If it is not much of a problem, can you please clarify some of my questions regarding ITensor library.
(1) The MPS class has
orthogonalize() member function to bring it in right canonized form (except site 1), but the algorithm is unfamiliar. I have searched papers for this algorithm, but couldn't find it. Can you please explain the algorithm? And how is it different from canonization by svd? It is definitely faster than the svd method.
(2) How do I ensure PBC for a MPS ? If I manually create an MPO with first and last term as matrices, and not as row or column vectors, will the
dmrg method result a MPS with PBC? I have checked the code for
sum, but could not find a PBC version of it.
dmrg function is the usual two-site dmrg method. Is there any provision for single-site dmrg?