Search found 5 matches

by nervxxx
23 Aug 2020, 18:48
Forum: HowTos and FAQ for TeNPy
Topic: Possible bug to implement vanishing coupling strength?
Replies: 2
Views: 416

Re: Possible bug to implement vanishing coupling strength?

Relatedly, if I try to create a model that has only 2-body couplings but no 1-body terms, a CouplingMPOModel can be created but NearestNeighborModel from NearestNeighborModel.from_MPOMOdel() complains and fails...
by nervxxx
23 Aug 2020, 17:00
Forum: HowTos and FAQ for TeNPy
Topic: Possible bug to implement vanishing coupling strength?
Replies: 2
Views: 416

Possible bug to implement vanishing coupling strength?

I'm trying to produce a model with spatially-dependent on-site terms and was having some difficulty. For example to produce a dimerized pattern of Zeeman fields I use the on-site functionality self.add_onsite(np.array([t1, t2]), 0, 'Sz') If amplitudes t1, t2 are non-zero, everything is fine. I can c...
by nervxxx
20 Aug 2020, 22:48
Forum: HowTos and FAQ for TeNPy
Topic: Bosonic Haldane Model
Replies: 1
Views: 352

Bosonic Haldane Model

I am going through some example models, and was looking at the Bosonic Haldane Model in particular: https://github.com/tenpy/tenpy/blob/master/tenpy/models/haldane.py#L13-L80 It is stated that the Hamiltonian reads .. math :: H = \sum_{ij} t_{ij} b_i^\dagger b_j + \sum_i \mu (n_{A, i} - n_{B, i}) + ...
by nervxxx
20 Aug 2020, 16:53
Forum: HowTos and FAQ for TeNPy
Topic: Qn about iDMRG
Replies: 2
Views: 415

Re: Qn about iDMRG

Thank you for the response. I see, so if I understand correctly what you are saying, there is no way to fix a magnetization density sector at least within iDMRG, even though total magnetization *is* a symmetry of the system and it *is* therefore meaningful to talk about GSes in the different magneti...
by nervxxx
20 Aug 2020, 04:30
Forum: HowTos and FAQ for TeNPy
Topic: Qn about iDMRG
Replies: 2
Views: 415

Qn about iDMRG

Hi, I am new to TeNPY and trying to use it. I tried running the following test script, which is more or less the XXZ example given in the documentation: from tenpy.networks.site import SpinSite from tenpy.models.lattice import Chain from tenpy.models.model import CouplingModel, NearestNeighborModel,...