qiskit.aqua.algorithms.IQPE

class IQPE(operator=None, state_in=None, num_time_slices=1, num_iterations=1, expansion_mode='suzuki', expansion_order=2, shallow_circuit_concat=False, quantum_instance=None)

The Iterative Quantum Phase Estimation algorithm.

IQPE, as its name suggests, iteratively computes the phase so as to require fewer qubits. It takes has the same set of parameters as QPE, except for the number of ancillary qubits num_ancillae, being replaced by num_iterations and that an Inverse Quantum Fourier Transform (IQFT) is not used for IQPE.

Reference:

[1]: Dobsicek et al. (2006), Arbitrary accuracy iterative phase estimation algorithm as a two

qubit benchmark, arxiv/quant-ph/0610214

매개변수

• operator (Union[OperatorBase, LegacyBaseOperator, None]) – The hamiltonian Operator

• state_in (Optional[InitialState]) – An InitialState component representing an initial quantum state.

• num_time_slices (int) – The number of time slices, has a minimum value of 1.

• num_iterations (int) – The number of iterations, has a minimum value of 1.

• expansion_mode (str) – The expansion mode (‘trotter’|’suzuki’)

• expansion_order (int) – The suzuki expansion order, has a min. value of 1.

• shallow_circuit_concat (bool) – Set True to use shallow (cheap) mode for circuit concatenation of evolution slices. By default this is False.

• quantum_instance (Union[QuantumInstance, Backend, BaseBackend, None]) – Quantum Instance or Backend

__init__(operator=None, state_in=None, num_time_slices=1, num_iterations=1, expansion_mode='suzuki', expansion_order=2, shallow_circuit_concat=False, quantum_instance=None)

매개변수

• operator (Union[OperatorBase, LegacyBaseOperator, None]) – The hamiltonian Operator

• state_in (Optional[InitialState]) – An InitialState component representing an initial quantum state.

• num_time_slices (int) – The number of time slices, has a minimum value of 1.

• num_iterations (int) – The number of iterations, has a minimum value of 1.

• expansion_mode (str) – The expansion mode (‘trotter’|’suzuki’)

• expansion_order (int) – The suzuki expansion order, has a min. value of 1.

• shallow_circuit_concat (bool) – Set True to use shallow (cheap) mode for circuit concatenation of evolution slices. By default this is False.

• quantum_instance (Union[QuantumInstance, Backend, BaseBackend, None]) – Quantum Instance or Backend

Methods

__init__([operator, state_in, …])	type operator Union[OperatorBase, LegacyBaseOperator, None]
compute_minimum_eigenvalue([operator, …])	Computes minimum eigenvalue.
construct_circuit([k, omega, measurement])	Construct the kth iteration Quantum Phase Estimation circuit.
run([quantum_instance])	Execute the algorithm with selected backend.
set_backend(backend, **kwargs)	Sets backend with configuration.
supports_aux_operators()	Whether computing the expectation value of auxiliary operators is supported.

Attributes

aux_operators	Returns aux operators
backend	Returns backend.
operator	Returns operator
quantum_instance	Returns quantum instance.
random	Return a numpy random.

property aux_operators

Returns aux operators

반환 형식

Optional[List[Union[OperatorBase, LegacyBaseOperator]]]

property backend

Returns backend.

반환 형식

Union[Backend, BaseBackend]

compute_minimum_eigenvalue(operator=None, aux_operators=None)

Computes minimum eigenvalue. Operator and aux_operators can be supplied here and if not None will override any already set into algorithm so it can be reused with different operators. While an operator is required by algorithms, aux_operators are optional. To ‘remove’ a previous aux_operators array use an empty list here.

매개변수

• operator (Union[OperatorBase, LegacyBaseOperator, None]) – If not None replaces operator in algorithm

• aux_operators (Optional[List[Union[OperatorBase, LegacyBaseOperator]]]) – If not None replaces aux_operators in algorithm

반환 형식

MinimumEigensolverResult

반환값

MinimumEigensolverResult

construct_circuit(k=None, omega=0, measurement=False)

Construct the kth iteration Quantum Phase Estimation circuit.

For details of parameters, please see Fig. 2 in https://arxiv.org/pdf/quant-ph/0610214.pdf.

매개변수

• k (Optional[int]) – the iteration idx.

• omega (float) – the feedback angle.

• measurement (bool) – Boolean flag to indicate if measurement should be included in the circuit.

반환값

the quantum circuit per iteration

반환 형식

QuantumCircuit

property operator

Returns operator

반환 형식

Union[OperatorBase, LegacyBaseOperator, None]

property quantum_instance

Returns quantum instance.

반환 형식

Optional[QuantumInstance]

property random

Return a numpy random.

run(quantum_instance=None, **kwargs)

Execute the algorithm with selected backend.

매개변수

• quantum_instance (Union[QuantumInstance, Backend, BaseBackend, None]) – the experimental setting.

• kwargs (dict) – kwargs

반환값

results of an algorithm.

반환 형식

dict

예외

AquaError – If a quantum instance or backend has not been provided

set_backend(backend, **kwargs)

Sets backend with configuration.

반환 형식

None

classmethod supports_aux_operators()

Whether computing the expectation value of auxiliary operators is supported.

If the minimum eigensolver computes an eigenstate of the main operator then it can compute the expectation value of the aux_operators for that state. Otherwise they will be ignored.

반환 형식

bool

반환값

True if aux_operator expectations can be evaluated, False otherwise