qml.spin.spin_hamiltonian

spin_hamiltonian(lattice)

Generates a spin Hamiltonian for a custom Lattice object.

Parameters

lattice (Lattice) – custom lattice defined with custom_edges

Raises

ValueError – if the provided Lattice does not have custom_edges defined with operators

Returns

Hamiltonian for the lattice

Return type

Sum

Example

>>> lattice = qml.spin.Lattice(
...     n_cells=[2, 2],
...     vectors=[[1, 0], [0, 1]],
...     positions=[[0, 0], [1, 5]],
...     boundary_condition=False,
...     custom_edges=[[(0, 1), ("XX", 0.5)], [(1, 2), ("YY", 0.6)], [(1, 4), ("ZZ", 0.7)]],
...     custom_nodes=[[0, ("X", 0.5)], [1, ("Y", 0.3)]],
... )
>>> qml.spin.spin_hamiltonian(lattice=lattice)
(
    0.5 * (X(0) @ X(1))
  + 0.5 * (X(2) @ X(3))
  + 0.5 * (X(4) @ X(5))
  + 0.5 * (X(6) @ X(7))
  + 0.6 * (Y(1) @ Y(2))
  + 0.6 * (Y(5) @ Y(6))
  + 0.7 * (Z(1) @ Z(4))
  + 0.7 * (Z(3) @ Z(6))
  + 0.5 * X(0)
  + 0.3 * Y(1)
)

code/api/pennylane.spin.spin_hamiltonian

 

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