Question:
Dear sir,
What is a k-space? Is it a real space or only a geometrical
presentation of the discrete eingenvalues of the schrodinger
equation or an inner property of a plane wave? Another question related
to this is that, is the wave function capable of fully describing an
electron's behavoir? Do you think it is possible that quantumn
mechanics may be replaced by some fine theory which is totally
different in the future?
Replies:
Wentao,
K-space is a model that makes working with quantum mechanics easier.
Whether it is real depends on what you choose to call real. It corresponds
to real properties, but it is not a space that something can move around in.
It is not based on distances.
A wave function describes the STATE of an electron, not its behavior. A
wave funtion can tell you what an electron is capable of doing, but it will
not predict the electron's behavior. In terms of predicting things, the
best a wave function can do is give an EXPECTATION VALUE. Measure the same
quantity for millions of electrons in the same state. The expectation value
corresponds to the average value among all the electrons, not the behavior
of an individual electron.
We do not actually know whether any of physics is exactly correct. We know
what seems to work, and under what conditions. Quantum mechanics may or may
not be correct. Nobody has as of yet come up with anything that works
better than quantum mechanics when working with individual particles.
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