openfermion.circuits.TrotterStep

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A method for performing a Trotter step.

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Main aliases

openfermion.TrotterStep, openfermion.circuits.trotter.TrotterStep, openfermion.circuits.trotter.trotter_algorithm.TrotterStep

openfermion.circuits.TrotterStep(
    hamiltonian: openfermion.circuits.trotter.trotter_algorithm.Hamiltonian
) -> None

This class assumes that Hamiltonian evolution using a Trotter-Suzuki product formula is performed in the following steps:

1. Perform some preparatory operations (for instance, a basis change).
2. Perform a number of Trotter steps. Each Trotter step may induce a
   permutation on the ordering in which qubits represent fermionic
   modes.
3. Perform some finishing operations.

Attributes
hamiltonian	The Hamiltonian being simulated.

Methods

finish

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finish(
    qubits: Sequence[cirq.Qid],
    n_steps: int,
    control_qubit: Optional[cirq.Qid] = None,
    omit_final_swaps: bool = False
) -> cirq.OP_TREE

Operations to perform after all Trotter steps are done.

Args
qubits	The qubits on which to perform operations.
hamiltonian	The Hamiltonian to simulate.
n_steps	The total number of Trotter steps that have been performed.
control_qubit	The control qubit, if the algorithm is controlled.
omit_final_swaps	Whether or not to omit swap gates at the end of the circuit.

prepare

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prepare(
    qubits: Sequence[cirq.Qid], control_qubit: Optional[cirq.Qid] = None
) -> cirq.OP_TREE

Operations to perform before doing the Trotter steps.

Args
qubits	The qubits on which to perform operations. They should be sorted so that the j-th qubit in the Sequence holds the occupation of the j-th fermionic mode.
hamiltonian	The Hamiltonian to simulate.
control_qubit	The control qubit, if the algorithm is controlled.

step_qubit_permutation

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step_qubit_permutation(
    qubits: Sequence[cirq.Qid], control_qubit: Optional[cirq.Qid] = None
) -> Tuple[Sequence[cirq.Qid], Optional[cirq.Qid]]

The qubit permutation induced by a single Trotter step.

Returns
A tuple whose first element is the new list of system qubits and second element is the new control qubit

trotter_step

View source

@abc.abstractmethod
trotter_step(
    qubits: Sequence[cirq.Qid],
    time: float,
    control_qubit: Optional[cirq.Qid] = None
) -> cirq.OP_TREE

Yield operations to perform a Trotter step.

Args
qubits	The qubits on which to apply the Trotter step.
hamiltonian	The Hamiltonian to simulate.
time	The evolution time.
control_qubit	The control qubit, if the algorithm is controlled.