Note

This is the documentation for the current state of the development branch of Qiskit Experiments. The documentation or APIs here can change prior to being released.

HalfAngle

class HalfAngle(physical_qubits, backend=None)

An experiment class to measure the amount by which sx and x are not parallel.

Overview

This experiment runs circuits that repeat blocks of sx - sx - y gates inserted in a Ramsey type experiment, i.e. the full gate sequence is thus Ry(π/2) - [sx - sx - y] ^ n - sx where n is varied.

        ┌─────────┐┌────┐┌────┐┌───┐   ┌────┐┌────┐┌───┐┌────┐ ░ ┌─┐
   q_0: ┤ Ry(π/2) ├┤ sx ├┤ sx ├┤ y ├...┤ sx ├┤ sx ├┤ y ├┤ sx ├─░─┤M├
        └─────────┘└────┘└────┘└───┘   └────┘└────┘└───┘└────┘ ░ └╥┘
meas: 1/════════════════════════════...═══════════════════════════╩═
                                                                  0

This sequence measures angle errors where the axis of the sx and x rotation are not parallel. A similar experiment is described in Ref.~[1] where the gate sequence x - y is repeated to amplify errors caused by non-orthogonal x and y rotation axes. Such errors can occur due to phase errors. For example, the non-linearities in the mixer’s skew for $\pi /2$ pulses may be different from the $\pi$ pulse.

References

[1] Sarah Sheldon, Lev S. Bishop, Easwar Magesan, Stefan Filipp, Jerry M. Chow, Jay M. Gambetta, Characterizing errors on qubit operations via iterative randomized benchmarking, Phys. Rev. A 93, 012301 (2016), doi: 10.1103/PhysRevA.93.012301 (open)

Analysis class reference

ErrorAmplificationAnalysis

Experiment options

These options can be set by the set_experiment_options() method.

Options

• Defined in the class HalfAngle:

  • repetitions (List[int])

    Default value: [0, 1, 2, 3, 4, …]

    A list of the number of times that the gate sequence [sx sx y] is repeated.

• Defined in the class BaseExperiment:

  • max_circuits (Optional[int])

    Default value: None

    The maximum number of circuits per job when running an experiment on a backend.

Initialization

Setup a half angle experiment on the given qubit.

Parameters:

• physical_qubits (Sequence[int]) – List containing the qubits on which to run the fine amplitude calibration experiment.

• backend (Optional[Backend]) – Optional, the backend to run the experiment on.

Attributes

HalfAngle.analysis	Return the analysis instance for the experiment
HalfAngle.backend	Return the backend for the experiment
HalfAngle.experiment_options	Return the options for the experiment.
HalfAngle.experiment_type	Return experiment type.
HalfAngle.num_qubits	Return the number of qubits for the experiment.
HalfAngle.physical_qubits	Return the device qubits for the experiment.
HalfAngle.run_options	Return options values for the experiment run() method.
HalfAngle.transpile_options	Return the transpiler options for the run() method.

Methods

HalfAngle.circuits()	Create the circuits for the half angle calibration experiment.
HalfAngle.config()	Return the config dataclass for this experiment
HalfAngle.copy()	Return a copy of the experiment
HalfAngle.from_config(config)	Initialize an experiment from experiment config
HalfAngle.run([backend, analysis, timeout])	Run an experiment and perform analysis.
HalfAngle.set_experiment_options(**fields)	Set the experiment options.
HalfAngle.set_run_options(**fields)	Set options values for the experiment run() method.
HalfAngle.set_transpile_options(**fields)	Set the transpiler options for run() method.