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2-5: Summary of Part 2

Let us summarize what we have learned in Part 2.

(1)

It has been explained that the particle-wave double nature (duality) which was the greatest mystery in the microscopic world is beautifully unified in quantum mechanics. When a particle of matter or light interacts with other materials, the particle nature manifests itself. When the wave of probability (or wave function) interferes with itself, the wave nature appears.

(2)

The law of classical mechanics (Newtonian equation of motion) is included in quantum mechanics in the form of Ehrenfest's theorem.

(3)

If we measure the position and the momentum of a particle simultaneously, each resultant data would show some dispersion or uncertainty originating from the particle-wave duality and the dispersion would satisfy the uncertainty relation.

(4)

It is impossible for experiment to exceed this uncertainty relation. In this sense, quantum mechanics is considered to be a complete theory.

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