When David Rice, a character played by Hayden Christensen in the new movie Jumper, first discovers that he can teleport around the world at will, he makes a series of interesting choices.
First, it's to save himself from drowning by imagining himself in the warmth and safety of a familiar library. But Rice's desires soon grow darker, and before long he has gone from innocent experiments to robbing banks and joytripping around the world.
"Regular people aren't heroic," says the film's director, Doug Liman, "and I wanted the film to feel honest and realistic."
Realistic? In a science-fiction movie about teleporting "jumpers" who, thanks to a genetic mutation, can leapfrog to any spot on the planet in the blink of an eye?
Sure, Liman concedes, there are plenty of scenes in which the fictional world of Jumper favors fantasy over physics. But the idea of teleportation — traveling instantly from one spot to another without actually moving through the space in between — is just as at home in the physics lab as in the movie studio.
Science fiction vs. science
In science fiction, teleportation usually works in one of a handful of ways. Sometimes it comes down to superior mental powers, or maybe the ability to leap through a parallel universe or an extra dimension.
Then there's the transporter from Star Trek, a teleportation machine that "scans" the person to be transported and "beams" him up or down as a "matter stream."
Real-world teleportation, however, is based in the bizarre laws of quantum physics, which govern the behavior of subatomic particles such as photons and electrons. Starting in 1993, scientists realized that if conditions were just right, a phenomenon called "quantum entanglement" might be used to bounce fundamental information about particles — their quantum state — across space instantaneously.
Within a few years, scientists were announcing that they had achieved this "quantum teleportation," shifting the energy state from one electron to another, for example, in literally no time at all. In one experiment last year, European scientists teleported quantum information over 89 miles, between two of the Canary Islands.
That's not just a neat party trick, but it's not going to get Captain Kirk back aboard the Enterprise after one of his adventures, either. "First of all, we're not teleporting physical objects, we're sending information," says Jeff Kimble, a physicist at the California Institute of Technology in Pasadena and one of the pioneers of quantum teleportation.
For subatomic particles, sending information is as good as sending the particle itself. But it won't do much good for teleporting a person made up of an astronomical number of quantum particles, especially since the would-be traveler would have to be first broken down into his or her constituent particles.
Still, mastering entanglement could lead to new technologies such as super-powerful, super-secure quantum computers, Kimble says. "Teleporting people is complete science fiction, but this is real science, and hopefully useful technology for our society."
Wormholes would require 'negative energy'
The title characters in Jumper rely on yet another popular teleportation scenario: They're able to create and travel through wormholes, or shortcuts through the fabric of the universe.
And like quantum entanglement, the idea of wormholes comes straight out of theoretical physics.
"It's actually a famous solution to the Einstein field equations of general relativity," says Max Tegmark, a cosmologist at the Massachusetts Institute of Technology in Boston. "The idea is you have these two black holes connected together by a wormhole. You jump into one of these black holes, and you come out of a 'white hole' somewhere else at the same time."
The problem with wormholes? "We know that they don't exist," says Lawrence Krauss, an astrophysicist at Case Western Reserve University in Cleveland and the author of The Physics of Star Trek. "The mouth of the wormhole would actually collapse to a black hole, and you'd never be able to get out of the mouth."
Wormholes could exist, he says, only "if you had what's called negative energy to keep the mouth open, and we know that no normal matter does that."
'These awful laws of physics' slow us down
Says Tegmark: "Most people do think that wormholes are unstable, but nobody has managed to prove rigorously that you can't somehow stabilize them with some weird kind of dark energy. So we're still in this tantalizing situation where we're assuming it's impossible, but if you push it, we can't prove it.
"My guess is that it's probably impossible, but the jury is still out."
As for the appeal of teleporting, Krauss says that at least is straightforward: "People yearn," he says. "We're trapped by these awful laws of physics that tell us we can't get anywhere we want to get immediately." Teleporting, he says, would give us a taste of freedom not usually allowed in the physical world — kind of like the movies themselves.