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Tachyon Speed

  1. Apr 15, 2015 #1

    Garlic

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    Hello,
    I heard that theoretical particles that have negative mass (techyons) are predicted to tend to speed up to infinite, if their energies are low enough. I don't understand why infinite speed instead of 2c (double the speed of light) are predicted?
    Note: I don't know whose/which theory it is. Sorry if my question is irrelevant.
    Thank you
     
  2. jcsd
  3. Apr 15, 2015 #2

    Orodruin

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    Tachyons have negative squared masses.

    Why would you think that the speed should be 2c for a low energy tachyon? Generally, for any particle, ##v = pc^2/E##. All particles satisfy ##E^2 = (pc)^2 + (mc^2)^2## and so if the tachyon has negative mass squared, the energy of the tachyon can be zero. Its velocity would then informally be ##v = pc^2/0 = \infty##.
     
  4. Apr 15, 2015 #3

    Garlic

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    Okay. Thank you. Is there any possibility that a particle has an imaginary mass?
     
  5. Apr 15, 2015 #4

    Orodruin

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    Tachyons generally come with a lot of theoretical problems, such as violations of causality. That is not saying they do not exist, but I believe most physicists would be very surprised if they did.
     
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