Dear ALPS friends,
I'm trying to generate Hamiltonian matrix elements for lattice models using the kitchen sink of symmetries in ALPS. Unfortunately, I can't figure out where I can get them by reading the source code.
Specifically, I'm looking for the quantity M(i,j,k,l) which defines the Hamiltonian H = sum(i,j,k,l) M(i,j,k,l) c(i)+ c(j)+ c(l) c(k). I doubt it is ever stored complete in memory, but I just want to read it out element-by-element in sparse format into an external file. If no part of this quantity ever exists but can be obtained by some modifying the code, that works, too.
If someone can point me to the right place and make a suggestion for what to do, that would be fantastic. If this is not a simple request at all, but someone still wants to help me, I can give a much more detailed explanation of what I'm trying to do.
Jeff Hammond The University of Chicago