What is Tachyon: Definition and 31 Discussions

A tachyon () or tachyonic particle is a hypothetical particle that always travels faster than light. Most physicists believe that faster-than-light particles cannot exist because they are not consistent with the known laws of physics. If such particles did exist, and could send signals faster than light, then according to the theory of relativity they would violate causality, leading to logical paradoxes of the ‘killing your own grandfather’ type. Tachyons would also exhibit the unusual property of increasing in speed as their energy decreases, and would require infinite energy to slow down to the speed of light. No experimental evidence for the existence of such particles has been found.
In the 1967 paper that coined the term, Gerald Feinberg proposed that tachyonic particles could be made from excitations of a quantum field with imaginary mass. However, it was soon realized that Feinberg's model did not in fact allow for superluminal (faster-than-light) speeds. Nevertheless, in modern physics the term tachyon often refers to imaginary mass fields rather than to faster-than-light particles. Such fields have come to play a significant role in modern physics.
The term comes from the Greek: ταχύ, tachy, meaning swift. The complementary particle types are called luxons (which always move at the speed of light) and bradyons (which always move slower than light); both of these particle types are known to exist.

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  1. amorphos_b

    Gun with a tachyon bullet paradox

    Gun with a tachyon bullet paradox if you had a device akin to some kind of ‘gun’, which created tachyons and the fired them, perhaps in a beam or some kind of ‘packet’, when they go faster than the speed of light would go back in time. Lets say the ‘bullet’ or beam, went out into the universe...
  2. Sagittarius A-Star

    B Is the gamma-factor for Tachyons real?

    I found in a paper: Source (see page 35 and also chapter 4.1.2): https://scipost.org/SciPostPhysLectNotes.10/pdf Is this correct, and if yes, why? They use the (-+++) convention.
  3. A

    B Unraveling the Tachyon and Photon Debate: Exploring Faster-Than-Light Particles

    A tachyon or tachyonic particle is a hypothetical particle that always travels faster than light. Most physicists believe that faster-than-light particles cannot exist because they are not consistent with the known laws of physics. - Tachyon definition The photon is a type of elementary...
  4. A

    What do you think of this FTL/time travel engine?

    So, I have this idea for the FTL engine for artistic purposes and I wanted to ask if anybody could point out it's flaws. I would greatly appreciate if you were willing to discuss them further. It is just a rough summary, so if you want me to disclose more details, ask away. The idea is as...
  5. BadgerBadger92

    I Are wormholes and tachyon fields unified?

    I read this article. Apparently tachyon fields and wormholes (classical and quantum) are unified. Is there any credibility? I know that with the known laws of physics we can’t go faster than light, and also that tachyons are hypothetical. What is the credibility and what are your opinions? How...
  6. P

    I Tachyon and antiparticle difference

    What is the difference between tachyons and antiparticles?
  7. aethergravitics

    Old dog still learning new tricks

    I have an experimental bent. I am currently trying to expose the tachyon field (replace with quantum field, zero point or whatever term is currently your favorite). Also, currently trying to use a longitudinal wavelength in place of a conductor to reach the ionosphere and tap its electrical...
  8. B

    I Tachyon Helicity: Does Fermion Change Helicity?

    Suppose a Fermion having left-handed helicity travels faster than light between points A and B. Some observers see it traveling from A to B. Some observers see it traveling from B to A (backwards in time). Some observers see it traveling instantaneously (infinite speed). Do any any of these...
  9. Cameron MacGillivray

    B Time travel with tachyons cause infinite dilemma?

    Hi. I am a 13 years old and interested in particle science. I was reading on tachyons and how you could hypothetically send them as signals back in time (not that I'm saying we will manage anytime soon or ever). It got me think about it and I realized something. I'm sure somebody has heard about...
  10. Falcus

    I Exploring Tachyonic Antitelephone and Chronology Protection Conjecture

    Now, first off I am punching well above my weight here but oh well. I am doing an extended project on theoretical methods of space travel and was doing some brief reading in the middle of writing about Miguel Alcubierre's warp drive for hyper fast travel within general relativity. I came across...
  11. Eli137

    Tachyons: Properties, Predictions, Detection

    What are our current predictions, if any, about the properties of tachyons? All I know is that their mass is equal to a complex number and that they speed up as they lose energy. I also heard that they thought neutrinos were tachyons until they fixed the loose cable at the OPERA. Have we...
  12. M

    Tachyon Refraction: Can Massless Particles be Created?

    This is pure conjecture but I was thinking about it and wanted to ask people who know more about tachyons than I do: In a vacuum: Particles with mass can only travel with v < c Mass-less particles can only travel with v = c Tachyons can only travel with v > c If you refract light by passing...
  13. MattRob

    Superluminal (Tachyon) Transformations

    Hey all, I've been reading "Time Travel and Warp Drives" by Allen Everett and Thomas Roman, and the book had an interesting section on Tachyons. At one point it presented a system Leonard Parker (of the University of Wisconsin-Milwaukee) created whereby coordinate transformations for Tachyons...
  14. E

    Question on Tachyon Correlator (Green Schwarz Witten)

    I'm reading through chapter 7 of Green-Schwarz-Witten and I have a problem with the derivation of the M-tachyon correlation function. Basically I'm trying to get 7.A.17 from 7.A.12 and eq 7.A.22 in the appendix of the first volume. Basically I want to prove...
  15. A

    Speed of a tachyon increases as its energy decreases

    I Found This in Wikipedia ''the speed of a tachyon increases as its energy decreases. In particular, approaches zero when approaches infinity'' and My question is How can be this Possible ?! First I know ,When the speed of a particle increase, his Energy will increase Too , No ? Second How Can...
  16. J

    Writing: Input Wanted Future travel with the tachyon field

    Is it possible at all to merge with the tachyon field for a while to obtain FTL travel. Or do I have to go back to the good old standard warp drive?
  17. J

    How close could a tachyon get to a black hole and still escape?

    How close could a tachyon get to a black hole and still escape?
  18. D

    Can a Tachyon Observe Light Traveling Faster Than Itself?

    So, I was thinking about tachyons, and I started wondering about what it would be like to be one. How would the universe look from a superluminal vantage point? Tachyons (should they exist) travel faster than the speed of light. But according to the principle of relativity, a tachyon in a...
  19. P

    Origins of the idea of a tachyon? (and a greeting)

    Hello! Firstly, I'd like to say this is my first post, as I could not find a "new members" sub forum or anything of the sort. I'm a high school student (technically junior, but one year off) with a keen interest in the sciences, particularly in the fields of cosmology, particle physics, and...
  20. D

    Tachyon - assymetry between space and time

    Say, we have empty flat spacetime; there is a lab frame and 2 particles - bradyon and tachyon. While movement of bradyon is stable, tachyon is believed to lose energy because of Cherenkov radiation: http://en.wikipedia.org/wiki/Tachyon#Cherenkov_radiation if it is charged and even if it is...
  21. J

    Tachyon Properties: Time, Length & Special Relativity

    According to special relativity, Would a tachyon's time be imaginary? I saw somewhere that they move backwards in time... Also what would it's length be?
  22. D

    A tachyon is a hypothesized particle that has imaginary mass

    A tachyon is a hypothesized particle that has imaginary mass (imaginary numbers) and moves faster than light speed. I don't believe in it because it can't have imaginary mass, what about you?
  23. P

    FTL Messaging: Does Violating Causality Follow?

    One post posited that if a message were sent to a person traveling FTL and they sent a reply that the person sending the message would receive the reply before the question was sent. If that were possible, receiving the message first would violate causality wouldn't it?
  24. L

    Can a tachyon escape a black hole?

    Assuming a tachyon exists, can one escape a black hole? Now, at the singularity of a black hole, gravity is infinite, right?* Since gravity is infinite, would it not suck in everything, even superluminal particles? On the flipside, since gravity can't exceed the speed of light, is it able to...
  25. C

    Spin 0 Particles: Tachyon & Beyond

    The tachyon has a spin of 0, does any other particle have a spin of 0?
  26. S

    What Happens When Tachyon Collides with Neutron?

    Hey, I am yet to study particle physics or QM but in a few forums i have read that there is a particle called a tachyon which travels faster than the speed of light. I told my mate this and he asked "if you collide a tachyon with say a neutron which is traveling lower than the speed of light...
  27. P

    News Where are the lengthons or the spacions?

    What I want to know about the theory that is supposed to predict fundamental particles of time is: where's the one that predicts fundamental particles of distance? Why aren't people looking for the complementary distance particles? Surely without distance time would not work, so where are the...
  28. C

    Tachyon increases as its energy decreases

    I'm very unfamiliar with them, just curious about the subject, so maybe you can help me out. I know that the speed of a (hypothetical) tachyon increases as its energy decreases, and that it can't go v <= c. Assume that by natural processes, the tachyon loses energy, as most things we know...
  29. D

    Tachyon is said to travel faster than light

    The tachyon is said to travel faster than light because it has a negative squared mass. -How is it possible to have a negative squared mass? Is there a lot more too it? Thanks
  30. J

    Unmasking a Pseudoscience: The Tachyon Detector

    some time ago i found this information http://www.spots.ab.ca/~belfroy/tachyonDetector.html on internet about a supposed "tachyon detector " . I have to confess that i believe this junk until a more deep study of electronics and amplificators led me to conclude that this is only a...
  31. MathematicalPhysicist

    Exploring the Tachyon Vacuum with Expert Barton Zwiebach

    what is it? (i know that the one of experts in this field is Barton Zwiebach from mit).