Information AboutTachyon |
| CATEGORIES ABOUT TACHYON | |
| string theory | |
| subatomic particles | |
| time travel | |
| hypothetical objects | |
| faster-than-light travel | |
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BASIC PROPERTIES (FROM A SPECIAL RELATIVITY PERSPECTIVE) As mentioned above, a tachyon is a particle with space-like Four-momentum . If its Energy and Momentum are Real , its rest Mass is Imaginary . It is difficult, for instance, to interpret exactly what a Complex -valued mass may physically mean. One curious effect is that, unlike ordinary particles, the speed of a tachyon ''increases'' as its energy decreases. This is a consequence of special relativity because the tachyon, in theory, has a negative squared mass. According to Einstein, the total energy of a particle contains a contribution from the rest mass (the "rest mass-energy") and a contribution from the body's motion, the kinetic energy. If ''m'' denotes the rest mass, then the total energy is given by the relation : We take this relation to be valid for either tachyons or regular particles ("tardyons"). For ordinary matter, this equation shows that ''E'' increases with increasing velocity, becoming arbitrarily large as ''v'' approaches ''c,'' the Speed Of Light . If ''m'' is imaginary, on the other hand, the denominator of the fraction must also be imaginary to keep the energy a real number (since a pure imaginary divided by another pure imaginary is real). The denominator will be imaginary if the quantity inside the square root is negative (recall the problem imaginary numbers were invented to solve), which only happens if ''v'' is larger than ''c.'' Therefore, just as tardyons are forbidden to break the light-speed barrier, so too are tachyons forbidden from slowing down to below light speed. The existence of such particles would pose intriguing problems in modern physics. For example, taking the formalisms of Electromagnetic Radiation and supposing a tachyon had an electric charge—as there is no reason to suppose ''a priori'' that tachyons must be either neutral or charged— then an accelerating tachyon must radiate electromagnetic waves, just like ordinary charged particles do. However, as we have seen, reducing a tachyon's energy ''increases'' its speed, and so in this regime a small acceleration would produce a larger one, leading to a run-away effect similar to an Ultraviolet Catastrophe . Some modern presentations of tachyon theory have demonstrated the possibility of a tachyon with a real mass. In , such a particle would be a "tachyon" by virtue of its apparent superluminal velocity, even though its rest mass is a real number. CAUSALITY The property of has not been obtained within a Quantum Field Theory , but has to be imposed by hand. At the very least the principle of Special Relativity would have to be discarded. Other avenues of speculation involve Parallel Universe s. One can imagine a scenario in which sending energy or information back in time causes history to diverge into two distinct tracks, one in which events reflect the altered information and one in which they do not. In the theory of General Relativity , it is possible to construct spacetimes in which particles travel faster than the speed of light, relative to a distant observer. One example is the Alcubierre Metric . However, these are not tachyons in the above sense, as they do not exceed the Speed Of Light locally. FIELD AND STRING THEORIES In . The Higgs Mechanism is an elementary example, but it is important to realize that once the tachyonic field reaches the minimum of the potential, its quanta are not tachyons anymore but rather Higgs Boson s that have a positive mass. It must be noted that even for tachyonic quantum fields, the field operators at spacelike separated points still commute (or anticommute). Tachyons arise in many versions of String Theory . In general, string theory states that what we see as "particles"—electrons, photons, gravitons and so forth—are actually different vibrational states of the same underlying string. The mass of the particle can be deduced from the vibrations which the string exhibits; roughly speaking, the mass depends upon the "note" which the string sounds. Tachyons frequently appear in the Spectrum of permissible string states, in the sense that some states have negative mass-squareds, and therefore imaginary masses. TACHYONS IN FICTION In the '','' ships fire "tachyon pulses" at one another, disrupting the targets' "shield harmonics" and thereby allowing Transport through the shields. In general, tachyons are a standby mechanism upon which many Science Fiction authors rely to establish faster-than-light communication, with or without reference to causality issues. For example, in the '' Babylon 5 '' Television Series , tachyons are used for real-time communication over long distances. Another instance is Gregory Benford 's novel '' Timescape '', winner of the Nebula Award , which involves the use of tachyons to transmit a message of salvation back in time. Likewise, John Carpenter 's horror film '' Prince Of Darkness '' uses tachyons to explain how future humans send messages backward through time to warn the characters of their impending doom. By contrast, Alan Moore 's classic Graphic Novel '' Watchmen '' features a character who uses "a hail of tachyons" broadcasting from space to muddle the mind of the only person on Earth capable of seeing the future. Robert J. Sawyer 's novel ''Flashforward'' features the invention of a Tachyon- Tardyon Collider, allowing experiments which previously required large particle accelerators to be performed in a machine about the size of a microwave. Additionally, a space probe is launched with a tachyon transmitter, allowing it to send information to earth at Faster-than-light speeds. Tim Powers 's novel '' The Anubis Gates '', winner of the Apollo Award in 1987, involves the use of tachyons to initiate time travel. '' episode "Explorers", a tachyon stream was used as an (accidental) means to propel a Sail ing ship to warp speed. In Jack Williamson 's novel '' The Humanoid Touch '', the humanoids are said to have tachyonic ships propelled by "rhodomagnetic" science. The word "tachyon" has become widely recognized to such an extent that it can impart a science-fictional "sound" even if the subject in question has no particular relation to superluminal travel (compare '' utilizes "tachyon gates" for superluminal travel but gives no exact explanation for the technology, and the MMORPG '' Eve Online '' features six types of "Large Tachyon Lasers", technically a contradiction since by definition, Laser s emit light— Photon s, not any kind of hypothetical tachyon. The Tom Baker -era '' Doctor Who '' story " The Leisure Hive " features a race called the Argolins who utlise tachyons for a cloning-like procedure and for "illusions" as such. The Argolin Pangol explains, "Tachyons travel faster than light. A tachyon field can therefore be made to reach point ''B''—that visidome, say—before its departure from point ''A,'' the Generator." Romana says that the Time Lord s "abandoned tachyonics when we developed warp matrix engineering". Mario Puzo 's novel '' The Fourth K '' uses tachyons as an argument for the establishment of new scientific procedures. In the Korean version of MapleStory , items called tachyons are required to complete a certain high-level quest. In '' Red Dwarf '', a reference to tachyons is made to describe the form in which a holoship is able to travel as super-light particles through '' Wormholes '' and '' Stargate ''s. SEE ALSO
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