Quantum "teleportation"

Anyone slightly interested in physics, or cosmology etc, has probably seen the articles / papers posted on the successful experiments proving Quantum Teleportation.

What has been achieved? Has a photon been teleported from one point in space to another, instantly, as the name of this particular quantum effect implies? No, that is not the case, which also is described in the article at SCIAM. Mainstream press though really liked the phrase teleportation and started speculating in moving bodies etc over large distances.

So why am I bitchin' over this? Well probably because I have never seen someone draw some [IMHO*] real conclusions from the evidence brought about by these brilliant experiments. Hang in there, let me try to focus my thoughts on this.

Step 1. Photons are generated at one central source.
Step 2. Two 'beams' of photons make up the experiement.
Step 3. 'Beam' 1 is affected in some way.
Step 4. Somehow, instantly, this change in 'beam' 1 can be detected at 'beam' 2.

Instantly, as in at once, immediately, A.S.A.P, regardless of distance. Regardless of the speed of light. Instantly. Sure would lower your ping** on the 'net, eh?

So, what is strange about this? Photons travel at the speed of light. Einsteins theory of relativity states that the closer to the speed of light a body, object, particle etc travels, the slower that bodys internal clock passes. So when travelling at the speed of light, time shouldn't be an issue, right? Ping.

Again. Since photons are the speed of light, they are at their source and their destination at the same time. Not for us viewers, but for the particle | wave that make up the photon.

If you can accept this, then Quantum "teleportation" shouldn't be so hard to accept and understand. Do something with one photon that is, internally, somehow still in contact with its genesis, therefore still in contact with its 'twin' photon. Look at it this way, and it is almost easy to understand the phenomenon.

Practical applications

Since everyone, and everybody, and their uncle are cheering about the 'teleportation' effect of this experiment, nobody seems to understand at least one practical use. What happens is NOT teleportation. The state of the photons can be transferred over large distances, instantly. It is NOT the photon that is transferred. However, state equals information. And information is money these days. Instant information.

This brings me to what I consider this experiment to be all about: Quantum Communication. The following idea was my first thought when I read the original article.

Build some kind of probe to be placed between, say Mars and Earth. I know nothing of laser technology, therefore this application idea is pure speculation. Let this probe generate two beams of photons, rich in entangled photon pairs. One beam for Mars and one beam for Earth. Build one satellite at each planet, with equipment to manipulate the photons from the probe, and also equipment to detect manipulation. Voila you have instant contact between the two planets. Leave it to JPL to calculate the orbit for the probe [probes maybe].

update 2004-01-27

When an entangled photon pair is generated, the state / spin of the photons are purely random. Only when the original state information from the sending side (Alice) of the experiment is matched against the altered state on the receiving side (Bob), the transmitted information can be pieced together. This requires a normal, sub-lightspeed, means of communication. Crap.

Let's try to find a solution for this. Take something as everyday as polarization. By using polarized light or something equivalent at the photon pair "generator", some photon states should be excluded. If there is a way for Alice to knock the photons to the other state, Bob should be able to detect photons outside of the "polarization range".

My two cents.

- discuss -

*) in my humble opinion

**) 'ping' the time information travels from one computer to another and back on a TCP/IP network, such as the internet

Text (C) A.Hedstrom 1999

Links

Two great books by John Gribbin on the subject of quantum physics:

The first book is from 1985, and is what got me started thinking about these ideas. The other one is from 1996, and takes my reasoning above a lot further.

John Cramer

My favorite quote from the overview: "When we stand in the dark and look at a star a hundred light years away, not only have the retarded light waves from the star been traveling for a hundred years to reach our eyes, but the advanced waves generated by absorption processes within our eyes have reached a hundred years into the past, completing the transaction that permitted the star to shine in our direction." - J. G. Cramer



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