What is the difference between Phonons and Normal mode? My professor told me that they are the same and that one can get the other from some derivation (I'm a bit unsure if he really said the 'derivation part' because he said more details around that which I did not fully grasp). If it is the case that there is no difference between Phonons and Normal mode then how come there exist two very different words for the same thing?
Below I will make some reference to what I have read that to me makes it seem that there is no difference between Phonons and Normal mode:
"The quanta of lattice vibrations are known as phonons" - Introductory to solid state physics Second Edition by H.P. Myers $\tag{1}$
"A normal mode of an oscillating system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency and with a fixed phase relation." - Wikipedia $\tag{2}$
Related posts:
phonons-and-modes
what-is-the-difference-between-normal-mode-and-just-mode
difference-between-mechanical-modes-and-phonons - this one almost answers my question but then I emphasize on "If it is the case that there is no difference between Phonons and Normal mode then how come there exist two very different words for the same thing?"
