Hi,
Im a bit confused on the names used in the lecture notes, the term “momenta” or “moment” are in de debye notes only mentioned in the learning goals and later the question.
What is this momenta exactly ?
“Momenta” is a plural of “momentum”. In quantum mechanics, momentum of a wave p is related to its wave vector k through the relation of p = \hbar k. This relation is so universal that the terms “momentum” and “wave vector” are often used interchangeably.
This correspondence, however, should be properly introduced (we discuss this in more detail when talking about electrons), and therefore I’ve replaced these occurrences of “momenta” with “wave vectors”.
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