# This code is part of Qiskit.
#
# (C) Copyright IBM 2021.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.
"""Ramsey XY frequency calibration experiment."""
from typing import Dict, List, Optional, Sequence
from qiskit.circuit import QuantumCircuit
from qiskit.providers.backend import Backend
from qiskit_experiments.framework import ExperimentData
from qiskit_experiments.library.characterization.ramsey_xy import RamseyXY
from qiskit_experiments.calibration_management.calibrations import Calibrations
from qiskit_experiments.calibration_management.update_library import BaseUpdater
from qiskit_experiments.calibration_management.base_calibration_experiment import (
BaseCalibrationExperiment,
)
[docs]
class FrequencyCal(BaseCalibrationExperiment, RamseyXY):
"""A qubit frequency calibration experiment based on the Ramsey XY experiment."""
def __init__(
self,
physical_qubits: Sequence[int],
calibrations: Calibrations,
backend: Optional[Backend] = None,
cal_parameter_name: Optional[str] = "drive_freq",
delays: Optional[List] = None,
osc_freq: float = 2e6,
auto_update: bool = True,
):
"""
Args:
physical_qubits: Sequence containing the qubit on which to run the
frequency calibration.
calibrations: The calibrations instance with the schedules.
backend: Optional, the backend to run the experiment on.
cal_parameter_name: The name of the parameter to update in the calibrations.
This defaults to `drive_freq`.
delays: The list of delays that will be scanned in the experiment, in seconds.
osc_freq: A frequency shift in Hz that will be applied by means of
a virtual Z rotation to increase the frequency of the measured oscillation.
auto_update: If set to True, which is the default, then the experiment will
automatically update the frequency in the calibrations.
"""
super().__init__(
calibrations,
physical_qubits,
backend=backend,
delays=delays,
osc_freq=osc_freq,
cal_parameter_name=cal_parameter_name,
auto_update=auto_update,
)
def _metadata(self) -> Dict[str, any]:
"""Add the oscillation frequency of the experiment to the metadata."""
metadata = super()._metadata()
metadata["osc_freq"] = self.experiment_options.osc_freq
metadata["cal_param_value"] = self._cals.get_parameter_value(
self._param_name,
self.physical_qubits,
group=self.experiment_options.group,
)
return metadata
def _attach_calibrations(self, circuit: QuantumCircuit):
"""Adds the calibrations to the transpiled circuits."""
schedule = self._cals.get_schedule("sx", self.physical_qubits)
circuit.add_calibration("sx", self.physical_qubits, schedule)
[docs]
def update_calibrations(self, experiment_data: ExperimentData):
"""Update the frequency using the reported frequency less the imparted oscillation."""
result_index = self.experiment_options.result_index
osc_freq = experiment_data.metadata["osc_freq"]
group = experiment_data.metadata["cal_group"]
old_freq = experiment_data.metadata["cal_param_value"]
fit_freq = BaseUpdater.get_value(experiment_data, "freq", result_index)
new_freq = old_freq + fit_freq - osc_freq
BaseUpdater.add_parameter_value(
self._cals,
experiment_data,
new_freq,
self._param_name,
group=group,
)