Friday, July 08, 2005


I just read an interesting article on that scientists have successfully caused a light beam and the quantum state of a cesium ion to teleport a significant distance. The article is actually about a somewhat fanciful book by David Darling called Teleportation – The Impossible Leap, which has aparently just come out. While I was trained in classical (i.e., non-quantum) general relativity, I do know enough about quantum mechanics and quantum gravity to know that in some sense teleportation is possible. The kicker is whether it would be possible to teleport the trillion trillion atoms in your body at all and if so, if you would still be you when you get there. Still, it's an intriguing idea, and good science fiction always has a basis in the extrapolation of science fact. I knew I was in the right field when I ran across a published paper on general relativity titled "The Physics of Warp Drive." The author had shown how you can get faster-than-light travel without violating Einstein's theory. Cool stuff, but that's for another essay.

On the surface teleportation seems like a good thing, and like most technologies, to a certain extent it is. Remember, though, that a good science fiction writer should consider the consequences of any new technology he introduces. As an exercise, then, let's consider this case. First of all, there are two forms of teleportation. The "Star Trek" variety allows you to beam yourself to any location without any equipment at the receiving end.* There are some obvious advantages to this -- you can get to orbit quickly and cheaply, without the need for shuttlecraft (which, by the way, was the reason Gene Roddenberry employed this device). If the teleportation has no range limitations, then you obviously no longer need spacecraft. You also no longer need any large-scale weaponry, either, though. Just teleport a nuke to your enemy's most sensitive strategic areas (or population centers) and set it off. There's no defense. It makes for very short wars that generally destroy civilization fairly rapidly. You might hold off doomsday the way we do now via a policy of "Mutually Assured Destruction," but this policy hinges on the notion that the other guy doesn't want to die any more than you do. As we have recently learned rather graphically, there are plenty of people in the world who don't care if they die, so long as they get to you. Eventually, the widespread use of this type of teleportation would cause the total destruction of society, unless you can figure out some clever way to limit it.

This is not the kind of teleportation our real-world scientists are studying, however. The main difference between the two systems is that this second kind of teleportation requires equipment and raw materials at the other end. Assuming that we can't transmute one kind of matter to another, that means that we are going to need stockpiles of pretty much every element on the periodic table at our destination. Something is going to have to assemble the right amounts of each material, and then finally the "quantum state inducer" could snap everything into place by making the quantum state of the material at the destination match that at the origin. While this last part is instantaneous, the rest of it takes time. In fact, if you are traveling over interstellar distances, you're going to need to send a light-speed signal to the receiver to give instructions on how much material to assemble into the "receiver chamber." Maybe if we can figure out a way to send commands via teleportation (which shouldn't be too hard, compared to the task of sending a human), then we can make this step instantaneous, too. We can't avoid the need for an initial sub-light trip to the destination to set up the equipment, however. This means that our interstellar civilization will grow very slowly, but once inital contact is made, the "colonies" will become completely integrated with the homeworld almost immediately. All you need is one receiver and the base stock of supplies and you can teleport the other receivers you need.

If we assume that you can't take over someone else's teleportation receiver, rival interstellar empires are possible with this version of the technology, but are still very difficult to defend. Your entire defense depends upon preventing the enemy's initial sub-light receiver-building ship from getting to your planet. The first time they land something and get it operating, you're in trouble. On the other hand, you can't just teleport a bomb anywhere you want. You still have to send agents into the target area to set up the receiver, so why bother? Why not just have your agents bring the bomb? I can imagine that embassies for even allied governments would be very closely guarded and located a long way from your strategic targets. Otherwise, all the enemy needs to do to take you out is sacrifice their embassy.

There is a deeper aspect to this technology than simple teleportation, however. The device is not really a teleporter -- it's a duplicator. When you step into the transmitter, all the machine does is cause the material at the other end to assume your quantum state. Nothing happens to you. One could argue that since the duplicate created at the other end has the exact same quantum state as you do, it should have the exact same memories, physiology, etc. In effect, it is you, and it will remember having stepped into the transmitter and stepped out onto a new world. But what about the original version of you that was left behind? That copy obviously doesn't go anywhere and doesn't get to share in the experience of the new world. Should the transmitter booth include a small X-ray laser that vaporizes the original you when the teleportation is complete? Or should we just let our multiples multiply? And what if you needed a scouting report from a distant world? You step into the machine, have your duplicate do the scouting, then the duplicate duplicates himself, and has his double (your triple, though with different experiences than the original you) brief you on what he saw. But remember, that third version of you thinks he is you. You are the imposter and an uninformed imposter at that. Why should he tell you anything? Why shouldn't he just bump the original you off and take your place? Or how about this: What if all you can do is change the quantum state of the brain, so you need an actual human in the receiving booth -- a human whose personality will be wiped out by the transmitter?

Intricate consequences from what seems to be a simple idea. And those consequences hold a great deal of potential for conflict and therefore stories. This is what I find fun about writing science fiction!

*Yes, I know that in Star Trek you are "beamed" at the speed of light instead of instantaneously, but the effect is the same.

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