Monday, January 26, 2009

A Very Long Entanglement

A team at the University of Maryland was able to teleport the information of a charged a charged atom across a meter of distance last week. The actual atoms didn't move, however information about it moved a large distance instantaneously, as in faster than the universal speed limit, the speed of light. Though this might sound impossible, under the funky laws of quantum mechanics, weird things that don't make classical sense are commonplace. This wasn't even the first time scientists were able to influence distant particles instantaneously, but it's the first time an entire atom's information have been teleported.

The subatomic world of quantum mechanics is full of bizarre happenings and spooky events. One of the strangest goings-on is how particles can exist in multiple places at one time. In the very tiny world of quantum mechanics, particles don't necessarily inhabit a single point in space, but exist as a wave of probability. These waves express where a particle is likely to exist at any given moment. Only when someone measures the locations and states of these particles, do their wave functions collapse and the particles resolve themselves into single points.

When two waves overlap, the particles can become "entangled" and that's when things can get really spooky. When two particles are entangled their traits become mixed up and indistinct. Only when someone measures one of them do they resolve themselves into their original distinct particles. Up until that moment, they exist as both particles with a certain probability attached to it.

Scientists can isolate each particle's wave function, and with careful manipulation, actually move them apart from each other. After the two are separated by a wide distance, scientists then measure one particle collapsing its wave function. When this happens, the other particle resolves itself at precisely the same moment as well. The two particles essentially communicate with each other at precisely the same moment in time, across great distances. The reason that no laws of physics are broken by this instantaneous linkup, is because the information needed to interpret the results still has to travel by normal means.

Though this kind of "teleportation" won’t help Mr. Spock beam down to a planet surface, this transfer of information holds a lot of promise for quantum computers and secret codes. Using entanglement, information can be securely transferred between two points a great distance away.


2 comments:

  1. what does this mean "the information needed to interpret the results still has to travel by normal means."?

    If I set up a communication device (using the system as described above) and two observers are 1 light year apart. Observer 1 encodes a message in entangled Atom A. Observer 2 attempts to read the corresponding entangled Atom B. Will it then take "Observer 2" 1 year interpret the results.

    I don't get it.

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  2. In a way. Because the two observers are a light year apart, it would take a year to interpret the results. The two separate observers would receive the information, but since the two are a light year apart, it would take (at least) a year for them to communicate the results with each other. Even though it seems like the information travels faster than the speed of light, it would take a year to know it.

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