Posted on 08/19/2002 5:59:26 PM PDT by sourcery
Einstein's special theory of relativity strictly forbids anything from traveling faster than the speed of light. A quantum mechanical Bell telegraph, however, may defy this prohibition with a twist -- literally.
The future of telecommunications may hinge on a clever new version of a device from its past, physicists claim. What the Bell telephone is to communication across town or overseas, the Bell telegraph -- named for British physicist J.S. Bell -- may become to communication across the solar system or even the Milky Way.
John Bell first proposed that the strange properties of quantum mechanics might permit subatomic particles to interact instantaneously over distances so vast that signals between the particles had to travel faster than light speed.
"A device that transmits information faster than light speed has always been possible, at least in theory," telecommunications engineering professor and former Bell Laboratories director Ira Jacobs told News Factor. "In practice, such a device would present monumental engineering hurdles that might be overcome by futuristic engineers," he added.
Defying Einstein with a Twist
Einstein's special theory of relativity strictly forbids anything from traveling faster than the speed of light. A quantum mechanical Bell telegraph, however, may defy this prohibition with a twist -- literally.
The so-called up and down "spin" states characteristic of quantum particles would substitute for telegraphic dots and dashes. Spin is a particle's intrinsic angular momentum and may be visualized as a left or right-handed rotation -- or twist -- about an imaginary axis.
In theory, a Bell telegraph could send an instant signal from a particle on Earth entangled with a second particle on a planet light years away -- a special configuration called a "Bell state."
Spooky Physics
"A Bell state is a particular kind of quantum state that describes two particles in which measurement of some quantity in one of the particles instantly affects the distant particle, no matter how far away it is," physicist Daniel Badagnani, a visiting professor with Argentina's National Research Council (CONICET), told NewsFactor.
The very act of observing the Earth-bound particle's spin -- up or down -- instantaneously causes the distant particle to occupy the opposite spin state, a circumstance of quantum mechanics so mystifying Einstein called it "spooky."
Spin "up down up" measurements on the Earth-bound particle instantly become spin "down up down" readings on the distant particle. Assigning dots to "spin up" and dashes to "spin down" leads to a "dash dot dash" with another amazing twist -- the dots and dashes appear instantly to a receiver -- no matter how far away.
Quantum Hurdles
However, future engineers will have to overcome another strange quality of quantum phenomena to construct a functional Bell telegraph. In theory, spin up is a "pure" state, a certainty like the left- or right-handed rotation of a planet or spinning top. In practice, however, quantum spin exists as a high or low "probability" of up or down, never guaranteed until an actual measurement occurs.
Quantum states may be visualized as fuzzy, statistical "waves" that only collapse into hard data after a definitive observation -- hardly the stuff of reliable information. "Due to the probabilistic outcome of the collapse, or quantum measurement, no information can be transmitted through a collapse," University of Missouri physics professor Peter Pfeiffer told News Factor.
'Informed Crazies' Agree
To surmount this hurdle, Daniel Badagnani has searched for an "ingenious setting that could distinguish between the pure state and the statistical mixture," he explained. The prospect of such an innovation heartens National Science Foundation Electrical and Communication Systems program director Paul Werbos.
"I am one of those informed crazies who thinks that there is a 2-to-1 chance we should be able to build something to do what Badagnani wants to do, sooner or later, by exploiting basic phenomena of quantum dynamics and quantum measurement," Werbos told News Factor.
I'm betting against it. Non-locality may be a fact, but taming it for communications is another ballgame. I bet you run up against the wall of indeterminancy. The particles may be intangled, but the process of measuring their state will smother the signal in noise.
just my guess.
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