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.
“Einstein argued that [the phenomenon of nonlocality] violated both common sense and his own theory of special relativity, which prohibits the propagation of effects faster than the speed of light; quantum mechanics must therefore be an incomplete theory. In 1980, however, a group of French physicists carried out a version of the EPR experiment and showed that it did indeed give rise to spooky actions. (The reason that the experiment does not violate special relativity is that one cannot exploit nonlocality to transmit information.)”-The writer of this paragraph are wrong. His error stems from his misunderstanding of what constitutes language. If one simply says that no thing can travel faster than light, they may be correct, granted both the light and whatever ‘thing’ are moving within the same space and that the ‘thing’ is not gravity, which acts at faster-than-light speeds. However, language is not a thing that is transmitted across space between two people. It is a shared symbology based on common experience that allows members to assign the same or similar meaning to a phenomenon common to both of them (either ‘exterior’, objective, or ‘interior’, subjective, and common to both of them either through experience or language). Sometimes that phenomenon is produced by one, sometimes by the other, sometimes by a third person. That phenomenon could be something as ‘simple’ as a raised middle finger or a circled forefinger and thumb. The phenomenon may or may not be common to everyone’s perception or experience. The meaning attributed to it, though, already resides inside those who perceive it.
The End of Science, p. 86, John Horgan
As a simple example, in the United States we use the circled thumb and forefinger with the remaining fingers spread and splayed to indicate ‘okay!’. We speak of the meaning of the sign being ‘conveyed’ or ‘transmitted’ or ‘moving’ between the two parties, but that’s just a misleading metaphor reinforced by our common experience of hearing a shout from down the block or receiving a letter in the mail we know to have come from halfway around the world in two weeks. The only thing moving, however, between the two individuals making and receiving the handsign are the lightwaves being reflected from the circled thumb and forefinger of the one into the eyes of the other. There is literally no transmission of ‘meaning’ or ‘information’.
To demonstrate this, have an American signal ‘okay’ to a Brazilian and then ask each what meaning was ‘transmitted’. The American will say that he was transmitting ‘okay’ to the Brazilian. The Brazilian will say he was receiving from the American the invitation to ‘Eff me’ or ‘Eff you’, depending on what he considered the context to be. The meaning didn’t mysteriously transmute from one to the other message somewhere in the air between the two people. There was no meaning being transmitted at all. The meaning was separately attributed by each party to the sign based, in this case, on dissimilar symbologies sharing a common physical referent.
The same is true whether the means of conveying meaning (again, the metaphor misleads) is through symbolic means of written language, spoken language, signed language; or a more abstract level of symbology such as smoke signals, flags, bent twigs; or the merely mechano/electrical or electronic or photographic transduction and transmittal from one place to another of the ‘stuff’ used to represent language.
The ‘stuff’, whether sight or sound, is shaped by language and is presented to the senses. It is thus available to be received and meaningfully interpreted by another who has the sufficient experience and linguistic ability to make sense of it. This is true whether it is one first grader talking to another about Barney or a philologist working to decipher an unknown language by referring to his existing knowledge of language. In the case of all these media, it is probably true that none of them can be moved faster than light. In this sense there can be no faster than light communication, not because information can’t travel faster than light, and not because it isn’t possible that one person in one location could communicate with another person in another location in less time than it takes for light to travel between the two locations, but because these means used to make perceptible the language cannot be conveyed faster than light.
Now, given a means which is capable of instantaneous effects at a distance, such communication would be possible. Not only is it possible, it has already happened. In the French experiment referenced above, the experimenters needed a means to determine that the experiment had indeed been successful. The means was not the experimental device, but a set of criteria they chose based on their understanding of the phenomenon they were attempting to manipulate. They chose a set of criteria which would give them an unambiguous answer to their question. They all began with a shared set of expectations of what would or would not constitute a successful experiment, then they manipulated (so to speak) the medium and looked for an effect.
Again, the experimenters already knew what to look for which would confirm to them that the experiment was successful. If they didn’t have this shared understanding they would have been even worse off than two people using the okay sign without either knowing the nationality of the other. In that case at least each thinks he knows what the other is signifying. But if one person could try to cause something to happen and another could record and perceive the effect and both could look at that record and separately arrive at the same unambiguous conclusion based on their prior shared understanding, then nonlocalization was used to ‘convey’ information.
Furthermore, it would have been possible for one experimenter to know what to look for and what it would mean and yet keep the other in the dark and still be convinced that the experiment was successful based merely on the observations of a helper who knew neither but could describe what he saw, just as someone could accurately record the sequence of puffs of smoke in a smoke signal system with no idea of what they were being used to signify. In this case there would have been no communication between the two. There was no prior understanding shared that when you see ‘this’ I mean ‘that’, that when you see the photon move in this direction, it’s because I caused its twin to be deflected in that direction.
But when one experimenter can influence one particle and the other particle at a distance is seen by another experimenter to act in a consistent and predictable manner according to an agreed-upon criterion, then communication has taken place and has done do via the experimental device. In this particular case the device happens not to be limited by distance and time in its effects. If I can cause a photon to move at will, then I have in place the basis for a means of communication; all I have to do is arrange a commonly shared meaning to be assigned to whatever permutations of effect I want to cause.
Whatever problems there may be in developing and using the technology, violating special relativity is not one of them.
DNA testing? Actually photons don't have half integer spin, they're Bosons. Only Fermions - a particle, such as an electron, a proton, or a neutron, having half-integral spin and obeying statistical rules requiring that not more than one in a set of identical particles may occupy a particular quantum state - seem to governed by these rules. So if I put a Fermion here in the Good Ol' USA in one quantum state, instantly some other particle in Iraq has to assume a different quantum state. Interesting. Find the ones linked to a prominent politician running for the President of Iraq and tweak.
That is the basis of my question, although the DNA testing was a good option. :-)How would I know to and why would I look in Iraq for the particle/wave with the changed state? Basically, how do you define the limits of your search or how do you predetermine which Fermion to examine??
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.