Flux-Drive timing

doc/source/protocols/index.rst

@@ -33,5 +33,7 @@ In this section we introduce the basics of all protocols supported by ``qibocal`
     standard_rb
     chevron
     virtual_z
+    xyz_timing
     state_tomographies
+
     references

doc/source/protocols/xyz_timing.rst

@@ -0,0 +1,35 @@
+XYZ-TIMING
+==========
+
+This routine is evaluating the different time of arrival of the flux and drive
+pulse to the qubit. These delays are usually originated by the differences in
+cable length or by the electronics.
+
+In this procedure, we vary the relative start times of the flux and drive pulses,
+keeping their durations identical.
+By measuring the probability of the qubit being in the excited state,
+we identify the point where the two pulses arrive simultaneously.
+At this point, the probability drops to zero because the qubit is off-resonance,
+allowing us to determine the delay.
+
+Parameters
+^^^^^^^^^^
+
+.. autoclass::
+	qibocal.protocols.xyz_timing.XYZTimingParameters
+	:noindex:
+
+Example
+^^^^^^^
+It follows a runcard example of this experiment and the report.
+
+.. code-block:: yaml
+
+    - id: xyz_timing
+      operation: xyz_timing
+      parameters:
+        delay_step: 1
+        delay_stop: 100
+        flux_amplitude: 0.3
+
+.. image:: xyz_timing.png

src/qibocal/protocols/__init__.py

@@ -52,6 +52,7 @@
     optimize_two_qubit_gate,
 )
 from .two_qubit_state_tomography import two_qubit_state_tomography
+from .xyz_timing import xyz_timing
 
 __all__ = [
     "allxy",
@@ -104,4 +105,5 @@
     "standard_rb_2q_inter",
     "optimize_two_qubit_gate",
     "ramsey_zz",
+    "xyz_timing",
 ]

src/qibocal/protocols/xyz_timing.py

@@ -0,0 +1,255 @@
+from dataclasses import dataclass, field
+
+import numpy as np
+import numpy.typing as npt
+import plotly.graph_objects as go
+from qibo.models.error_mitigation import curve_fit
+from qibolab import AcquisitionType, AveragingMode, Custom, Delay, Pulse, PulseSequence
+from scipy import special
+
+from qibocal.auto.operation import Data, Parameters, Results, Routine
+from qibocal.calibration.calibration import QubitId
+from qibocal.calibration.platform import CalibrationPlatform
+from qibocal.result import probability
+
+from .utils import table_dict, table_html
+
+COLORBAND = "rgba(0,100,80,0.2)"
+COLORBAND_LINE = "rgba(255,255,255,0)"
+PADDING_FLUX = 10
+
+
+@dataclass
+class XYZTimingResults(Results):
+    """Outputs of the xyz-timing protocol."""
+
+    fitted_parameters: dict[QubitId, list[float]]
+    """Output parameters of the fitted function."""
+    fitted_errors: dict[QubitId, list[float]]
+    """Errors of the fit parameters."""
+    delays: dict[QubitId, float]
+    """Flux-drive delays."""
+
+
+@dataclass
+class XYZTimingParameters(Parameters):
+    """XYZ-timing runcard inputs."""
+
+    flux_amplitude: float
+    """Amplitude of the flux pulse."""
+    delay_step: int
+    """Sweeper step value of the relative starts."""
+    delay_stop: int
+    """Sweeper stop value of the relative starts."""
+
+
+XYZTimingType = np.dtype(
+    [("delay", np.float64), ("prob", np.float64), ("errors", np.float64)]
+)
+
+
+@dataclass
+class XYZTimingData(Data):
+
+    pulse_duration: dict[QubitId, int]
+    """Duration of the drive and flux pulse"""
+    data: dict[QubitId, npt.NDArray] = field(default_factory=dict)
+    """Raw data acquired."""
+
+
+def _acquisition(
+    params: XYZTimingParameters,
+    platform: CalibrationPlatform,
+    targets: list[QubitId],
+) -> XYZTimingData:
+    """Data acquisition for drive-flux channels timing"""
+    natives = platform.natives.single_qubit
+    durations = np.arange(
+        1,
+        params.delay_stop,
+        params.delay_step,
+    )
+    sequences = []
+    ro_pulses = []
+    drive_durations = {}
+    for qubit in targets:
+        drive_pulse = natives[qubit].RX()[0]
+        drive_durations[qubit] = int(drive_pulse[1].duration)
+
+    data = XYZTimingData(pulse_duration=drive_durations)
+    for duration in durations:
+        ro_pulses.append([])
+        for qubit in targets:
+            sequence = PulseSequence()
+            drive_channel = platform.qubits[qubit].drive
+            flux_channel = platform.qubits[qubit].flux
+            ro_channel = platform.qubits[qubit].acquisition
+            drive_pulse = natives[qubit].RX()[0]
+            readout_pulse = natives[qubit].MZ()[0]
+            drive_duration = int(drive_pulse[1].duration)
+            total_flux_duration = duration + drive_duration + PADDING_FLUX
+            flux_pulse = Pulse(
+                duration=total_flux_duration,
+                amplitude=params.flux_amplitude,
+                relative_phase=0,
+                envelope=Custom(
+                    i_=np.concatenate(
+                        [
+                            np.zeros(duration),
+                            np.ones(drive_duration),
+                            np.zeros(PADDING_FLUX),
+                        ]
+                    ),
+                    q_=np.zeros(total_flux_duration),
+                ),
+            )
+            qd_delay = Delay(duration=drive_duration)
+
+            sequence.extend(
+                [
+                    (drive_channel, qd_delay),
+                    drive_pulse,
+                    (flux_channel, flux_pulse),
+                ]
+            )
+            sequence.align([drive_channel, flux_channel, ro_channel])
+            sequence.append(readout_pulse)
+            sequences.append(sequence)
+            ro_pulses[-1].append(readout_pulse)
+
+    results = platform.execute(
+        sequences,
+        nshots=params.nshots,
+        relaxation_time=params.relaxation_time,
+        acquisition_type=AcquisitionType.DISCRIMINATION,
+        averaging_mode=AveragingMode.SINGLESHOT,
+    )
+    for i, duration in enumerate(durations):
+        for j, qubit in enumerate(targets):
+            ro_pulse = ro_pulses[i][j][1]
+            prob = probability(results[ro_pulse.id], state=1)
+            error = np.sqrt(prob * (1 - prob) / params.nshots)
+            data.register_qubit(
+                XYZTimingType,
+                (qubit),
+                dict(
+                    delay=np.array([duration]),
+                    prob=np.array([prob]),
+                    errors=np.array([error]),
+                ),
+            )
+    return data
+
+
+def fit_function(x, a, b, c, d, e):
+    return a + b * (special.erf(e * x - c) - special.erf(e * x + d))
+
+
+def _fit(data: XYZTimingData) -> XYZTimingResults:
+    """Post-processing for drive-flux channels timing"""
+    qubits = data.qubits
+    params = {}
+    errors = {}
+    delays = {}
+    for qubit in qubits:
+        data_qubit = data.data[qubit]
+        delay = data_qubit.delay
+        prob = data_qubit.prob
+        err = data_qubit.errors
+        initial_pars = [
+            1,
+            0.5,
+            data.pulse_duration[qubit] / 2,
+            data.pulse_duration[qubit] / 2,
+            1,
+        ]
+        fit_parameters, perr = curve_fit(
+            fit_function,
+            delay - data.pulse_duration[qubit],
+            prob,
+            p0=initial_pars,
+            sigma=err,
+        )
+
+        err = np.sqrt(np.diag(perr)).tolist()
+        params[qubit] = fit_parameters.tolist()
+        errors[qubit] = err
+        delays[qubit] = [
+            (fit_parameters[2] - fit_parameters[3]) / (2 * fit_parameters[4]),
+            float(np.linalg.norm([err[2], err[3]]) / 2) / fit_parameters[4] ** 2,
+        ]
+    return XYZTimingResults(
+        fitted_parameters=params,
+        fitted_errors=errors,
+        delays=delays,
+    )
+
+
+def _plot(data: XYZTimingData, target: QubitId, fit: XYZTimingResults = None):
+    """Plotting function for drive-flux channels timing"""
+    figures = []
+    qubit_data = data.data[target]
+    delays = qubit_data.delay
+    probs = qubit_data.prob
+    error_bars = qubit_data.errors
+    x = delays - data.pulse_duration[target]
+    fitting_report = ""
+    fig = go.Figure(
+        [
+            go.Scatter(
+                x=x,
+                y=probs,
+                opacity=1,
+                name="Probability of State 1",
+                showlegend=True,
+                legendgroup="Probability of State 1",
+                mode="lines",
+            ),
+            go.Scatter(
+                x=np.concatenate((x, x[::-1])),
+                y=np.concatenate((probs + error_bars, (probs - error_bars)[::-1])),
+                fill="toself",
+                fillcolor=COLORBAND,
+                line=dict(color=COLORBAND_LINE),
+                showlegend=True,
+                name="Errors",
+            ),
+        ]
+    )
+    if fit is not None:
+        fig.add_trace(
+            go.Scatter(
+                x=x,
+                y=fit_function(x, *fit.fitted_parameters[target]),
+                opacity=1,
+                name="Fit",
+                showlegend=True,
+                legendgroup="Probability of State 0",
+                mode="lines",
+            ),
+        )
+        fig.add_vline(
+            x=fit.delays[target][0],
+            line=dict(color="grey", width=3, dash="dash"),
+        )
+        fitting_report = table_html(
+            table_dict(
+                target,
+                ["Flux pulse delay [ns]"],
+                [fit.delays[target]],
+                display_error=True,
+            )
+        )
+
+    fig.update_layout(
+        showlegend=True,
+        xaxis_title="Time [ns]",
+        yaxis_title="Excited state probability",
+    )
+
+    figures.append(fig)
+
+    return figures, fitting_report
+
+
+xyz_timing = Routine(_acquisition, _fit, _plot)

tests/runcards/protocols.yml

@@ -850,3 +850,10 @@ actions:
     parameters:
       nshots: 1024
       circuit: tests/circuit2q.json
+
+  - id: xyz_timing
+    operation: xyz_timing
+    parameters:
+      delay_step: 1
+      delay_stop: 10
+      flux_amplitude: 0.3