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Elementary Questions

  1. Jul 13, 2010 #1
    Hi, I'm currently writting an article for people my age (15-18) about Quantum Physics, it's complexity, it's vast uncertainty and it's applications. However, being only young and just halfway through John Gribbin's 'In Search of Schrodinger's Cat', there are several points I would like to raise, but am unnable to explain. I am aware that this may belong in a homeowrk help thread, but I thought I would find the most passionnate and most qualified here. Simple answers please, this is only a simple article! Thanks in advance, PipBoy

    Q: In what way does a particle exhibit both wave like and particle like behaviour? What makes it like a wave, what makes it like a particle?
    Q: Does Quantum Theory agree with Relativity, and what is the definition of Relativity Theory?

    These as a start, thanks.
  2. jcsd
  3. Jul 13, 2010 #2
    For the second question:
    As far as I can tell, quantum mechanics has been successfully combined with special relativity the result being quantum electrodynamics. However, there is to date no widely accepted theory of quantum gravity, which combines quantum mechanics with general relativity, Einstein theory of gravitation. I reccomend you do a quick wikipedia search on these theories to read more.
  4. Jul 13, 2010 #3
    Thank you, thats resolved nicely ^^
  5. Jul 13, 2010 #4
  6. Jul 14, 2010 #5
    For the first question, watching this youtube video may help:

    On the observer part, you can't take "observer" too literlly. Observer just means a measuring device, whether intelligence is involved or not. It involves interacting the particles being observered, not just passively watching them pass by. Interaction free measurements exist, but probably get deeper than what you need to go.

    Here is a video demonstration of the Uncertainty Principle at work, showing actual effects in that case:
  7. Jul 14, 2010 #6


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    Well, I'd count relativistic quantum mechanics as the Klein-Gordon and Dirac equations, whereas QED is really quantum mechanics applied to the electromagnetic field.
    There does exist non-relativistic QED, as well as relativistic QM without using a quantized field.

    So in atomic/molecular physics we tend to distinguish between 'relativistic effects' (such as relativistic momentum corrections, spin-orbit coupling, and Breit-Pauli interactions) and 'QED effects' (such as the Lamb shift).
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