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Question (not homework): Quantum phenomena and the Macroscopic world

  1. Feb 25, 2012 #1
    I was doing a question while back about finding the de Broglie wavelength of a bullet with a given mass travelling at a given speed- easy stuff. However, when the result was very similar but slightly larger than the Planck length which I'd stumbled across on my few jaunts through Wikipedia, it got me thinking.

    If the Planck length is the smallest concievable length (according to Wikipedia, we haven't covered it as such in lectures), and a normal day to day moving object has a de Broglie wavelength smaller than this length, is there actually a de Broglie wavelength at all? Would quantum phenomena cease at this point? I would be intrigued to find out more from someone who knows more than I do about quantum physics.

    Thanks and sorry in advance if I've posted this in the wrong place!
  2. jcsd
  3. Feb 26, 2012 #2
    i do not think this is a useful question.

    just know that even if there was a wavelength it is unmeasurable. so it doesn't matter what "actually happens" the fact is that it behaves just like Newton physics.

    just think of quantum physics as a useful tool that gives the right answers. if you get really deep into the theory of that stuff it is just too confusing and will rarely, if ever, be used for the design of practical devices. i never regretted this approach.
  4. Feb 26, 2012 #3
    I thought the whole point of Physics was to find out 'what actually happens'.
  5. Feb 26, 2012 #4
    I think that even if it is times larger, the wave character is still too minuscule comparing to the value of the measurement. For example, the computed distances between maximums of the double slit of bullet is way way smaller than the radius of the bullet, therefore when can only discern the linear combination of probabilities without the interference term (which brought forth by QM).
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