For the first time physicists have achieved quantum entanglement between two large clouds of gas. This achievement means we may live in a future that contains super-fast quantum computers, instant communication over unlimited distance, and even a sort of teleportation.
Among other things, quantum computers will be able to function far more efficiently than the human brain, and to be much, much larger. It’s possible that these experiments are the forerunners of the first genuinely intelligent machines.
Eugene Polzik and his co-workers at the University of Aarhus in Denmark have entangled particles from clouds of gases separated by a long distance, by transferring information from one to another by laser. They managed to entangle about a million million caesium atoms, while the previous record was just four atoms. ?This work should pave the way for a new generation of experiments to teleport states of matter,? says Ignacio Cirac, a quantum physicist at Austria?s University of Innsbruck.
Teleportation will not involve the deconstruction and reconstruction of humans, Star Trek-style. But it will allow the condtion of one set of quantum particles to reproduce more or less instantly in a similar collection of distant particles. In this way a message encoded in photons of light could be transmitted from one place to another instantly. Entanglement will also enable scientists to invent high-speed quantum computing.
Quantum particles such as atoms or photons can exist in distinct states, like the head or tail of a coin. These two states are actually defined by the directions of the atoms? magnetic fields. Such particles can also exist in both states at once in superposition, which is comparable to a coin spinning in the air before it lands.
If we toss two coins at once, their outcomes are independent of each other–if one is heads, the other could be either heads or tails. But two entangled quantum particles have interdependent fates: if one is in a ?heads? state, for instance, the other must be in a ?tails? state. Maintaining this kind of superposition is very difficult, and for any practical applications, entanglement has to include thousands, or even millions, of particles.
Polzik and his team solved this problem by not using full entanglement, where the state of each particle depends on the state of every other particle. Instead, they generated two loosely entangled clouds of caesium gas, one with slightly more atoms in a ?heads? state and the other with slightly more of them in a ?tails? state.
The interdependence of these clouds makes them much easier to maintain and use than just the altered quantum states of a few atoms. It?s impossible, however, to maintain full entanglement of this many atoms for longer than a million-billionth of a second. Polzik?s team can keep their two clouds in a loose entanglement for half a millisecond, but they hope to maintain it for longer in the future. If this can be done, they will have discovered the basis for the quantum computers of the future.
Opinion: This experiment suggests, like others have in the recent past, that faster-than-light communication must be possible. It could very easily explain the radio silence of the universe. Why communicate at low velocities like light speed, when instantaneous communication over unlimited distances is easy?
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