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intrcmap_kagome

Generate an interaction map for a 2D Kagome lattice.

Call build_geometry(geo_cfg) to construct a Geometry, then pass it here. The TOML keys below are the fields that belong in the [geometry] section.

intrcmap_kagome 

intrcmap_kagome(geo: Geometry) -> List[Interaction2Site]

Generate an interaction map for a Kagome lattice.

Produces nearest-neighbor (NN) interactions within each upward triangle (N2U) and between unit cells via three downward-triangle bond families (N2D). Coupling constants are not set here; all returned interactions have cpl == 0.0.

Labels encode bond topology:

  • ['NN', 'N2U'] — upward-triangle bonds (A–B, A–C, B–C within a cell).
  • ['NN', 'N2D'] — downward-triangle bonds (bonds 4, 5, 6 between cells).
  • PBC bonds additionally carry 'PBC' in the label list.

Parameters:

Name Type Description Default
geo Geometry

Fully-resolved geometry struct for the Kagome lattice. Relevant config keys (read from geo.cfg):

  • bcx — boundary condition along x ('OBC' or 'PBC').
  • bcy — boundary condition along y ('OBC' or 'PBC').
  • n2u — include N2U (upward-triangle) bonds (default True).
  • n2d — include N2D (downward-triangle) bonds (default True).
 required

Returns:

Type Description
List[Interaction2Site]

Interaction objects sorted by leading_site. Tensor fields are None; cpl is 0.0.

TOML Keys

Key Type Default Description
lx int required Number of unit-cell columns
ly int required Number of unit-cell rows
bcx str "OBC" Boundary condition along x
bcy str "OBC" Boundary condition along y
n2u bool true Include N2U (upward-triangle) bonds
n2d bool true Include N2D (downward-triangle) bonds

The total number of MPS sites is lx * ly * 3 (three sublattice sites A, B, C per unit cell).

Traversal Order (traverse)

Value Ordering
"sequential" column-major, same direction every column (default)
"serpentine" column-major, alternating direction

Bond Labels

Label Bond family
['NN', 'N2U'] Upward-triangle NN bond (A–B, A–C, B–C within a unit cell)
['NN', 'N2D'] Downward-triangle NN bond (between adjacent unit cells)
['NN', 'N2U', 'PBC'] N2U bond closing a periodic boundary
['NN', 'N2D', 'PBC'] N2D bond closing a periodic boundary

See Also