Coupled Ladders

Dense (PyTorch)

This implementation of SU(2)-symmetric model of coupled spin-1/2 ladders on square lattice does not assume any symmetry and works with dense PyTorch tensors.

Dense (YAST)

This implementation of SU(2)-symmetric model of coupled spin-1/2 ladders works with dense YAST tensors. In particular, the physical reduced density matrices, Hamiltonian terms, observables, etc. are dense YAST tensors. As such, their indices have signature.

Note

The underlying iPEPS wavefunction can make use of explicit internal symmetry and thus block-sparse tensors. After physical reduced density matrices are built from such iPEPS and its environment, they are converted to dense form (keeping signature information).

With explict U(1) symmetry

This implementation of SU(2)-symmetric model of coupled spin-1/2 ladders works with explicit U(1) abelian symmetry (subgroup). The physical reduced density matrices, Hamiltonian terms, observables, etc. have U(1) block-sparse structure.