Hi everyone! I am a beginner Kwant consumer and, for this reason, I am trying to "solve" very simple problems, i.e. problems for beginners. The first one is the following: I have a 1D problem where basically a spin-1/2 particle crosses a region without a potential neither magnetic fields. I am able to write correctly the setup of the problem in Kwant. Fixed the incoming particle energy, I find a 4 by 4 scattering matrix (this is comforting), but I do not understand which is the protocol that Kwant uses to order the coefficients in the scattering matrix. For example, according to the usual description of the transmission matrix (from left-to-right), the element t_{00} corresponding to the probability to start, for example, in the state s=-1/2 in the left lead and arrives in the state s=-1/2 in the right lead, and similarly for the other elements. How can I manage these labeling in my code? Thank you!