Quantum Dots Might Be Key For Teleportation

prostoalex writes "Researchers from Nanyang Technological University in Singapore have created a model teleportation system using quantum dots. PhysOrg reports that 'tiny clusters of atoms known as quantum dots may be excellent media for quantum teleportation, a physics phenomenon in which information — in the form of a quantum state, a very specific mathematical signature of an atom — can be transmitted almost instantaneously to a distant location without having to physically travel through space.'"

Comments

Biggest Hurdle

[JimboFBX]

Biggest Hurdle so far is figuring out how to stop the quantum pac-man who keeps eating them.

NOT a matter transporter

[Cousarr]

Quantum entanglement is a great way to get information from one location to another at faster than the speed of light but offers no way to transmit matter. Theoretically the precesses here allow for technology like the ansible from Card's Ender's Game series but won't be transmitting ensign Ricky to his death from aboard the starship enterprise. Now, if we were all information-based entities teleporting about using quantum entanglement would be highly feasible.

Re:NOT a matter transporter

[Anonymous Coward]

Your post is almost rigth. Quantum entanglement is used for quantum teleportation but in no way can informaion be transmitted faster than light. In fact in order to be able to teleport somehing, some classical information has also to be exchanged.

Re:NOT a matter transporter

[Seumas]

First of all, I don't want a matter transporter. People are going to insist on using it for an alternate form of transportation. That might seem a fantastic idea, but just wait until some underpaid asshole with a hangover uses the wrong coordinates and doesn't beam you into your office cubicle, but sticks you halfway into a concrete wall in the lobby of your office building.

Now, as for actual matter transportation -- and particularly people -- I've always wondered exactly how that would work. I am not one of those morons who believes that we have a soul or some particular part of our body or supposed spirit that makes us who we are. So - does that mean that simply taking my precise atomic makeup at point A and re-assimiliating it with different atoms over at point B will result in a real, actual me? Or would it be me without whatever makes me myself? I mean, soul and spirit bullshit aside, how could every neuron firing in my brain and every receptor and every blood vessel and capilary and memory stored away in my brain ever be re-produced somewhere else? Surely with so many trillions or quadrillions of atoms that make me up, there will always be some loss. So when you transport me from home to the office, I am a lossy me.

And then, of course, the more you transport, the more you become like a photocopy of a photocopy of a photocopy of a photocopy. Or, if you like another analogy, you go from being Alec Baldwin to Stephen Baldwin to Daniel Baldwin to a pool of primordial goo.

I've also always wondered what would keep someone from just creating many copies of themselves. A transporter would never truly transport you. It would simply map your makeup here and assemble the same thing somewhere else. But that isn't to say that you'd have to destroy the version at point A from which the map came.

So at best, we might some day have matter duplicators. There is no way we would ever have matter *transporters*. If you are going to assemble an orange a mile away, why bother with the energy to destroy a perfectly good orange here, that the duplicate came from? And when it comes to people... can you possibly imagine the indescribable agony you would experience every time you went through the process? They'd confirm that your duplicate was assembled and functional at your destination... and then destroy you at your point of origin. You would somehow be taken apart at the atomic level. Perhaps reduced to a very fine recycleable dust. It wouldn't be harmless and fun like in Star Trek. It would probably be like having a trillion surgical scalpels cutting into you while every inch of your body inside and out felt like it was burning and being shredded and ripped apart.

Re:NOT a matter transporter

[asuffield]

I've also always wondered what would keep someone from just creating many copies of themselves. A transporter would never truly transport you. It would simply map your makeup here and assemble the same thing somewhere else. But that isn't to say that you'd have to destroy the version at point A from which the map came.

Various fundamental results have already been formally proved about quantum physics. One of them is the no cloning theorem, and one of its many implications is that no duplication is ever possible: copying anything on a quantum level must always involve destroying the original.

Another proven result is the no teleportation theorem. This one indicates that quantum matter teleporters are fundamentally impossible. It just can't be done. It's not a problem with scale or accuracy, you cannot even teleport a single atom.

These two theorems are not based on vague arguments, but on the mathematics underlying quantum physics. As such they are iron-clad.

If either a working duplicator or teleporter is ever built, we already know that it will not be based on quantum physics, but on some lower level of physics that has not yet been discovered. This is unlikely to happen in our lifetimes (it takes roughly 100-200 years to move from one level of physics to the next, based on history).

Re:NOT a matter transporter

[Jamu]

I'm not so sure the teleportation theorem does say that. If it's possible to transfer quantum states without measurement, and all you need for teleportation is to transfer these states, then you don't need to make measurements (which is what the teleportation theorem describes). Quantum physics doesn't rule out teleporters. In fact, the cloning theorem suggests that if you do teleport a person, then they are teleported and not destroyed after duplication. That is, if you only transfer their state and don't make measurements in the process of teleportation.

Re:NOT a matter transporter

[Mudcathi]

"Your post is almost rigth." Whath wongth whith ith?

Read the discussion...

[niceone]

The article is pretty light on information, but hte discussion has a pretty thorough description of why this can't (AFAIK) be used to send information, including a link to the wikipedia topic. Maybe they have a way round that, but you can't tell from the article.

Teleporter death

[AmiMoJo]

This reminds me of a question I never found the answer to: if you teleported yourself, would you die and a clone be made?

From the sounds of TFA, the new "you" would not actually be you at all, just a copy. It sounds like your conscious mind would be obliterated and a new one created, although the new one might not be aware of it.

Re:Teleporter death

[WarJolt]

What you are talking about is philosophical issue. With teleportation you no longer exists where you were and you exist where you are now, but thats true as you walk through space. I think the problem occurs when you consider the energy that makes up your matter is part of you.

Let me ask you a question. Isn't it true that your cells are constantly regenerating themselves? The matter you were made up of when you were born no longer is the same matter, but you are still you. So if your qunatum state was duplicated and during the process the original was destroyed then you would still think you are you. Would you still BE you? That just opens a whole can of worms.

The question in my mind is can quantum teleportation bring along your soul? If you don't believe in a soul you have to ask yourself a couple of questions. Are you only you because of that matter that makes you up? The matter that makes you up comes from the stuff you eat. So is the stuff you eat part of you before you eat it? Is it only you when you make food part of your cells and your body? What makes you unconfortable with the idea of your body being made up of different energy? Consider this: Your body is constantly rebuilding itself with new and different energy and disposing of the old parts. Whats the difference?

I bet most people wouldn't step into a teleportation unless the quantum state of your atoms were reconstructed with the SAME energy.

Re:Teleporter death

[stjobe]

Oh, but I disagree :)

"Just" philosophy (as you so eloquently put it) is not at all "meaningless and essentially useless", and quite a few answers can and have been found through philosophy.

However, the questions that are asked in philosophy cannot usually be answered empirically. Neither by observation or experiment, nor by reference to faith or revelation, but rely instead wholly on reason. This should not be taken as evidence that the questions cannot be answered. Logic, for instance, is based purely on reason and it springs, as do so many other fields of study, from philosophy. It also answers a lot of questions.

In fact most of what we now call science was at one time or other found under the heading "philosophy", and only with advances in philosophy did it spring forward as a science in it's own right.

So you see, far from being meaningless and essentially useless, philosophy is in fact inherently meaningful and useful as a tool to explore areas of knowledge science does not yet have the ability to tread. For instance, the philosophy of mind to which this discussion pertains.

Re:Cool.

[Derosian]

A good place to start 'understand' quantum mechanics is to see the double slit experiment. Link.

Re:A little confused...

[asuffield]

I was under the impression that quantum entanglement could not transmit information. If these researchers have actually managed superluminal commmunication, then... wow.

It cannot transmit information faster than the speed of light. It can transmit information when combined with a classical, slower-than-light transfer. It cannot transmit any information without having a classical (non-quantum) information transfer also take place, so the speed is limited by the speed of the classical transfer.

As you would expect, the utility of this is somewhat limited.

Re:Speed?

[asuffield]

"Almost instantaneously" seems to be another way of saying "not instantaneously", which we could have guessed anyway. So why not say how fast it actually is?

It's not measurable (really! to measure it would require a system that can transport information faster than light, and that's not possible so far as we know) and not really important. You teleport an entangled blob of quantum state, which arrives "almost instantaneously". You cannot do anything with it until you receive the companion classical information from the transmitter, which you need to "unpack" that blob of quantum state and extract the teleported information from it. The effective speed of the process is precisely the same as the actual speed of your classical (non-quantum) slower-than-light information channel, and that's the important part.

Faulty assumption

[cat_jesus]

Assuming that you can determine when the quantum waveform collapses

This is the faulty assumption.

Think of of entanglement this way. You have two roulette wheels and they are "entangled". What this means to the roulette wheels is that they are spinning and the marbles are bouncing along inside them synchronously(I know they'd be at right angles but being the same value works well for the visualization). So you split them up and one roulette wheel is in another galaxy and the other is here. Both are spinning and the marbles are still bouncing around in sync. If you stop one, the other keeps going. If you stop them at the same time the marbles will have the same value. But the problem is the one you assume away. You cannot tell that the other roulette wheel has stopped.

In QE, if you attempt to observe the entanglement, you make it collapse. You can't tell what the state of the particle is without destroying the entanglement.

IINAQP and I could be wrong. But this is my understanding and my cousin who is a Physicist tells me I have an accurate, if rudimentary, understanding of this particular phenomenon.

I wish you were right.

Re:Cool.

[Davey McDave]

That's basically quantum computing for you. You can get them involved in such a state that they can influence one another even though they're not even next to one another (action at a distance). Hence they're sort of invisibly entangled within one another, if you mess around with one the other will instantly change. This is pretty great though, because if you can get all these things to represent a calculation, and act upon it, it instantly changes at this other place you can read them. Even better, if someone else tries to read it at the other place it'll show up back at the origin.

Quantum isn't really a buzzword, it actually means that it's taking advantage of the fact that energy is discrete rather than continuous. It's supposed to be used in opposition to classical or Newtonian mechanics, which assumes that energy is continuous, and has a huge amount of crazy consequences.

If you're REALLY interested in learning about quantum mechanics I'll one up the sister post and recommend you some of Feynman's lectures. In the first video here he whips through almost the entire history of physics and why QM is different: http://www.vega.org.uk/video/subseries/8

Re:How much POWER will that take?

[vertinox]

It depends on what kind of nuclear reactors.

Are we talking about Africa or European reactors? And secondly how would two reactors carry the quantum dots? With a line or a strand of creeper?

Re:Cool.

[Rallion]

And, I've found, a good place to stop understanding quantum mechanics is looking into more advanced variations of the experiment.

Re:How much POWER will that take?

[ethicalBob]

Obviously it would take 1.21 gigawatts

(oh, wait... only if it's encased in a Delorean)

Re:How much POWER will that take?

[Tumbleweed]

The biggest difference between the gate system and Trek's teleporters is the distance involved. That and the creators.

Whereas, the biggest difference between Star Trek and Stargate SG-1 is that Star Trek stole from westerns, and Stargate SG-1 stole from every sci-fi show that's ever been shown. (I'm not saying they did it badly, though.)