spins_nnn¶
full name: tenpy.models.spins_nnn
parent module:
tenpy.models
type: module
Classes

|
Spin-S sites coupled by (next-)nearest neighbour interactions on a GroupedSite. |
|
Spin-S sites coupled by next-nearest neighbour interactions. |
Module description
Next-Nearest-neighbour spin-S models.
Uniform lattice of spin-S sites, coupled by next-nearest-neighbour interactions.
We have two variants implementing the same hamiltonian.
The SpinChainNNN
uses the
GroupedSite
to keep it a
NearestNeighborModel
suitable for TEBD,
while the SpinChainNNN2
just involves longer-range couplings in the MPO.
The latter is preferable for pure DMRG calculations and avoids having to add each of the short
range couplings twice for the grouped sites.
Note that you can also get a NearestNeighborModel
for TEBD from the
latter by using group_sites()
and
from_MPOModel()
.
An example for such a case is given in the file examples/c_tebd.py
.