Source code for qiskit_experiments.library.calibration.frequency_cal

# 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,
)




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)



    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,
        )