- #1

QuantumLeak

- 6

- 0

"Ok, I got the point. thanks for replying!

It's just a change of basis that under boundary condition diagonalize the Hamiltonian. But then a subtle point:

In order for k-representation to be a good basis change (i.e. orthogonality and completeness properties) I guess that one has to choose the k values AS if there were periodic boundary conditions (i.e. k=2pi*n/L). Right?

Then another last point:

how do you really model a finite size chain? A finite size chain has zero boundary condition. In this case I use the k representation with k chosen as if there were periodic boundary condition and just then reconstruct the physical wavefunction by making a wavepacket that is zero on the borders?

"