Hi all(adsbygoogle = window.adsbygoogle || []).push({});

I have a question regarding Bloch's theorem (also known as Floquet's theorem) and its use. I have seen in many solid state textbooks the famous problem of N coupled oscillators where one finds the dispersion relation analytically by using Bloch's theorem. However many times, authors add the comment that N tends to infinity.

My question is:

Is it "right" to use Bloch's theorem forfinite,periodicstructures ?

By "right" i mean if it is physically correct - not if one can do that as an approximation.

To my understanding (so far) Bloch's theorem has also to do with the boundary conditions (right?). In a finite structure there would be a problem at the endpoints unless the boundary conditions are cyclic. Then the theorem works, but can one do the same in a more general case without cyclic boundary conditions ?

Thanks

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# Bloch's theorem for finite systems ?

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