IBMBackend

class IBMBackend(configuration, service, api_client, instance=None, calibration_id=None)[source]

Bases: BackendV2

Backend class interfacing with an IBM Quantum backend.

Note

  • You should not instantiate the IBMBackend class directly. Instead, use the methods provided by an QiskitRuntimeService instance to retrieve and handle backends.

This class represents an IBM Quantum backend. Its attributes and methods provide information about the backend. For example, the status() method returns a BackendStatus instance. The instance contains the operational and pending_jobs attributes, which state whether the backend is operational and also the number of jobs in the server queue for the backend, respectively:

status = backend.status()
is_operational = status.operational
jobs_in_queue = status.pending_jobs

Here is list of attributes available on the IBMBackend class:

  • name: backend name.

  • backend_version: backend version in the form X.Y.Z.

  • num_qubits: number of qubits.

  • target: A qiskit.transpiler.Target object for the backend.

  • basis_gates: list of basis gates names on the backend.

  • gates: list of basis gates on the backend.

  • local: backend is local or remote.

  • simulator: backend is a simulator.

  • conditional: backend supports conditional operations.

  • open_pulse: backend supports open pulse.

  • memory: backend supports memory.

  • coupling_map (list): The coupling map for the device

  • supported_instructions (List[str]): Instructions supported by the backend.

  • dynamic_reprate_enabled (bool): whether delay between primitives can be set dynamically (ie via rep_delay). Defaults to False.

  • rep_delay_range (List[float]): 2d list defining supported range of repetition delays for backend in μs. First entry is lower end of the range, second entry is higher end of the range. Optional, but will be specified when dynamic_reprate_enabled=True.

  • default_rep_delay (float): Value of rep_delay if not specified by user and dynamic_reprate_enabled=True.

  • n_uchannels: Number of u-channels.

  • u_channel_lo: U-channel relationship on device los.

  • meas_levels: Supported measurement levels.

  • qubit_lo_range: Qubit lo ranges for each qubit with form (min, max) in GHz.

  • meas_lo_range: Measurement lo ranges for each qubit with form (min, max) in GHz.

  • dt: Qubit drive channel timestep in nanoseconds.

  • dtm: Measurement drive channel timestep in nanoseconds.

  • rep_times: Supported repetition times (program execution time) for backend in μs.

  • meas_kernels: Supported measurement kernels.

  • discriminators: Supported discriminators.

  • hamiltonian: An optional dictionary with fields characterizing the system hamiltonian.

  • channel_bandwidth (list): Bandwidth of all channels (qubit, measurement, and U)

  • acquisition_latency (list): Array of dimension n_qubits x n_registers. Latency (in units of dt) to write a measurement result from qubit n into register slot m.

  • conditional_latency (list): Array of dimension n_channels [d->u->m] x n_registers. Latency (in units of dt) to do a conditional operation on channel n from register slot m

  • meas_map (list): Grouping of measurement which are multiplexed

  • sample_name (str): Sample name for the backend

  • n_registers (int): Number of register slots available for feedback (if conditional is True)

  • register_map (list): An array of dimension n_qubits X n_registers that specifies whether a qubit can store a measurement in a certain register slot.

  • configurable (bool): True if the backend is configurable, if the backend is a simulator

  • credits_required (bool): True if backend requires credits to run a job.

  • online_date (datetime): The date that the device went online

  • display_name (str): Alternate name field for the backend

  • description (str): A description for the backend

  • tags (list): A list of string tags to describe the backend

  • version: version of Backend class (Ex: 1, 2)

  • channels: An optional dictionary containing information of each channel – their purpose, type, and qubits operated on.

  • parametric_pulses (list): A list of pulse shapes which are supported on the backend. For example: ['gaussian', 'constant']

  • processor_type (dict): Processor type for this backend. A dictionary of the form {"family": <str>, "revision": <str>, segment: <str>} such as {"family": "Canary", "revision": "1.0", segment: "A"}.

    • family: Processor family of this backend.

    • revision: Revision version of this processor.

    • segment: Segment this processor belongs to within a larger chip.

IBMBackend constructor.

Parameters:

  • configuration (QasmBackendConfiguration) – Backend configuration.

  • service (qiskit_runtime_service.QiskitRuntimeService) – Instance of QiskitRuntimeService.

  • api_client (RuntimeClient) – IBM client used to communicate with the server.

  • calibration_id (Optional[str]) – An optional calibration id to use for this backend

  • instance (Optional[str])

Attributes

calibration_id

The calibration id used for this backend.

coupling_map

Return the CouplingMap object

dt

Return the system time resolution of input signals

This is required to be implemented if the backend supports Pulse scheduling.

Returns:

The input signal timestep in seconds. If the backend doesn’t define dt, None will be returned.

dtm

Return the system time resolution of output signals

Returns:

The output signal timestep in seconds.

Return type:

dtm

id_warning_issued = False
instruction_durations

Return the InstructionDurations object.

instructions

A list of Instruction tuples on the backend of the form (instruction, (qubits)

max_circuits

This property used to return the max_experiments value from the backend configuration but this value is no longer an accurate representation of backend circuit limits. New fields will be added to indicate new limits.

meas_map

Return the grouping of measurements which are multiplexed

This is required to be implemented if the backend supports Pulse scheduling.

Returns:

The grouping of measurements which are multiplexed

Return type:

meas_map

num_qubits

Return the number of qubits the backend has.

operation_names

A list of instruction names that the backend supports.

operations

A list of Instruction instances that the backend supports.

options

Return the options for the backend

The options of a backend are the dynamic parameters defining how the backend is used. These are used to control the run() method.

provider

Return the backend provider.

Returns:

the provider responsible for the backend.

Return type:

provider

service

Return the service object

Returns:

instance of QiskitRuntimeService

Return type:

service

target

A qiskit.transpiler.Target object for the backend.

Returns:

Target

version = 2
name

Name of the backend.

description

Optional human-readable description.

online_date

Date that the backend came online.

backend_version

Version of the backend being provided. This is not the same as BackendV2.version, which is the version of the Backend abstract interface.

Methods

__call__()[source]

Call self as a function.

Return type:

IBMBackend

check_faulty(circuit)[source]

Check if the input circuit uses faulty qubits or edges.

Parameters:

circuit (QuantumCircuit) – Circuit to check.

Raises:

ValueError – If an instruction operating on a faulty qubit or edge is found.

Return type:

None

configuration()[source]

Return the backend configuration.

Backend configuration contains fixed information about the backend, such as its name, number of qubits, basis gates, coupling map, quantum volume, etc.

The schema for backend configuration can be found in Qiskit/ibm-quantum-schemas/backend_configuration.

More details about backend configuration properties can be found here QasmBackendConfiguration.

IBM backends may also include the following properties:
  • supported_features: a list of strings of supported features like “qasm3” for dynamic

    circuits support.

  • parallel_compilation: a boolean of whether or not the backend can process multiple

    jobs at once. Parts of the classical computation will be parallelized.

Returns:

The configuration for the backend.

Return type:

QasmBackendConfiguration

get_translation_stage_plugin()[source]

Return the default translation stage plugin name for IBM backends.

Return type:

str

properties(refresh=False, datetime=None)[source]

Return the backend properties, subject to optional filtering.

This data describes qubits properties (such as T1 and T2), gates properties (such as gate length and error), and other general properties of the backend.

The schema for backend properties can be found in Qiskit/ibm-quantum-schemas/backend_properties.

Parameters:

  • refresh (bool) – If True, re-query the server for the backend properties. Otherwise, return a cached version.

  • datetime (datetime | None) – By specifying datetime, this function returns an instance of the BackendProperties whose timestamp is closest to, but older than, the specified datetime.

Returns:

The backend properties or None if the backend properties are not currently available.

Raises:

  • TypeError – If an input argument is not of the correct type.

  • NotImplementedError – If datetime is specified when cloud runtime is used.

Return type:

BackendProperties | None

qubit_properties(qubit)

Return QubitProperties for a given qubit.

If there are no defined or the backend doesn’t support querying these details this method does not need to be implemented.

Parameters:

qubit (int | List[int]) – The qubit to get the QubitProperties object for. This can be a single integer for 1 qubit or a list of qubits and a list of QubitProperties objects will be returned in the same order

Returns:

The QubitProperties object for the specified qubit. If a list of qubits is provided a list will be returned. If properties are missing for a qubit this can be None.

Raises:

NotImplementedError – if the backend doesn’t support querying the qubit properties

Return type:

QubitProperties | List[QubitProperties]

refresh()[source]

Retrieve the newest backend configuration and refresh the current backend target.

Return type:

None

run(*args, **kwargs)[source]
Raises:

IBMBackendError – The run() method is no longer supported.

Return type:

None

set_options(**fields)

Set the options fields for the backend

This method is used to update the options of a backend. If you need to change any of the options prior to running just pass in the kwarg with the new value for the options.

Parameters:

fields – The fields to update the options

Raises:

AttributeError – If the field passed in is not part of the options

status()[source]

Return the backend status.

Note

If the returned BackendStatus instance has operational=True but status_msg="internal", then the backend is accepting jobs but not processing them.

Returns:

The status of the backend.

Raises:

IBMBackendApiProtocolError – If the status for the backend cannot be formatted properly.

Return type:

BackendStatus

submit(program, options=None)[source]

Submit a quantum program for execution.

Parameters:
Returns:

A job.

Return type:

RuntimeJobV2

target_history(datetime=None)[source]

A qiskit.transpiler.Target object for the backend.

Returns:

Target with properties found on datetime

Parameters:

datetime (datetime | None)

Return type:

Target