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Can strings change frequency or stop vibrating?

  1. Apr 6, 2005 #1
    Hello everyone,

    I'm a undergraduate student in the field of physics. I'm working toward a BS in Physics from University of North Carolina at Wilmington.

    I've been thinking about string modes of resonance lately and wonder if the theory allows strings to stop vibrating or change resonance frequency.

    If so, this could explain 'virtual particle' clouds. Imagine:

    A string that is not vibrating could not be detected by modern equipment. However, if that string suddenly started vibrating at the frequency of a photon, then it would seem to us the photon magically popped into existance from nowhere.

    Thanks in advance for your thoughts and responses! Especially those that include math.
  2. jcsd
  3. Apr 6, 2005 #2
    It may be that the only thing keeping the string from collapsing into thin space is that it vibrates so that there is some energy to sustain it.

    What if a string approaches the event horizon of a black hole? Wouldn't the frequency slow down as time dialates?
  4. Apr 6, 2005 #3


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    Time doesn't dilate for an object falling near the event horizon, only for a far-awy observer watching that fall.

    Someone deeper in string theory than I am can correct me, but I believe the frequency modes of a string depend on its momentum, which can vary.
  5. Apr 6, 2005 #4
    I wonder then if there is a 'rest' mode of resonance or modes that cannot be detected by our current technology as particles. Could still work... if strings can change frequency. :smile:

    A similar theory was discussed by Brian Greene in 'The Elegant Universe'. It pertained to the Big Crunch and says that our time is cyclic because of string reaction to being compressed under high gravity.
  6. Apr 6, 2005 #5
    Brian Greene, The Elegant Universe
    "The uncertainty principle ensures that nothing is ever perfectly at rest. All objects undergo quantum jitter..."

    I knew that, I swear! So now I will revise my idea:

    The energy embodied in a string vibrational pattern is a whole number multiple of Planck Energy. Are there energy and/or resonance modes that we can't detect?
    Last edited: Apr 6, 2005
  7. Apr 7, 2005 #6


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    Sure there are, in fact the immense majority of string theory is undetectable. Many of the resonances that a given model could predict in principle are far out of our observational means by something like 20 orders of magnitude.

    Now if the question was, if we had a planckian particle accelerator, are there modes we cannot detect? Well I guess the answer is, be more specific! We can never detect say a gluon in nature, but we can infer its presence by the way other particle/modes react to it.
  8. Apr 7, 2005 #7
    Hi Haelfix,

    While reading your post I got the feeling that maybe 'virtual particles' aren't so virtual. Maybe these particles simply change from being one particle into being another particle (internal string frequency changes), but we can't 'see' the second particle because its too massive. So, to us, the 'virtual particle' disappears and we don't see it again until its energy drops.
    Last edited: Apr 7, 2005
  9. Apr 8, 2005 #8
    Reading again from 'The Elegant Universe', I find that strings themselves can be virtual - leading directly into virtual particles. Oh well... I tried!
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