Space Phenomenon

1.8 Tachyons and Faster Than Light Communication

Tachyons are theoretically postulated particles with speeds in excess of c. This is different to erenkov Radiation which is discussed else where. erenkov Radiation concerns particles whose speed is > light < c. As noted nothing with mass can travel faster than light, however the mass of tachyons is considered to be imaginary: i.e. its solution is the equivalent to the -1. The mass is only considered real at speeds greater than c. The reason such speeds are forbidden is a product of the Fitzgerald Lorentz equations:

M=Mo/ 1-(v2/c2)

Where M is the calculated final mass

Mo is the original mass

V is the velocity acclerated to

C is the speed of light in a vacuum

It can be seen that to reach c: (v2/c2 ) could be written as (12/12 ) = (1) now (1-1) = 0.

Now this leaves a finite number, the original mass divided by 0. For the purposes of this conversation and because we are not interested in the mathematics of 1/0 we will assume this leaves the mass as . Simple examinations of the kinetic energy needed to move such a particle to any speed v would cause the energy to tend towards infinity

E=1/2 mv

As m is infinite on the RHS then E must also be infinite on the LHS.

Gerald Feinberg was the first to use the term tachyon, and he named it for the Greek 'tachys,' meaning swift. Tachyons have never been observed in nature or in high energy artificial collisions and thus remain a debated hypothetical particle. One feature of these particles is that they would appear to travel back in time. One of the easiest ways we can examine how time changes for none inertial bodies in relative motion is by applying the very simple Fitzgerald Lorentz equation for time contraction. For simplicities sake we will examine a basic time dilation equation to see how c effects time. Given that:

T=To/ 1-(v2/c2)

Where To is time length according to a stationary clock against a moving clock T.

If we put in a speed in excess of c, lets say 10 times c (warp 2) then we get:

T=To/ 1-(102/12)

T=To/ 1-(100)

T=To/ 99

T=To/9.95 (2 d.p.)

T = 0.1 To the opposite of a normal time contraction in that time is shorter for the clock on the moving frame of reference as observed by the outside observer. Try inputting subluminal speeds and see what you get. As speeds increase towards c the time dilation gets greater as you go past c it gets less and the implication is that a particle travels backwards in time.

Now as we have seen form the first equation relativity forbid any particle to be accelerated from rest or from speeds below c to speeds above c. The energy requirement was infinite. It is therefore postulated that tachyons are created at speeds above c and remain so working in an almost mirror fashion to normal matter, in that they are confined to continually hyper c speeds losing energy would cause them to increase in velocity and to slow the particle to below c would take infinite energy

People are trying to observe this in high energy collisions, telescopes such as the Whipple telescope that look for high energy gamma bursts and erenkov Radiation are trying to see if there are any precursor explosions. These would imply a particle generated that has travelled back to before the explosion and been observed in the telescope.

Experimenters at Berkeley have strong scientific reasons to believe that such quasiparticles really exist, because Maxwell's equations, when coupled to inverted atomic media, lead inexorably to tachyon-like solutions.

Faster than light effects have been observed for a few years now. There are specifically two different kinds of 'faster-than-light' phenomenon have been found during quantum optics experiments. (The tachyon-like quasiparticle that is being worked on at the moment would represent a third such phenonemon.)

First, we have discovered that photons which tunnel through a quantum barrier can apparently travel faster than light. Because of the uncertainty principle, the photon has a small but very real chance of appearing suddenly on the far side of the barrier, through a quantum effect (the 'tunnel effect') which would seem impossible according to classical physics.

Scientific American Homepage

Diagram to Explain Quantum Tunneling

Hypothetical Energy Levels

 

The fact that objects can tunnel through barriers was one of the most surprising consequences of De Broglie’s wave hypothesis and Schrdinger’s Equations. The tunnel effect is so fast that it seems to occur faster than light.

The Einstein-Podolsky-Rosen phenomenon is similar to the second method of faster than light communication. In this phenomenon two distantly separated photons can apparently influence one another’s behaviour at two distantly separated detectors. Prof. J. D. Franson of Johns Hopkins University was the first to theoretically predict this. When twin photons are emitted from a common source they behave in a correlated fashion when they arrive at two distant interferometers as if there has been either communication or influence between them. This phenomenon can be described as a ‘faster-than-light influence’ of one photon upon its twin. Unfortunately due to the intrinsic randomness of quantum phenomena one cannot control whether a given photon tunnels or not, nor can one control whether a given photon is transmitted or not at the final beam splitter. This makes it, presently, impossible to use these phenomenon as faster than light communications.

Scientific American Homepage

Kabat and Princeton University's Gilad Lifschytz believe that the key to the construction and development of blackholes may involve the use of tachyons. The researchers show the use of tachyons might get radiate away high energy particle's excess energy making it possible for them to fal into the blackhole rather than be deflected away. In an article due to appear in The Journal of High Energy Physics, they suggest that particles spit out tachyons as they merge with a black hole.

"These tachyons would be important for the dynamics inside the black hole, but I don't think an observer outside the black hole would be able to see them," says Kabat.


"This paper is very interesting, and it's potentially important," comments Michael Douglas, a physicist at Rutgers University in New Brunswick, New Jersey. "It poses a lot of ideas."

The use of tachyons in the process of matter absorption may solve a very complicated problem with the event horizon of black holes

new scientist 9 January 1999

Tachyon Detection Grid

In Redemption Part 2 (Moore 1991) Geordie utilised a tachyon detection grid to track Romulan D'deridex-Class Warbirds across the Klingon Neutral Zone. This is an entirely appropriate method for detecting invisible ships were it not for the fact that space is so huge. One remembers that in Redemption Part 1, after the attack on the Bortas is repelled a ship loyal to the Duras flees and cloaks it is fired upon by the Hegh’ta. The last Klingon discharge hits after the cloak is engaged and all we see is the shield flash. (One assumes it was a deflector shield not a defence shield given what we learned about D-12 shields and cloaking devices in Generations, that is, shields drop as cloak engages). Now it is easy to lay a net for cloaked ships but across stellar distances with just 20 starships the comparatively slow speed of light would mean that the subatomic particle would only alert you to an enemies presence days or weeks after they had passed. Think of it like sonar, but the signal is not effective if you want to catch the Romulans "in the act" from a star system 5 light years away. It would seem that the writer of the episode Ronald Moore used tachyons for their faster than light capabilities some what like a subspace transmitter, therefore the Federation would have been alerted instantaneously and able to act on the Romulan incursion. The reverted arrow of time being ignored in this case.

Tachyons and M-brane Theory

Two physicists in New Jersey are examining tachyons to solve a conundrum in the explanation of singularities. Over the past decades a new set of theories has raised the hopes of physicists struggling to understand what happens beyond the event horizon of black holes. String theories, for example, portrays black holes and particles as vibrating strings. The disappearance of a particle into a black hole would simply be the result of two different strings being spliced together. Unfortunately there are many severe problems with string and superstring theory even to the point where most scientists have dropped them from consideration. More recently in the last two years physicists have combining these theories into one large "M-theory", which explains a lot about the interior of black hole. Even this theory is fundamentally flawed because even though the curvature around a singularity approaches infinity the trapping of all matter can not be explained under the rules of M-theory. Energetic particles will not merge with a black hole under normal circumstances. This seems to be disconcordant with observation and prediction initially suggesting M-theory to be fundamentally flawed.

"If you send a particle in towards the black hole, and it gets sufficiently close, it needs some mechanism to be absorbed,"
says Daniel Kabat, a physicist at the Institute for Advanced Study in Princeton, New Jersey.
"Once it gets too close to the black hole, it becomes unstable."
Without some way of getting rid of that instability, the black hole would be seen to deflect or emit the particle and this is something that is not observed in nature.

Kabat and Princeton University's Gilad Lifschytz believe they have come to a conclusion as to how to keep M-theory intact, while at the same time explaining how a black hole can capture incident particles. The answer lies in tachyons. Even though Kabat and Lifschytz recognise that nobody has ever seen one, they have shown that tachyons might get rid of a particle's excess energy, making it possible for the energetic particles to be absorbed by the singularity. In an article due to appear in The Journal of High Energy Physics, they suggest that particles spit out tachyons as they merge with a black hole. "These tachyons would be important for the dynamics inside the black hole, but I don't think an observer outside the black hole would be able to see them," says Kabat.

If tachyons really do solve M-theory's problem, physicists may at last have a way to build up a coherent picture of what happens inside a black hole. "You're able to do precise calculations, and such calculations are hard to come by," says Kabat. "It's a pretty compelling picture of a black hole."

"This paper is very interesting, and it's potentially important," comments Michael Douglas, a physicist at Rutgers University in New Brunswick, New Jersey. "It poses a lot of ideas."

Charles Seife New Scientist, 9 January 1999

Scientifc American

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