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.

FineFrequency

class FineFrequency(physical_qubits, delay_duration, backend=None, repetitions=None)[source]

An experiment to make a fine measurement of the qubit frequency.

Overview

The fine frequency characterization experiment measures the qubit frequency by moving to the equator of the Bloch sphere with a sx gate and idling for a time \(n\cdot \tau\) where \(\tau\) is the duration of the single-qubit gate and \(n\) is an integer which ranges from zero to a maximal value in integer steps. The idle time is followed by a rz rotation with an angle \(n\pi/2\) and a final sx gate. If the frequency of the pulses match the frequency of the qubit then the sequence \(n\in[0,1,2,3,4,...]\) will result in the sequence of measured qubit populations \([1, 0.5, 0, 0.5, 1, ...]\) due to the rz rotation. If the frequency of the pulses do not match the qubit frequency then the qubit will precess in the drive frame during the idle time and phase errors will build-up. By fitting the measured points we can extract the error in the qubit frequency. The circuit that are run are

        ┌────┐┌────────────────┐┌──────────┐┌────┐ ░ ┌─┐
     q: ┤ √X ├┤ Delay(n*τ[dt]) ├┤ Rz(nπ/2) ├┤ √X ├─░─┤M├
        └────┘└────────────────┘└──────────┘└────┘ ░ └╥┘
meas: 1/══════════════════════════════════════════════╩═
                                                      0

Analysis class reference

ErrorAmplificationAnalysis

Experiment options

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

Options

  • Defined in the class FineFrequency:

    • repetitions (List[int])

      Default value: [0, 1, 2, 3, 4, …]
      A list of the number of times that the delay is repeated.

    • delay_duration (int)

      Default value: None
      The duration of the delay as the number of dt s it contains. The total length of the delay in units of dt will be n times delay_duration where n also determines the rotation angle of the RZGate by \(n \pi/2\).

  • 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.

Example

from qiskit_experiments.library.characterization import FineFrequency

repetitions = list(range(40))

exp = FineFrequency((0,),
                    delay_duration=320,
                    backend=backend,
                    repetitions=repetitions)
exp.set_transpile_options(optimization_level=0, basis_gates=['sx', 'rz', 'delay'])

exp_data = exp.run().block_for_results()
display(exp_data.figure(0))
exp_data.analysis_results(dataframe=True)
../_images/qiskit_experiments.library.characterization.FineFrequency_1_0.png
name experiment components value quality backend run_time chisq
fc6344ff @Parameters_ErrorAmplificationAnalysis FineFrequency [Q0] CurveFitResult:\n - fitting method: least_squa... good aer_simulator_from(fake_perth) None None
fdb7131d d_theta FineFrequency [Q0] -0.00063+/-0.00032 good aer_simulator_from(fake_perth) None 1.299274

Initialization

Setup a fine frequency experiment on the given qubit.

Parameters:

  • physical_qubits (Sequence[int]) – List containing the qubit on which to run the fine frequency characterization experiment.

  • delay_duration (int) – The duration of the delay at \(n=1\) in dt.

  • backend (Backend | None) – Optional, the backend to run the experiment on.

  • repetitions (List[int] | None) – The number of repetitions, if not given then the default value from the experiment default options will be used.

Attributes

analysis

Return the analysis instance for the experiment

backend

Return the backend for the experiment

experiment_options

Return the options for the experiment.

experiment_type

Return experiment type.

num_qubits

Return the number of qubits for the experiment.

physical_qubits

Return the device qubits for the experiment.

run_options

Return options values for the experiment run() method.

transpile_options

Return the transpiler options for the run() method.

Methods

circuits()[source]

Return the list of quantum circuits to run.

Return type:

List[QuantumCircuit]

config()

Return the config dataclass for this experiment

Return type:

ExperimentConfig

copy()

Return a copy of the experiment

Return type:

BaseExperiment

classmethod from_config(config)

Initialize an experiment from experiment config

Return type:

BaseExperiment

job_info(backend=None)

Get information about job distribution for the experiment on a specific backend.

Parameters:

backend (Backend) – Optional, the backend for which to get job distribution information. If not specified, the experiment must already have a set backend.

Returns:

A dictionary containing information about job distribution.

  • ”Total number of circuits in the experiment”: Total number of circuits in the experiment.

  • ”Maximum number of circuits per job”: Maximum number of circuits in one job based on backend and experiment settings.

  • ”Total number of jobs”: Number of jobs needed to run this experiment on the currently set backend.

Return type:

dict

Raises:

QiskitError – if backend is not specified.

run(backend=None, sampler=None, analysis='default', timeout=None, backend_run=None, **run_options)

Run an experiment and perform analysis.

Parameters:

  • backend (Backend | None) – Optional, the backend to run on. Will override existing backend settings.

  • sampler (BaseSamplerV2 | None) – Optional, the sampler to run the experiment on. If None then a sampler will be invoked from previously set backend

  • analysis (BaseAnalysis | None) – Optional, a custom analysis instance to use for performing analysis. If None analysis will not be run. If "default" the experiments analysis() instance will be used if it contains one.

  • timeout (float | None) – Time to wait for experiment jobs to finish running before cancelling.

  • backend_run (bool | None) – Use backend run (temp option for testing)

  • run_options – backend runtime options used for circuit execution.

Returns:

The experiment data object.

Raises:

QiskitError – If experiment is run with an incompatible existing ExperimentData container.

Return type:

ExperimentData

set_experiment_options(**fields)

Set the experiment options.

Parameters:

fields – The fields to update the options

Raises:

AttributeError – If the field passed in is not a supported options

set_run_options(**fields)

Set options values for the experiment run() method.

Parameters:

fields – The fields to update the options

See also

The Setting options for your experiment guide for code example.

set_transpile_options(**fields)

Set the transpiler options for run() method.

Parameters:

fields – The fields to update the options

Raises:

QiskitError – If initial_layout is one of the fields.

See also

The Setting options for your experiment guide for code example.