Hi again,

Sorry if I am spamming you a bit, but I have new informations about my issue :

- my cell hamiltonian is not hermician, but my full hamiltonian is hermician (tested with 'np.allclose(ham, ham.conjugate().transpose())' for both hamiltonians)

- if I put a random magnitude on my second nearest neighbors hopping terms, not a single of these hopping terms remains 'hermician' in my cell hamiltonian, even in the core of the cell (checked by plotting the cell hamiltonian)

   Using real random hopping terms leads to the same result.

I still don't understand why this is happening and how to fix it.

I guess it has something to do with how Kwant construct the hamiltonian depending on the symmetries of the system.

Best regards,

Alexandre