Wednesday, September 3, 2008

Shut up and calculate!

The Copenhagen Interpretation of QM

"According to Copenhagen Interpretation, before quantum objects are observed, they exist as wavefunctions that can contain a superposition of many mutually contradictory properties. It's only when an observer makes a measurement that the wavefunction collapses, and the particle settles on one of these properties." - Julie Rehmeyer, fq(x) News

Copenhagen Interpretation Wiki Entry

Principles
  1. A system is completely described by a wave function ψ, which represents an observer's knowledge of the system. (Heisenberg)
  2. The description of nature is essentially probabilistic. The probability of an event is related to the square of the amplitude of the wave function related to it. (Max Born)
  3. Heisenberg's uncertainty principle states the observed fact that it is not possible to know the values of all of the properties of the system at the same time; those properties that are not known with precision must be described by probabilities.
  4. (Complementary Principle) Matter exhibits a wave-particle duality. An experiment can show the particle-like properties of matter, or wave-like properties, but not both at the same time.(Niels Bohr)
  5. Measuring devices are essentially classical devices, and measure classical properties such as position and momentum.
  6. The Correspondence Principle of Bohr and Heisenberg: the quantum mechanical description of large systems should closely approximate to the classical description.


Am I a believer of this? I am not sure if I will on the deterministic or non-deterministic interpretation of QM. It has been years already that I have not done any QM in my life. I guess it's time for me to revisit this topic.


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