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.

InterleavedRB

class InterleavedRB(interleaved_element, physical_qubits, lengths, backend=None, num_samples=3, seed=None, full_sampling=False, circuit_order='RIRIRI')

An experiment to characterize the error rate of a specific gate on a device.

Overview

Interleaved Randomized Benchmarking (RB) is a method to estimate the average error-rate of a certain quantum gate.

An interleaved RB experiment generates a standard RB sequences of random Cliffords and another sequence with the interleaved given gate. After running the two sequences on a backend, it calculates the probabilities to get back to the ground state, fits the two exponentially decaying curves, and estimates the interleaved gate error. See Ref. [1] for details.

References

[1] Easwar Magesan, Jay M. Gambetta, B. R. Johnson, Colm A. Ryan, Jerry M. Chow, Seth T. Merkel, Marcus P. da Silva, George A. Keefe, Mary B. Rothwell, Thomas A. Ohki, Mark B. Ketchen, M. Steffen, Efficient measurement of quantum gate error by interleaved randomized benchmarking, Phys. Rev. Lett. 109, 080505 (2012), doi: 10.1103/PhysRevLett.109.080505 (open)

User manual

Randomized Benchmarking

Analysis class reference

InterleavedRBAnalysis

Experiment options

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

Options

• Defined in the class InterleavedRB:

  • circuit_order (str)

    Default value: "RIRIRI"

    How to order the reference and the interleaved circuits. "RIRIRI" (alternate a reference and an interleaved circuit) or "RRRIII" (push all reference circuits first, then all interleaved ones).

• Defined in the class StandardRB:

  • lengths (List[int])

    Default value: None

    A list of RB sequences lengths.

  • num_samples (int)

    Default value: None

    Number of samples to generate for each sequence length.

  • seed (None or int or SeedSequence or BitGenerator or Generator)

    Default value: None

    A seed used to initialize numpy.random.default_rng when generating circuits. The default_rng will be initialized with this seed value every time circuits() is called.

  • full_sampling (bool)

    Default value: None

    If True all Cliffords are independently sampled for all lengths. If False for sample of lengths longer sequences are constructed by appending additional Clifford samples to shorter sequences.

  • clifford_synthesis_method (str)

    Default value: "rb_default"

    The name of the Clifford synthesis plugin to use for building circuits of RB sequences.

• 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.

See also

• Superclass qiskit_experiments.library.randomized_benchmarking.standard_rb.StandardRB

Initialization

Initialize an interleaved randomized benchmarking experiment.

Parameters:

• interleaved_element (QuantumCircuit | Gate | Delay | Clifford) – The element to interleave, given either as a Clifford element, gate, delay or circuit. All instructions in the element must be supported in the backend``(``target). If it is/contains a delay, its duration and unit must comply with the timing constraints of the backend (BackendTiming is useful to obtain valid delays). Parameterized circuits/instructions are not allowed.

• physical_qubits (Sequence[int]) – list of physical qubits for the experiment.

• lengths (Iterable[int]) – A list of RB sequences lengths.

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

• num_samples (int) – Number of samples to generate for each sequence length.

• seed (int | SeedSequence | BitGenerator | Generator | None) – Optional, seed used to initialize numpy.random.default_rng. when generating circuits. The default_rng will be initialized with this seed value every time circuits() is called.

• full_sampling (bool) – If True all Cliffords are independently sampled for all lengths. If False for sample of lengths longer sequences are constructed by appending additional Clifford samples to shorter sequences.

• circuit_order (str) – How to order the reference and the interleaved circuits. "RIRIRI" (default) - Alternate a reference and an interleaved circuit. Or "RRRIII" - Push all reference circuits first, then all interleaved ones.

Raises:

• QiskitError – When interleaved_element has different number of qubits from the physical_qubits argument.

• QiskitError – When interleaved_element is not convertible to Clifford object.

• QiskitError – When interleaved_element has an invalid delay (e.g. violating the timing constraints of the backend).

Attributes

analysis: BaseAnalysis

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()

Return a list of RB circuits.

Returns:

A list of QuantumCircuit.

Raises:

QiskitError – If interleaved_element has non-supported instruction in the backend.

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

enable_restless(rep_delay=None, override_processor_by_restless=True, suppress_t1_error=False)

Enables a restless experiment by setting the restless run options and the restless data processor.

Deprecated since version 0.8: The method qiskit_experiments.framework.restless_mixin.RestlessMixin.enable_restless() is deprecated as of qiskit-experiments 0.8. It will be removed no earlier than 3 months after the release date. Support for restless experiments has been deprecated.

Parameters:

• rep_delay (float | None) – The repetition delay. This is the delay between a measurement and the subsequent quantum circuit. Since the backends have dynamic repetition rates, the repetition delay can be set to a small value which is required for restless experiments. Typical values are 1 us or less.

• override_processor_by_restless (bool) – If False, a data processor that is specified in the analysis options of the experiment is not overridden by the restless data processor. The default is True.

• suppress_t1_error (bool) – If True, the default is False, then no error will be raised when rep_delay is larger than the T1 times of the qubits. Instead, a warning will be logged as restless measurements may have a large amount of noise.

Raises:

• DataProcessorError – If the attribute rep_delay_range is not defined for the backend.

• DataProcessorError – If a data processor has already been set but override_processor_by_restless is True.

• DataProcessorError – If the experiment analysis does not have the data_processor option.

• DataProcessorError – If the rep_delay is equal to or greater than the T1 time of one of the physical qubits in the experiment and the flag ignore_t1_check is False.

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.