How feasible are superluminal particles?

Nice bevvy of responses there tashja. Maybe you could try getting a response to my #13 - i.e. does 'charged tachyon' make any sense? Janus58 assiduously avoided engaging on that one.

 

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Thanks Tashja, awesome work as always.

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tashja - forget my suggestion in #21. Just did a quick search and below passage from http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html is enough for me:

(emphasis added)
Imaginationon = charged tachyon reads like a reasonable identity to me. The general view even a neutral tachyon would produce 'gravitational Cerenkov radiation' seals it further.

 

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Too late, Q. The request has been honored by our tachyon experts.

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I should have known that once you start a wheel rolling....

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. Anyway again many thanks tashja - always good to get a range of expert opinions. Tachyon hunters are doomed to disappointment imho. On the other hand, theorists speculating/modelling such exotica will probably continue to squeeze out government grants for generations to come.

 

DELETED STUFF UP.

 

How would Tachyons affect the spacetime continuum, [would they create gravity] if they were shown to exist.
Could they possibly be harnessed by an advanced civilisation.

 

In quantum field theory, one can describe hypothetical free tachyons. But a theorem of quantum field theory says all disturbances in quantum fields propagate with speed = c. Thus while formally the tachyonic particles travel faster than c, you can't signal with them faster than c. If this seems like a contradiction from the particle point of view, the tachyons seem to lack an essential property of Newtonian particles -- they don't seem to be localizable as point-like objects.

So quantum field theory, a theory about relativistic quantum physics of point-like objects, says tachyons don't act like points. Bleah. Perhaps a better thing would move them from "hypothetical objects" to "very hypothetical objects."

See section 2.3 of Relativity, Groups, Particles: Special Relativity and Relativistic Symmetry in Field and Particle Physics

https://books.google.com/books?id=iyj0CAAAQBAJ&lpg=PA27&pg=PA24#v=onepage

 

Nice analysis. As usual for you. The reference is great. 2.8 on page 37 is interesting.

 

Hi Paddo,

Wasn't sure if you specifically wanted Q to answer your questions, so I went ahead and forwarded your questions to the experts. Here's their reply:

 

Good work again tashja. A topic where basically it seems there are as many finely-detailed opinions as authorities polled. Referring back to the highlighted text of the passage quoted in #23, such bizarre 'physics' implies a huge overall gravitational footprint, despite negative/imaginary mass of tachyon itself. Then again, here's another view:
http://www.quora.com/How-would-tachyons-interact-with-ordinary-matter-via-the-gravitational-force
And on it could go. I stick with tachyon = imaginationon.

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It's interesting that while Pavel A Cherenkov was co-awarded a Nobel Physics prize for his experimental discovery, in 1934, of the radiation named after him, it turns out the unsung genius Oliver Heaviside wrote quite a bit on 'conical radiation' owing to hypothetical faster-than-light electrons, way back in the 1880's. See the second quoted passage and following, p25 here: https://books.google.com.au/books?i...24&source=gbs_toc_r&cad=3#v=onepage&q&f=false
He was as noted there, wrong in assuming the possibility in vacuo, but nevertheless was the first to predict shock-front EM wave propagation whenever v > c in a medium.
There have been numerous similar cases where credit for earlier work was very slow in coming or not at all.

 

Once again tashja, thanks. Great stuff!

 

From my Post #19

so far, nobody has commented relating to the above.

 

Dinosaur, that was partially addressed in post #28 where they were considered as superluminal quantum particles instead of superluminal classical particles.

 

I have a lot of respect for Martin Gardner. From my Post # 19

I stand by the above until some Poster can refute Gardner's POV.

BTW: Circa 1965 some very bright folks other than my self accepted Gardner's analysis.

 

I think Martin Gardner may have been talking about a 1917 model of FTL communication rather than a quantum field theory of a FTL fundamental particle. The term tachyon was coined in 1967.

In the December 8, 1977 issue of the New York Review of Books, Martin Gardner has this to say about tachyonic communication:

I believe this is not Martin Gardner's original idea, but one based on Tolman's paradox.

This old (1917) argument did not argue against quantum field theory tachyons, but rather against the possibility of signaling faster than light. In quantum field theory, this you cannot do, even if tachyons are real. Martin Gardner's reliance on a Newtonian model of tachyons equates travel speed with signaling speed, but that's not the quantum field theory case.

http://journals.aps.org/prd/abstract/10.1103/PhysRevD.18.3610
http://www.nybooks.com/articles/archives/1977/dec/08/only-joking/
http://journals.aps.org/prd/abstract/10.1103/PhysRevD.2.263
https://archive.org/details/theoryrelativmot00tolmrich
https://en.wikipedia.org/wiki/Tachyonic_antitelephone
https://en.wikipedia.org/wiki/Tachyonic_field

 

Very interesting. I wasn't aware of Heaviside's contribution. I wonder if Cerenkov had read or relied on Heaviside's insight?

 

Hard to say, but if so his/their avoiding giving any credit due had imo a parallel of sorts in Einstein's failure, in his seminal paper "On the Electrodynamics of Moving Bodies." to so much as mention any of the earlier very important contributions from the Likes of Poincare, Lorentz, Michelson-Morley and various others who collectively basically handed SR to him on a platter. Of course there was inevitably much subsequent referencing owing if nothing else than to debate over interpretations etc., but I suspect that initial silence may have been a significant factor in him not getting a Nobel prize for SR. Not that I have studied that issue and historians may disagree.

Anyway while it's entirely possible Cherenkov et al. genuinely were unaware of prior work by Heaviside at the time of discovery, hard to believe that would still be the case by the time a Nobel award was being bestowed in Stockholm.
There remains a sizable cult following for Tesla, yet Heaviside was imo far better grounded especially mathematically: https://en.wikipedia.org/wiki/Oliver_Heaviside
An interesting article by J.D.Jackson on credit misapplied - see in particular part III.A on Heaviside: http://arxiv.org/abs/0708.4249v2
Will belatedly point out my typo in #32 where the second line should have read p125 not p25.