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Why is it important to match frequency to timescale of events?

  1. Jun 11, 2013 #1
    I understand that too long of a time scale won't resolve an event clearly, and too much has the risk of exciting whatever you're trying to measure. Is there some sort of resonant effect when you match, say, a radiation frequency to the time of an event taking place? Specifically I'm applying this to detecting fluctuation phenomena.
     
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  3. Jun 11, 2013 #2

    Simon Bridge

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    Depends on what you want to achieve - the usual approach is to choose the parameters to minimize your uncertainties.

    I'm guessing you are thinking of something like using EM radiation to locate a particle - and you want to be able to measure small changes in position. To get a more accurate position reading, you need a higher frequency, but to-high-a frequency risks disturbing the dynamics you want to monitor?

    But you could be referring to the frequency that data is collected.

    Did you have a specific example in mind?
     
  4. Jun 11, 2013 #3
    I do have a specfic example in mind...in http://arxiv.org/pdf/1110.2097v1.pdf (Temporal correlations of superconductivity above the transition temperature in La2xSrxCuO4 probed by terahertz spectroscopy), they state that "We set the overall scale of so that the loss peak in Fig. 1c is exhibited at a temperature when the probing frequency equals the fluctuation frequency at that temperature." i.e. that at a particular frequency, the lossy fluctuation is identified the most strongly when the frequency of light used to measure the fluctuation matches the frequency of the fluctuation.
     
  5. Jun 12, 2013 #4

    Simon Bridge

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    Hmmm ... it reads a lot like a fudge factor to me - however, it's enough outside my field that I may just not be familiar enough with the methodology. The other way I'd read it is that the probe is detecting what it does by getting a response from the material (a high-temp superconductor) and you intuition that some sort of resonance is involved would be reasonable. If the probe frequency is close to that of the small-scale fluctuations, then these fluctuations would show up strongly. You want to look closely at exactly what is fluctuating, and how the probe works to detect it.
     
  6. Jun 12, 2013 #5
    It is a bit of a fudge factor, and that's acknowledged by the authors. But I'm not sure what about it would be resonating...
     
  7. Jun 12, 2013 #6

    Simon Bridge

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    Me neither - I just skimmed it.
    Find out how the probe part works.
     
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