1.) How to change the model such that it supports toroidal boundary condition, as you suggested in earlier post. Can you guide me for this your famous toric code example.

2.) I tried to implement kitaev model (bond dependent spin interaction) on a honeycomb(default lattice) in tenpy, since I provided the interaction parameter such that spectrum is gapless and corresponding bond dimension is increased correspondingly. I tried providing different order of lattice also, but this does not help. Can changing initial product state helps in this regard?

Is there other possible way to make the problem computationaly easy?

Code: Select all

```
psi = MPS.from_product_state(model.lat.mps_sites(), [1]*(2*Ly*Lx), bc = "infinite")
dmrg_params = {'mixer': True,
'chi_list': {0: 200},
'trunc_params': {'svd_min': 1.e-10},
'verbose': 1}
results = dmrg.run(psi, model, dmrg_params)
```