full name: tenpy.models.spins_nnn
Spin-S sites coupled by (next-)nearest neighbor interactions on a GroupedSite.
Spin-S sites coupled by next-nearest neighbor interactions.
Next-Nearest-neighbor spin-S models.
Uniform lattice of spin-S sites, coupled by next-nearest-neighbor interactions.
We have two variants implementing the same hamiltonian.
SpinChainNNN uses the
GroupedSite to keep it a
NearestNeighborModel suitable for TEBD,
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.