Arrow of Imaginary Mass/Mess, The

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neufer
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Arrow of Imaginary Mass/Mess, The

Post by neufer » Thu Nov 11, 2010 2:40 pm

Tacky, a. [Tack a spot, Cf. Techy,]
1. In poor taste; appearing cheap; gaudy; unstylish.
2. Tactless; in poor taste; -- used to describe behavior.

Techy, a. [ {graduate of M.I.T.} from OE. tecche, tache, a habit, bad habit, vice,
OF. tache, teche, a spot, stain, blemish, habit, vice, F. tache a spot, blemish;
probably akin to E. tack a small nail. :evil: ] Peevish; fretful; irritable.
http://en.wikipedia.org/wiki/Tachyon wrote:
<<A tachyon (Greek: ταχύς, takhus, "swift" + English: -on "elementary particle") is a hypothetical subatomic particle that moves faster than light. In the language of special relativity, a tachyon is a particle with space-like four-momentum and imaginary proper time. A tachyon is constrained to the space-like portion of the energy-momentum graph. Therefore, it cannot slow down to subluminal speeds. The first description of tachyons is attributed to German physicist Arnold Sommerfeld (5 December 1868 – 26 April 1951) who was nominated a record 81 times for the Nobel Prize in Physics, and served as PhD supervisor for more Nobel prize winners in physics than any other supervisor before or since.>>
http://en.wikipedia.org/wiki/Tachyon_condensation wrote:
<<In particle physics, theoretical processes that eliminate or resolve particles or fields into better understood phenomena are called, by extension and metaphor with the macroscopic process, "condensation". In particular, tachyon condensation is such a process that eliminates the tachyon, which many physicists believe does not exist.

Tachyon condensation is a process in which a tachyonic field—usually a scalar field—with a complex mass acquires a vacuum expectation value and reaches the minimum of the potential energy. While the field is tachyonic (and unstable) near the original point—the local maximum of the potential—it gets a non-negative squared mass (and becomes stable) near the minimum.

The appearance of tachyons is a potentially lethal problem for any theory; examples of tachyonic fields amenable to condensation are all cases of spontaneous symmetry breaking. In condensed matter physics a notable example is Ferromagnetism; in particle physics the best known example is the Higgs mechanism in the standard model that breaks the electroweak symmetry.

Although the notion of a tachyonic imaginary mass is troubling, what is really being quantized here is the scalar field; even for tachyonic quantum fields, the field operators at spacelike separated points still commute (or anticommute), thus preserving causality. Therefore information still does not propagate faster than light. Also the "imaginary mass" really means that the system is unstable and that solutions will grow exponentially, but not superluminally (there is no violation of causality). Tachyon condensation drives the physical system to a stable state where no physical tachyons exist. The zero value field is at a local maximum (i.e., Jenkins Hill) rather than a local minimum (i.e., Goose Creek) of its potential energy, much like a ball at the top of a hill. A very small impulse (which will always happen due to quantum fluctuations) will lead the field to roll down with exponentially increasing amplitudes toward the local minimum (i.e., Goose Creek). Once the tachyonic field reaches the minimum of the potential, its quanta are not tachyons any more but rather have a positive mass-squared, such as the Higgs boson.
Image
26-dimensional bosonic string theory
Tachyon condensation in string theory

In the late 1990s, the Indian string theorist Ashoke Sen conjectured that the tachyons carried by open strings attached to D-branes in string theory reflect the instability of the D-branes with respect to their complete annihilation. The total energy carried by these tachyons has been calculated in string field theory; it agrees with the total energy of the D-branes, and all other tests have confirmed Sen's conjecture as well. Tachyons therefore experienced a comeback in the early 2000s. The character of closed-string tachyon condensation is more subtle, though the first steps towards our understanding of their fate have been made by Adams, Polchinski, and Silverstein, in the case of twisted closed string tachyons, and by Simeon Hellerman and Ian Swanson, in a wider array of cases. The fate of the closed string tachyon in the 26-dimensional bosonic string theory remains unknown, though recent progress has revealed interesting new developments.>>
Techy Art 'who cannot slow down to subliminal speeds' Neuendorffer

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owlice
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Re: Arrow of Imaginary Mass/Mess, The

Post by owlice » Thu Nov 11, 2010 3:57 pm

neufer wrote:The first description of tachyons is attributed to German physicist Arnold Sommerfeld (5 December 1868 – 26 April 1951) who was nominated a record 81 times for the Nobel Prize in Physics, and served as PhD supervisor for more Nobel prize winners in physics than any other supervisor before or since.>>
WOW. How is it even possible to be nominated 81 times?! And wow for his supervisory skills as well! The two together are just astounding!
I feel so unworthy now.
neufer wrote: The zero value field is at a local maximum (i.e., Jenkins Hill) rather than a local minimum (i.e., Goose Creek) of its potential energy, much like a ball at the top of a hill. A very small impulse (which will always happen due to quantum fluctuations) will lead the field to roll down with exponentially increasing amplitudes toward the local minimum (i.e., Goose Creek).
lol!
In the late 1990s, the Indian string theorist Ashoke Sen conjectured that the tachyons carried by open strings attached to D-branes in string theory reflect the instability of the D-branes with respect to their complete annihilation. The total energy carried by these tachyons has been calculated in string field theory; it agrees with the total energy of the D-branes, and all other tests have confirmed Sen's conjecture as well.
De brain is taxed; time for more coffee.
A closed mouth gathers no foot.

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neufer
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Re: Arrow of Imaginary Mass/Mess, The

Post by neufer » Thu Nov 11, 2010 4:45 pm

owlice wrote:
The first description of tachyons is attributed to German physicist Arnold Sommerfeld (5 December 1868 – 26 April 1951) who was nominated a record 81 times for the Nobel Prize in Physics, and served as PhD supervisor for more Nobel prize winners in physics than any other supervisor before or since.>>
WOW. How is it even possible to be nominated 81 times?! And wow for his supervisory skills as well! The two together are just astounding!
Even Susan Lucci finally one after 18 failed nominations.
(Or was that Nobel Prize in Literature?)
owlice wrote:
In the late 1990s, the Indian string theorist Ashoke Sen conjectured that the tachyons carried by open strings attached to D-branes in string theory reflect the instability of the D-branes with respect to their complete annihilation. The total energy carried by these tachyons has been calculated in string field theory; it agrees with the total energy of the D-branes, and all other tests have confirmed Sen's conjecture as well.
De brain is taxed; time for more coffee.
It makes perfect Sen's to me.

Didn't you watch the string section of Toot, Whistle, Plunk And Boom :?:

(I don't even know why I bother handing out homework sometimes :!: :| )
Art Neuendorffer

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owlice
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Re: Arrow of Imaginary Mass/Mess, The

Post by owlice » Thu Nov 11, 2010 5:09 pm

As if I don't have enough homework as it is...!!!
A closed mouth gathers no foot.

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