the speed of light http://en.wikipedia.org/wiki/No-communication_theorem
I'll be impressed when they figure out how to harness entangled particles to achieve instant transfer of information over vast distances.
Imagine a world with no RF generated, yet completely connected. Better yet... imagine the entire solar system or beyond connected with such a network.
I am no physicist, so I am actually asking seriously to those of you who are.
As it is already know, particles which are entangled at the quantum level have an instant and equal reaction on one another regardless of distance. Would it not be possible to use this "Quantum Internet" for C from say, a satellite controller a rover on Mars and one on Earth?
I have heard that it is not really workable, but is that from an engineering prospective or from a laws of physics perspective?
Doesn't the Heisenberg Uncertainty principle kind of say that when these machines are determining spins of particles, that they cause them to change? ie entropy?
So "Never", then?
bah.
From TFA, this is apparently a huge improvement on previous attempts, but it's still not exactly dazzling. What sort of self-correcting protocol do you need to handle 499 of every 500 bits being lost?
Virtually serving coffee
You can't copy quantum state. The only way it can carries the quantum state of something is if it also destroys that something's quantum state. (But of course you can't destroy quantum state either, you've effectively just swapping quantum state.)
So information might be passed around, but it's never actually being shared.
Which isn't much of a network.
Disclaimer - I'm rusty.
Also FatPhil on SoylentNews, id 863
Sounds like it's going to be a pretty gigantic leap to go from this experiment to an entire Internet. Keeping in mind that they only sent, received, and stored one bit, from one persistent store to another, each of which was capable of store who knows how many bits.
One bit.
How many bits (not bytes, bits) make up an "internet"?
+1 internets to anybody who can give a reasonable answer.
"Hey Bart, pass me another 500ft spool of that rubidium!"
So basically we could have one of these nodes orbiting Mars and communicate with it instantaneously when actually the node orbiting Mars is 18 minutes or more ago but it could communicate to our past the same way..... Oh dear my head just exploded!
Build a Man a Fire, and He'll Be Warm for a Day. Set a Man on Fire, and He'll Be Warm for the Rest of His Life.
If this is really a quantum network, why do they need a fiber to send the information!!!!!!!!!!!!!
So when does the iPhone Qubit come out?
As soon as Apple can patent the idea "for use on a handheld communications device", and it will be called the qBit. Actually, iQ is a much more catchy name.
There is no "I disagree" mod for a reason. Flamebait, Troll, and Overrated are not substitutes.
to read the quantum version of Slashdot.
Sent as ripples into the electromagnetic field. No single photon has been harmed in the process.
Still no ansible I guess.
Ritter acknowledges that the new work is simply a prototype, and one for which numerous improvements are possible. For instance, the transfer of a quantum state between labs succeeded only 0.2 percent of the time, owing to various inefficiencies and technical limitations. "Everything is at the edge of what can be done," he says. "All these characteristics are good enough to do what we've done, but there are clear strategies to pursue to make them even better."
I wish I could publish a 0.2 % yield, or an experiment that worked 0.2 % of the time in Nature! Clearly I'm in the wrong field (but in all serious, getting atoms to communicate through a fiber optic cable is pretty freaking cool.)
Actually, I wrote my thesis on life experience.
China is not amused
April Fool's joke:
http://qbnets.wordpress.com/2012/04/01/chinas-muppet-communique/
I was under the impression that no interactions of QM go FTL. But a lot of posts have been saying that collapse is basically instantaneously. If this is the case than a encumbersome form of FTL communication could be made. Instead of measuring the states, just use positioning. Like optimise the signal so that you can send your message in a byte, then arrange it so each molecule is arranged like a normal binary number of 1s and 0s. Then send a message by just collapsing the corresponding bits. I suppose that this would only work for emergency messages considering reestablishment the entanglement would be a lot slower.
Archos is going to come out with one that has a 3 dimensional qbit array.
It will be 300 qbits long, 50 qbits wide, and 30qbits tall
If you're allowed to use more than 2 dimensions, fold the plane over on itself so that points A and B touch. Now the distance is zero.
Maybe the explanation is in TFA and it went over my head but are the two atoms actually quantum entangled? The process seemed to me more like ordinary synchronization. One photon carrying information (at exactly the speed of light, natch) from one of the atoms to the other, somehow making the quantum value of the recipient the same as the value of the sender at the time it was sent. Isn't "entanglement" more that a copy-and-assign?
Not that maintaining the total information in a qbit over a link could not be valuable: even if you just encoded values in the different spins palimpset-style you could get more than one ordinary bit per photon.
It just seems to miss the whole 'bi-directional spooky action at a distance' thing. What did I miss?
Bent, folded, spindled, and mutilated.
I know a few Apple fans who have an iQ 4.
No, when anonymous posting gets forbidden by law.
The Tao of math: The numbers you can count are not the real numbers.
trapped inside a reflective optical cavity. These atoms communicate with each other by emitting a single photon over an optical fiber. Each atom is a quantum bit — a qubit — and the polarization of the photon
Sounds to me like they're reinventing Flash.
Every end has half a stick.
Since when do the anonymous do care for the law? Being a legion and such.
I've read TFA several times, looked at the diagram and read every single comment in here.
I still don't get it...
How is this technique any better/faster than the current optical fibre method we currently use?
(Disclaimer: IAAP) This is actually not the first realization of a quantum network, that's not the point. Chinese and other researches have already created a quantum network link over up to 16km distance (see for example here: Experimental free-space quantum teleportation (only abstract)). Allthough strictly speaking this was only a 2-point link.
A quantum repeater which is elementary part of a quantum network has also been demonstrated with atomic ensembles.
The new thing here is that their quantum repeater used a single atom in an optical cavity as a photon storage device. The advantage of using only a single atom as qubit storage is the potentially much longer storage time compared to a group of atoms but it is much more difficult to get enough coupling strength to the photon.
This is why they use a cavity which is resonant with the atomic transition used in their setup. But even then you only successfully write a photon in 0.5% of all tries.
But that doesn't actually matter, all you need is to establish an entangled pair before your storage time runs out, so you just to need to repeat the write attempts fast enough.
To clarify: the applications are in quantum key distribution, distribution of entangled qubits for quantum computing purposes, it cannot be used for FTL communication, if ever it will be a very long time before this can be used for superior data transfer (look up quantum dense coding).
This is all basic research to learn how to handle single atoms, how to couple them to photons (so that you can use optical fiber networks) and how to increase fidelity of state preparation and storage time (the stronger you make the coupling to the photons the faster any quantum state will decay due to coupling to the environment). But the main purpose is (to be as cynical as possible) to advance the careers of the principal scientists involved, ensure the flow of grant money and produce phds:)
Seriously the setups they use (ultra high vaccuum, laser cooling etc.) will NEVER be used in any commercial application. You'd need some sort of solid state device where the physics is quiet different and you'd have to do the research all over again.
I want you to build an Ark Right! Whats an Ark? Get some wood build it 300 qbits by 80 qbits by 40 qbits Right! Whats a qbit? Lets see a qbit...I used to know what a qbit was Well don't worry about that Noah When you get that done Go out into the world and Collect all of the animals in the world by twos Male and female, and put them into the ark
Can I use this with my Isolinear Processors?