Hi again, I am afraid that what you are specifically asking is still not clear to me.
> > Thank you for your reply. As for my second question I think I need > state it again. I meant to tell that how we get the probability > density distribution: > > sys=sys.finalized() > ham=sys.hamiltonian_submatrix(args=[Zeeman]) > eval,evec=la.eigh(ham) > vec1=evec[:,L] > vec2=evec[:,L-1] > dv1=np.sqrt(1/2)*(vec1+vec2) > dv2=np.sqrt(1/2)*(vec1-vec2) 'vec1' and 'vec2' are normalized eigenvectors of 'ham'. The individual components, e.g. 'vec1[10]' are probability amplitudes for the different degrees of freedom in your system, that you defined (implicitly) when you constructed the Hamiltonian. 'vec1[10]', for example refers to the degree of freedom "number '10'" when the system is in a state 'vec1'. Now the question is "what is degree of freedom does the label '10'" refer to? You built your system by assigning onsite values to different sites and hoppings in between them. When you finalize your system, Kwant internally orders the sites and their associated degrees of freedom in some manner, and this ordering is what the number "10" refers to in the preceding paragraph. In general Kwant groups degrees of freedom on the same site together, and the sites are ordered in an arbitrary fashion. You can find the ordering of sites by inspecting the 'sites' attribute of a finalized system. Given that your example contains a variable called 'Zeeman', I am going to assume that you have a system made of sites that have exactly 2 (spin) degrees of freedom each (the onsites and hoppings are 2x2 matrices), ordered like (spin up, spin down). As there are exactly 2 degrees of freedom per site we know that all the degrees of freedom with even numbers are spin up, and all the degrees of freedom with odd numbers are spin down. The site index can be found by doing an integer division by 2 of the index of the degree of freedom. So degree of freedom "10" corresponds to spin up on site 'system.sites[5]'. Hope that helps, Joe
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