This question is basically the same as this: https://email@example.com/msg00076.html
I want to calculate some things using the scattering matrix. I started out with a very simple system, most basic two-terminal system. For some energy there is one propagating mode. I now add matrix structure to the mix (just multiply by s_0 everywhere) and there are now 2 propagating modes (which makes sense).
Now, if I look at the reflection coefficients for lead 0 by using submatrix(0,0), it is now a 2x2 matrix after I introduced the matrices. How are the elements ordered? Is it
[[r_upup, r_updown],[r_downup, r_downdown]]
I know that I could make two lattices, but since I do not plan to use the other functions such as transmission. I just want the smatrix.
Hope you can help me, and thanks in advance.