Search found 3 matches

by aeberharter
08 Feb 2022, 11:50
Forum: HowTos and FAQ for TeNPy
Topic: How to convert iMPS to finite MPS?
Replies: 2
Views: 11737

How to convert iMPS to finite MPS?

I have an iMPS as the result of an iDMRG run. By calling

Code: Select all

psi.enlarge_mps_unit_cell(m)
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?
by aeberharter
31 Mar 2020, 11:14
Forum: HowTos and FAQ for TeNPy
Topic: Excited states of effective Hamiltonian
Replies: 1
Views: 3410

Excited states of effective Hamiltonian

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 ...
by aeberharter
06 Nov 2019, 13:12
Forum: Algorithms
Topic: Canonical form for very small singular values
Replies: 1
Views: 8696

Canonical form for very small singular values

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 ...