h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

http://news.bbc.co.uk/hi/english/sci/tech/newsid_2049000/2049048.stm

I was talking to someone a while ago and they told me about this. Does anyone else know any more about this? I'm curious as to how usefull this will actually be, given the limitations. Could we teleport atoms or even people? And if we could teleport people should we, given how the device operates?

It's worth the attempt at developing such a device, but I think it's too early to make predictions about how useful it will be.

I was listening to a radio show the other day about this, and (assuming they could sometime in the future transport people), the question arose as to whether a person's memory would remain intact whilst being transported. The question went along the lines of - seeing as though there is no definitive knowledge of how or even where the memory is stored, then even if atoms were transported and reassembled in exactly the same structure as before, would memory be affected?

I know that it is a far fetched question given that the technology is still very basic . . but I found it interesting.

Maybe they could teleport atoms...

When they can teleport a few bunches of 1,000,000,000,000,000,000,000,000,000 atoms (10^27), and rearrange them in the same pattern they were originally (note the current work doesn't even consider arrangement, just individual state)... they'll be able to teleport people.

I wouldn't worry about it happening any time soon. Or at all, in fact.

If such a device did exist, I wouldn't mind being teleported. Could be handy.

The funny thing about discovery is that, almost by definition, we don't know what will be discovered. We tend to extrapolate from the current state of our knowledge. I think it unlikely that anything as large and complex as a human would ever be teleported in this fashion, the complexity involved is just incomprehensible. It is more likely that some technique that we have not yet even imagined may have the same effect.

The logical extension of the technique here is that you could clone, creating multiple replicas of the original simoultaneously. Scary huh?

Philbert

Teleportation specifically excludes the possibility of replicating something thanks to the Heisenberg uncertainty principle. If you want to move people very quickly it's probably easier to warp space instead of using this approach, as apart from getting the teleporter built and coping with the volume of data you also have to worry about either dissassembling and reassembling someone instantly or else finding a means to keep every atom perfectly static for as long as the transfer takes.

Hmm... I thought the breakthrough was to do with using quantum entanglement to get around Heisenberg's uncertainty principle by allowing duplicates, or somethin' like that...

It's amusing that the article refers to 'trillions and trillions of atoms' making up a human body... trillians and trillians wouldn't even make a speck of dust

There aren't really suitable words in everyday english to describe how many atoms you need, I guess...

They've only actually 'teleported' photons. I say 'only' - it's bloody clever, and extremely odd. It's a bit of a quantum leap (sorry, could'nt resist it) to extrapolate that to, well, anything much in the way of matter. Still, it's got to be better than commuting.

<quote 1> Teleportation occurs through exploiting quantum entanglement, which links the properties of two simultaneously created photons. The researchers disassembled laser light at one end of an optical comms system and recreated a replica 1 meter away.

They found that an encoded signal embedded in an input stream of photons could be entangled with another beam. The beam of photons and the associated signal was then reconstituted in a different part of the lab.

<quote 2> A number of practical applications for entanglement have also been proposed, such as the possibility of sending an encrypted message by means of entangled particles. The knowledge of the correlation between the two particles means that it is possible, at least in theory, to send a coded message using the correlations. What is more, this technique should be completely safe, since if anyone were to intercept the photon en route, the recipient could tell. Briefly, the quantum encryption works by sending a stream of photons to the recipient which are all entangled with photons measured by the sender. By comparing the measurements they made over a normal phone line, say (a string of symbols which is meaningless without the results themselves), they are able to send messages to each other which cannot possibly be intercepted without their knowledge.

Quote 2 is from; http://fergusmurray.members.beeb.net/Causality.html


Is recreating a replica 1 meter away realy teleportation?


Alji

Whether it is teleportation or not might also depend on the timings involved. When the time needed is less that the time it takes light to cross that metre, we have a fundamentally much more interesting phenomena!

The biggest problem with the Star Trek teleporter is what happens if the machine malfunctions and sends a copy of the person to the other end of the line, but never disassembles the original. We then have two Jean-Luc Picards going around being noble. And who inherits the family mansion?

In that case somebody should do what the machine failed to do: disintegrate the original.

Quantum entanglement originated from what I've heard from Einstein who though Quantum theory must be wrong - it was one of a series of situations he announced stating (my words here) "well if quantum theory was true then *this* would happen" - he thought it was ridicuous. Since then, it has been shown to be possible.

This does not *get round* Heisenberg's uncertainty principle. What they have done is create two 'tied' photons with orthogonal (opposite) phase - there is no knowing which one has which polarisation until the system is measured. Then one must be opposite to the other as they were created that way. The so called information was there already at the begining of the experiment.

Heisenberg's uncertainty principle has nothing whatsoever to do with the experiment as far as I can tell.
That merely states that two complimetary properties of a quantum system can only be predicted to a certain degree of accuracy. It essentially comes from the wave properties of tiny systems where the position (or some other function of the entity) is defined not by a precise location but by a wavefunction which is related to a probablilty density function. Ie. you can only state the probablity of a where an electron orbiting an atom is likely to be if it is moving, not its precise location.
Measurement of course pins such things down totally precisely - Heisenberg comes in on the prediction side of things...

sorry - mixing my polarisation and phases up there

I have never trusted the wave/particle duality, the electron producing the photon is a particle and the electron detecting the wave is a particle but does the wave have carry a particle. In other words, you can have a photon at each end but is it the same photon?

Alji

But electrons are waves too...

In fact all particles are waves too, and vice versa.

I think you mean Rikkers. In Star Trek, there was a telporter incident that created two Rikkers, and the environmental differences between the two over several years caused them to have totally different personalities.

I had forgotten that the teleporter incident I made up actually happened in Star Trek.

If noone's ever seen it, there is a book out there somewhere called "The Physics of Star Trek" or something.

It's actually written by a real physics professor and goes into all the science behind the series. It's particualrly interesting when it goes into warp drives and teleporters.
It doesn't totally debunk everything either there are a lot of things from the Original series that have since actually been created.

You cannot just say electrons and photons are either particles or waves or both.
The entities they are can mathematically be described with particle-like or wavelike properties, depending on what and how you measure.
Sometimes they behave like classical particles, sometimes like classical waves.