Waveform Replacement¶

In this notebook, you'll learn how to use a callback function in a near-time sweep to perform a waveform replacement experiment. This kind of functionality can be adapted to your own experiment, e.g., VQE or optimal control.

General Imports and Definitions¶

In [ ]:

# LabOne Q:
# Other imports
from pathlib import Path

import numpy as np

# Helper files for fitting and plotting
from laboneq.contrib.example_helpers.generate_device_setup import (
    generate_device_setup_qubits,
)
from laboneq.contrib.example_helpers.plotting.plot_helpers import plot_simulation
from laboneq.simple import *

# LabOne Q: # Other imports from pathlib import Path import numpy as np # Helper files for fitting and plotting from laboneq.contrib.example_helpers.generate_device_setup import ( generate_device_setup_qubits, ) from laboneq.contrib.example_helpers.plotting.plot_helpers import plot_simulation from laboneq.simple import *

Create Device Setup¶

Generate the device setup and some qubit objects from pre-defined parameters in a helper file

In [ ]:

# specify the number of qubits you want to use
number_of_qubits = 2

# generate the device setup and the qubit objects using a helper function
device_setup, qubits = generate_device_setup_qubits(
    number_qubits=number_of_qubits,
    shfqc=[
        {
            "serial": "DEV12001",
            "zsync": 1,
            "number_of_channels": 6,
            "readout_multiplex": 6,
            "options": None,
        }
    ],
    include_flux_lines=False,
    server_host="localhost",
    setup_name=f"my_{number_of_qubits}_fixed_qubit_setup",
)

q0, q1 = qubits[:2]

# specify the number of qubits you want to use number_of_qubits = 2 # generate the device setup and the qubit objects using a helper function device_setup, qubits = generate_device_setup_qubits( number_qubits=number_of_qubits, shfqc=[ { "serial": "DEV12001", "zsync": 1, "number_of_channels": 6, "readout_multiplex": 6, "options": None, } ], include_flux_lines=False, server_host="localhost", setup_name=f"my_{number_of_qubits}_fixed_qubit_setup", ) q0, q1 = qubits[:2]

Create and Connect to a QCCS Session¶

In [ ]:

# perform experiments in emulation mode only? - if True, also generate dummy data for fitting
emulate = True

# create and connect to a session
session = Session(device_setup=device_setup)
session.connect(do_emulation=emulate)

# perform experiments in emulation mode only? - if True, also generate dummy data for fitting emulate = True # create and connect to a session session = Session(device_setup=device_setup) session.connect(do_emulation=emulate)

Pulse Exchange Experiment¶

Pulse Definitions¶

Below, we define the pulse definitions to be used in the experiment. The only restriction is that pulses must be of the same length of those that they are replacing.

In [ ]:

pulse_length = 256  # in samples
pulse_time = 256 / 2.0e9  # in seconds

# first pulse - constant, square pulse
p_const = pulse_library.const(uid="const", length=pulse_time, amplitude=1)

# second pulse - gaussian
p_gauss = pulse_library.gaussian(
    uid="gauss", length=pulse_time, amplitude=0.8, sigma=0.3
)

# third pulse - drag
p_drag = pulse_library.drag(
    uid="drag", length=pulse_time, amplitude=1, sigma=0.3, beta=0.1
)


# user defined pulse
@pulse_library.register_pulse_functional
def flattop_gaussian(x, relative_length_flat=0.6, **_):
    sigma = (1 - relative_length_flat) / 3
    res = np.ones(len(x))

    res[x <= -relative_length_flat] = np.exp(
        -((x[x <= -relative_length_flat] + relative_length_flat) ** 2) / (2 * sigma**2)
    )
    res[x >= relative_length_flat] = np.exp(
        -((x[x >= relative_length_flat] - relative_length_flat) ** 2) / (2 * sigma**2)
    )

    return res


p_flattop = flattop_gaussian(uid="flattop", length=pulse_time, amplitude=1)

pulse_length = 256 # in samples pulse_time = 256 / 2.0e9 # in seconds # first pulse - constant, square pulse p_const = pulse_library.const(uid="const", length=pulse_time, amplitude=1) # second pulse - gaussian p_gauss = pulse_library.gaussian( uid="gauss", length=pulse_time, amplitude=0.8, sigma=0.3 ) # third pulse - drag p_drag = pulse_library.drag( uid="drag", length=pulse_time, amplitude=1, sigma=0.3, beta=0.1 ) # user defined pulse @pulse_library.register_pulse_functional def flattop_gaussian(x, relative_length_flat=0.6, **_): sigma = (1 - relative_length_flat) / 3 res = np.ones(len(x)) res[x <= -relative_length_flat] = np.exp( -((x[x <= -relative_length_flat] + relative_length_flat) ** 2) / (2 * sigma**2) ) res[x >= relative_length_flat] = np.exp( -((x[x >= relative_length_flat] - relative_length_flat) ** 2) / (2 * sigma**2) ) return res p_flattop = flattop_gaussian(uid="flattop", length=pulse_time, amplitude=1)

Replace pulse function¶

Below, we define the function to replace our pulse with another.

In [ ]:

def neartime_callback_to_replace_pulse(session: Session, idx):
    # take pulse index and replace
    if idx > 0.5 and idx < 1.5:
        # replace library pulse with library pulse
        session.replace_pulse(p_flattop, p_gauss)
        print(f"{idx} First replacement: p_flattop replaced by p_gauss")
        return
    elif idx > 1.5 and idx < 2.5:
        # replace library pulse with library pulse
        session.replace_pulse(p_gauss, p_drag)
        print(f"{idx} Second replacement: p_gauss replaced by p_drag")
        return
    elif idx > 2.5:
        # replace library pulse with sampled pulse
        session.replace_pulse(p_drag, p_const)
        print(f"{idx} Third replacement: p_drag replaced by p_const")
        return
    print(idx)
    return

def neartime_callback_to_replace_pulse(session: Session, idx): # take pulse index and replace if idx > 0.5 and idx < 1.5: # replace library pulse with library pulse session.replace_pulse(p_flattop, p_gauss) print(f"{idx} First replacement: p_flattop replaced by p_gauss") return elif idx > 1.5 and idx < 2.5: # replace library pulse with library pulse session.replace_pulse(p_gauss, p_drag) print(f"{idx} Second replacement: p_gauss replaced by p_drag") return elif idx > 2.5: # replace library pulse with sampled pulse session.replace_pulse(p_drag, p_const) print(f"{idx} Third replacement: p_drag replaced by p_const") return print(idx) return

Experiment definition¶

In our experiment, we increase an index (instance_idx) where, once the index increases over the threshold set in the above near-time callback, once pulse is replaced with another.

In [ ]:

def exp_waveform_exchange(
    count,
    qubit=q0,
):
    exp = Experiment(
        signals=[ExperimentSignal("drive", map_to=qubit.signals["drive"])],
        uid="Exchange Experiment",
    )

    instance_idx = LinearSweepParameter(
        uid="x90_instance_idx", start=0, stop=3, count=count
    )

    # pulse index sweep in near time
    with exp.sweep(uid="x90_tune", parameter=instance_idx):
        # acquisition loop
        with exp.acquire_loop_rt(
            uid="shots", count=1, acquisition_type=AcquisitionType.INTEGRATION
        ):
            # play a sequence of pulses
            with exp.section(uid="play"):
                exp.play(signal="drive", pulse=p_flattop, phase=0)

                exp.delay(signal="drive", time=25e-9)

                exp.play(signal="drive", pulse=p_gauss)

                exp.delay(signal="drive", time=25e-9)

                exp.play(signal="drive", pulse=p_drag, phase=np.pi / 2.0, amplitude=0.3)

                exp.delay(signal="drive", time=25e-9)

                exp.play(signal="drive", pulse=p_gauss, length=50e-9)

                exp.delay(signal="drive", time=0.5)

        # replace pulses with a callback function
        exp.call(neartime_callback_to_replace_pulse, idx=instance_idx)

    calibration = Calibration({"drive": qubit.calibration()[f"{qubit.uid}/drive"]})
    exp.set_calibration(calibration)
    return exp

def exp_waveform_exchange( count, qubit=q0, ): exp = Experiment( signals=[ExperimentSignal("drive", map_to=qubit.signals["drive"])], uid="Exchange Experiment", ) instance_idx = LinearSweepParameter( uid="x90_instance_idx", start=0, stop=3, count=count ) # pulse index sweep in near time with exp.sweep(uid="x90_tune", parameter=instance_idx): # acquisition loop with exp.acquire_loop_rt( uid="shots", count=1, acquisition_type=AcquisitionType.INTEGRATION ): # play a sequence of pulses with exp.section(uid="play"): exp.play(signal="drive", pulse=p_flattop, phase=0) exp.delay(signal="drive", time=25e-9) exp.play(signal="drive", pulse=p_gauss) exp.delay(signal="drive", time=25e-9) exp.play(signal="drive", pulse=p_drag, phase=np.pi / 2.0, amplitude=0.3) exp.delay(signal="drive", time=25e-9) exp.play(signal="drive", pulse=p_gauss, length=50e-9) exp.delay(signal="drive", time=0.5) # replace pulses with a callback function exp.call(neartime_callback_to_replace_pulse, idx=instance_idx) calibration = Calibration({"drive": qubit.calibration()[f"{qubit.uid}/drive"]}) exp.set_calibration(calibration) return exp

Compilation¶

In [ ]:

# register near-time callback in session
session.register_neartime_callback(neartime_callback_to_replace_pulse)

# compile
comp_waveform_replacement = session.compile(exp_waveform_exchange(30))

# register near-time callback in session session.register_neartime_callback(neartime_callback_to_replace_pulse) # compile comp_waveform_replacement = session.compile(exp_waveform_exchange(30))

Simulation¶

Here, the simulation shows the first real-time pulse sequence, before the pulses are replaced using our near-time callback.

In [ ]:

plot_simulation(comp_waveform_replacement, start_time=0, length=1e-6)

plot_simulation(comp_waveform_replacement, start_time=0, length=1e-6)

Create pulse sheet¶

In [ ]:

Path("Pulse_sheets").mkdir(parents=True, exist_ok=True)
show_pulse_sheet("Pulse_sheets/waveform_replacement", comp_waveform_replacement)

Path("Pulse_sheets").mkdir(parents=True, exist_ok=True) show_pulse_sheet("Pulse_sheets/waveform_replacement", comp_waveform_replacement)

Run experiment¶

In [ ]:

# run the compiled experiemnt
waveform_replacement_results = session.run(comp_waveform_replacement)

# run the compiled experiemnt waveform_replacement_results = session.run(comp_waveform_replacement)