Convert a quadratic fermionic operator to QuadraticHamiltonian.
openfermion.transforms.get_quadratic_hamiltonian(
fermion_operator,
chemical_potential=0.0,
n_qubits=None,
ignore_incompatible_terms=False
)
Used in the notebooks
Args |
fermion_operator(FermionOperator): The operator to convert.
chemical_potential(float): A chemical potential to include in
the returned operator
n_qubits(int): Optionally specify the total number of qubits in the
system
ignore_incompatible_terms(bool): This flag determines the behavior
of this method when it encounters terms that are not quadratic
that is, terms that are not of the form a^\dagger_p a_q.
If set to True, this method will simply ignore those terms.
If False, then this method will raise an error if it encounters
such a term. The default setting is False.
|
Returns |
quadratic_hamiltonian
|
An instance of the QuadraticHamiltonian class.
|
Raises |
TypeError
|
Input must be a FermionOperator.
|
TypeError
|
FermionOperator does not map to QuadraticHamiltonian.
|
Warning |
Even assuming that each creation or annihilation operator appears
at most a constant number of times in the original operator, the
runtime of this method is exponential in the number of qubits.
|