I can easily increase the number of sites in the unit cell, however it is still in iMPS form.
Would it work if one calculates the canonical_form with setting the bond dimension to chi = 1 at the boundary?
I have an already converged infinite system (iMPS). Now I want to obtain the first 5 excited energies (states do not really matter) of the effective Hamiltonian of the converged system. What I did so far is: def lanczos_arpack_spectrum(H, psi, k, lanczos_params={}): """ <Removed docs ...
The present algorithm to calculate the canonical form for infinite systems calculates the left and right dominant eigenvectors and takes the square root of each, which comes with a loss in precision. It turns out that close to criticality and at large bond dimensions singular values eventually will ...