Return the external potential in the dual basis of arXiv:1706.00023.
openfermion.hamiltonians.dual_basis_external_potential(
grid: openfermion.utils.Grid
,
geometry: List[Tuple[str, Tuple[Union[int, float], Union[int, float], Union[int, float]]]
],
spinless: bool,
non_periodic: bool = False,
period_cutoff: Optional[float] = None
) -> openfermion.ops.FermionOperator
The external potential resulting from electrons interacting with nuclei
in the plane wave dual basis. Note that a cos term is used which is
strictly only equivalent under aliasing in odd grids, and amounts
to the addition of an extra term to make the diagonals real on even
grids. This approximation is not expected to be significant and allows
for use of even and odd grids on an even footing.
Args |
grid (Grid): The discretization to use.
|
geometry
|
A list of tuples giving the coordinates of each atom.
example is [('H', (0, 0, 0)), ('H', (0, 0, 0.7414))].
Distances in atomic units. Use atomic symbols to specify atoms.
spinless (bool): Whether to use the spinless model or not.
non_periodic (bool): If the system is non-periodic, default to False.
period_cutoff (float): Period cutoff, default to
grid.volume_scale() ** (1. / grid.dimensions)
|
Returns |
FermionOperator
|
The dual basis operator.
|