fqe.sparse_hamiltonian.SparseHamiltonian

The Sparse Hamiltonian is characterized by having only one or a few

Inherits From: Hamiltonian

fqe.sparse_hamiltonian.SparseHamiltonian(
    operators: Union[FermionOperator, str],
    conserve_spin: bool = True,
    e_0: complex = (0.0 + 0.0j)
) -> None

elements which are non-zero. This can provide advantages for certain operations where single element access is preferred.

operators Operator with a coefficient in the FermionOperator format.
conserve_spin Whether or not to conserve the Sz symmetry.
e_0 Scalar part of the Hamiltonian.

Methods

calc_diag_transform

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calc_diag_transform() -> np.ndarray

Performs a unitary digaonlizing transformation of the one-body term and returns that transformation.

conserve_number

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conserve_number() -> bool

Returns True if the Hamiltonian is number conserving, else False.

diag_values

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diag_values() -> np.ndarray

Returns the diagonal values packed into a single dimension.

diagonal

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diagonal() -> bool

Returns True if the Hamiltonian is diagonal, else False.

diagonal_coulomb

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diagonal_coulomb() -> bool

Returns True if the Hamiltonian is diagonal coloumb, else False.

dim

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dim()

Dim is the orbital dimension of the Hamiltonian arrays. This function should not be used with SparseHamiltonian

e_0

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e_0()

Returns the scalar potential of the Hamiltonian.

iht

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iht(
    time: float
) -> "SparseHamiltonian"

Return the matrices of the Hamiltonian prepared for time evolution.

Args
time The time step.

is_individual

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is_individual() -> bool

Returns if this Hamiltonian consists of an individual operator plus its Hermitian conjugate.

nterms

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nterms() -> int

Returns the number of non-zero elements in the Hamiltonian.

quadratic

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quadratic() -> bool

Returns True if the Hamiltonian is quadratic, else False.

rank

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rank() -> int

Returns the rank of the largest tensor.

tensors

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tensors() -> Tuple[np.ndarray, ...]

Returns all tensors in order of their rank.

terms

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terms()

Returns the operators that comprise the SparseHamiltonian.

terms_hamiltonian

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terms_hamiltonian() -> List['SparseHamiltonian']

Returns a list of all SparseHamiltonian operator terms.

transform

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transform(
    trans: np.ndarray
) -> np.ndarray

Tranform the one body term using the provided matrix.

Args
trans Unitary transformation.

Returns
Transformed one-body Hamiltonian as a numpy.ndarray.