In Physical of the particles, one names tachyon a particle which, if it existed, would move with a supraluminic Speed, i.e. higher than that of the light in the vacuum. Formally, one can see it as a particle which would have a Rest mass imaginary. Such a type of particle does not have however physical reality and is rather a formal indication of a form of instability of the theory (what can arrive for a effective Théorie) which predicts this type of particle. The term tachyon for the first time was used in 1964 by the Physicien Gerald Feinberg.
Etymology
The word tachyon comes from the Greek tachus meaning fast.
Description
A tachyon is a subatomic particle of which speed is always higher than the Speed of light in the Vide. This property is a consequence owing to the fact that its Masse at rest is described by a Imaginary number pure, whereas its energy is measured by a Real number, possibility authorized formally by the equation of the restricted RelativitéOf course here m represents the rest mass. The equation is written by admitting that one can write imaginary pure like square Racine of a negative reality.
In the Quantum theory of the fields, if this particle appears in certain calculations it forever the interpretation of a real particle but is the sign of a Instabilité of the Vide of the model considered. By considering the same quantum theory of the fields but developed around the true vacuum of the theory the contents in particles of the theory are different and the tachyon disappears.
An important example of appearance of tachyon is that of a spontaneous Brisure of symmetry: beyond the critical temperature of transition from phase the Paramètre of order which describes the state of the system spontaneously acquires a not-null value (like the Aimantation in the case of the ferromagnetic Transition for example) and if one then develops the theory around the unstable vacuum (which was stable before the transition however) one sees appearing a tachyonic mode which indicates that the system tends to evolve to one of the new stable vacuums.
Within the more advanced framework of the Theory of the cords, the Théorie of the bosonic cords has such an instability and contains a tachyon in its spectrum developed around the bad vacuum . However it is not easy to determine with precision the true vacuum of the bosonic theory. On the other hand the Théorie of the supercordes which is the realistic base of work to make Phénoménologie does not contain a tachyon in its spectrum.
Causality
The principle of Causality, playing a fundamental role in the Theory of relativity, is stated as follows: " neither Information nor energy can move in a Référentiel galiléen at an high speed at the limiting speed of information of the cause."However the information rate of the cause is precisely the speed limit that the tachyon exceeds (even if the light itself were slower than the information rate of the cause, the definition of the tachyon is to move more quickly than the speed limit, not speed of light). However, Gerald Feinberg presented a mechanism explaining how the existence of the tachyon, and even the possibility of manufacturing detectors of tachyons, would not violate causality. Indeed, by using the formulas of change of reference frame of relativistic mechanics, one notes that for any tachyon, there exist reference frames in which it moves more quickly than the light, but without going up time, and others in which he goes up time.
It should here be understood that the two types of référenciels are in translation each one compared to the others, without none moving more quickly than the light compared to another. The traditional particles are slower than the light in all these reference frames, and the Luxon S go at the same speed in all the reference frames.
The tachyons, can be only supraluminic, but can go towards the past or the future. However if one manufactured a Détecteur tachyons, it would perceive the tachyon only at the time of the collision of the tachyon and the detector, and would not thus know if the tachyon comes from last or of the future. In other words a detector of tachyons is as well a transmitting of tachyons, and to emit tachyons from one apparatus to another cannot be used to transmit a message, since the receiver will not distinguish the tachyons which it receives from those that it emits itself. Even if the tachyons exist, they make it possible to transmit neither information nor energy more quickly than the light.
It is thus useless to utilize loops of causality to solve the problems arising from the Voyage in time of the tachyons, because they cannot cause paradoxes.
In works of fiction
The tachyons are often mentioned in the universe of Star Trek in which the voyage in time is possible. They also appear to justify the voyages or supraluminic transmissions in Hypérion of daN Simmons, in struck down Fondation of Isaac Asimov and the Ways of Anubis of Tim Powers or a landscape of time of Gregory Benford. The generation of waves tachyon is also at the base of the space flights in the video game Tachyon: The Fringe. In K-PAX , an American film of Iain Softley, the Tachyon is means of transport to convey of a planet to another. In a general way, the tachyon is in fiction a Unobtainium, a means easy to justify a generally central element of the intrigue as in the Journeyman series where the hero, travelling in time, thinks initially that is with the tachyons.Other works utilize the tachyons without employing their supraluminic properties. For example in X-Men , the field of tachyons to the property to slice any matter except the Adamantium.
See too
Internal bonds
External bonds
- List of bonds on the tachyons
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