HamiltonianPhaseEstimationResult#

class HamiltonianPhaseEstimationResult(phase_estimation_result, phase_estimation_scale, id_coefficient)[source]#

Bases: AlgorithmResult

Store and manipulate results from running HamiltonianPhaseEstimation.

This API of this class is nearly the same as PhaseEstimatorResult, differing only in the presence of an additional keyword argument in the methods. If scaled is False, then the phases are not translated and scaled to recover the eigenvalues of the Hamiltonian. Instead phi in \([0, 1)\) is returned, as is the case when then unitary is not derived from a Hamiltonian.

This class is meant to be instantiated via HamiltonianPhaseEstimation.estimate.

Parameters:

  • phase_estimation_result (PhaseEstimationResult) – The result object returned by PhaseEstimation.estimate.

  • phase_estimation_scale (PhaseEstimationScale) – object used to scale phases to obtain eigenvalues.

  • id_coefficient (float) – The coefficient of the identity term in the Hamiltonian. Eigenvalues are computed without this term so that the coefficient must added to give correct eigenvalues. This is done automatically when retrieving eigenvalues.

Attributes

most_likely_eigenvalue#

The most likely eigenvalue of the Hamiltonian.

This method calls most_likely_phase and scales the result to obtain an eigenvalue.

Returns:

The most likely eigenvalue of the Hamiltonian.

phase#

The most likely phase of the unitary corresponding to the Hamiltonian.

Returns:

The most likely phase.

Methods

combine(result)#

Any property from the argument that exists in the receiver is updated. :param result: Argument result with properties to be set.

Raises:

TypeError – Argument is None

filter_phases(cutoff=0.0, scaled=True, as_float=True)[source]#

Filter phases as does PhaseEstimatorResult.filter_phases, with the addition that phi is shifted and translated to return eigenvalues of the Hamiltonian.

Parameters:

  • cutoff (float) – Minimum weight of number of counts required to keep a bit string. The default value is 0.0.

  • scaled (bool) – If False, return phi in \([0, 1)\) rather than the eigenvalues of the Hamiltonian.

  • as_float (bool) – If True, returned keys are floats in \([0.0, 1.0)\). If False returned keys are bit strings.

Raises:

ValueError – if as_float is False and scaled is True.

Returns:

A dict of filtered phases.

Return type:

Mapping[str | float, float]