Flux Scope¶

Experiment to characterize the distortions of flux pulses due to the imperfect signal lines, following chapter 4.4.3 in https://www.research-collection.ethz.ch/handle/20.500.11850/153681

0. General Imports and Definitions¶

0.1 Python Imports¶

In [ ]:

# Helpers:
from laboneq.contrib.example_helpers.generate_device_setup import (
    generate_device_setup_qubits,
)
from laboneq.contrib.example_helpers.plotting.plot_helpers import *

# LabOne Q:
from laboneq.simple import *

# Helpers: from laboneq.contrib.example_helpers.generate_device_setup import ( generate_device_setup_qubits, ) from laboneq.contrib.example_helpers.plotting.plot_helpers import * # LabOne Q: from laboneq.simple import *

1. Device Setup¶

Below, you'll create a device setup and choose to run this notebook in emulated mode or directly on the control hardware, by specifying use_emulation = True/False respectively.

If you run on your hardware, you need to generate a device setup first, please have a look at our device setup tutorial for how to do this in general. Here, we use a helper functions to generate the device setup and a set up qubit objects with pre-defined parameters.

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# 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,
    pqsc=[{"serial": "DEV10001"}],
    hdawg=[
        {
            "serial": "DEV8001",
            "number_of_channels": 8,
            "options": None,
        }
    ],
    shfqc=[
        {
            "serial": "DEV12001",
            "number_of_channels": 6,
            "readout_multiplex": 6,
            "options": None,
        }
    ],
    multiplex_drive_lines=True,
    include_flux_lines=True,
    server_host="localhost",
    setup_name=f"my_{number_of_qubits}_tunable_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, pqsc=[{"serial": "DEV10001"}], hdawg=[ { "serial": "DEV8001", "number_of_channels": 8, "options": None, } ], shfqc=[ { "serial": "DEV12001", "number_of_channels": 6, "readout_multiplex": 6, "options": None, } ], multiplex_drive_lines=True, include_flux_lines=True, server_host="localhost", setup_name=f"my_{number_of_qubits}_tunable_qubit_setup", ) q0, q1 = qubits[:2]

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# use emulation mode - no connection to instruments
use_emulation = True

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

# use emulation mode - no connection to instruments use_emulation = True # create and connect to a session session = Session(device_setup=device_setup) session.connect(do_emulation=use_emulation)

2. Experiment Definition¶

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#  signal map for qubit
def map_qubit(qubit):
    return {
        "drive": qubit.signals["drive"],
        "flux": qubit.signals["flux"],
        "measure": qubit.signals["measure"],
        "acquire": qubit.signals["acquire"],
    }

# signal map for qubit def map_qubit(qubit): return { "drive": qubit.signals["drive"], "flux": qubit.signals["flux"], "measure": qubit.signals["measure"], "acquire": qubit.signals["acquire"], }

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# Pulse definitions
# qubit excitation pulse - amplitude such that if pulse is resonant, results in pi rotation
x180 = pulse_library.gaussian(uid="x180", length=20e-9, amplitude=0.66)

# flux pulse - constant length and amplitude
flux_pulse = pulse_library.const(uid="flux_pulse", length=400e-9, amplitude=0.5)

# readout drive pulse
readout_pulse = pulse_library.const(uid="readout_pulse", length=250e-9, amplitude=1.0)
# readout weights for integration
readout_weighting_function = pulse_library.const(
    uid="readout_weighting_function", length=200e-9, amplitude=1.0
)

# assuming all calibration settings are already correct

# Pulse definitions # qubit excitation pulse - amplitude such that if pulse is resonant, results in pi rotation x180 = pulse_library.gaussian(uid="x180", length=20e-9, amplitude=0.66) # flux pulse - constant length and amplitude flux_pulse = pulse_library.const(uid="flux_pulse", length=400e-9, amplitude=0.5) # readout drive pulse readout_pulse = pulse_library.const(uid="readout_pulse", length=250e-9, amplitude=1.0) # readout weights for integration readout_weighting_function = pulse_library.const( uid="readout_weighting_function", length=200e-9, amplitude=1.0 ) # assuming all calibration settings are already correct

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# define sweep parameters

# qubit excitation pulse frequency sweep
start_freq = 40e6
stop_freq = 200e6
count_freq = 11

sweep_frequency = LinearSweepParameter(
    uid="qubit_frequency", start=start_freq, stop=stop_freq, count=count_freq
)

# sweep delay between start of flux pulse and start of qubit excitation pulse
start_delay = 0
stop_delay = flux_pulse.length - x180.length
count_delay = 11

sweep_delay = LinearSweepParameter(
    uid="delay", start=start_delay, stop=stop_delay, count=count_delay
)

# define number of averages
average_exponent = 10  # used for 2^n averages, n=average_exponent, maximum: n = 19

# define sweep parameters # qubit excitation pulse frequency sweep start_freq = 40e6 stop_freq = 200e6 count_freq = 11 sweep_frequency = LinearSweepParameter( uid="qubit_frequency", start=start_freq, stop=stop_freq, count=count_freq ) # sweep delay between start of flux pulse and start of qubit excitation pulse start_delay = 0 stop_delay = flux_pulse.length - x180.length count_delay = 11 sweep_delay = LinearSweepParameter( uid="delay", start=start_delay, stop=stop_delay, count=count_delay ) # define number of averages average_exponent = 10 # used for 2^n averages, n=average_exponent, maximum: n = 19

2.1 Pulse Sequence¶

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# Create Experiment
exp = Experiment(
    "Flux Scope",
    signals=[
        ExperimentSignal("drive"),
        ExperimentSignal("flux"),
        ExperimentSignal("measure"),
        ExperimentSignal("acquire"),
    ],
)

## experimental pulse sequence
# outer sweep - qubit excitation frequency

# real-time acquisition loop in integration mode
with exp.acquire_loop_rt(
    uid="shots",
    count=pow(2, average_exponent),
    averaging_mode=AveragingMode.CYCLIC,
    acquisition_type=AcquisitionType.INTEGRATION,
):
    with exp.sweep(uid="frequency_sweep", parameter=sweep_frequency):
        # inner sweep - delay between start of qubit excitation pulse and start of flux pulse
        with exp.sweep(uid="sweep", parameter=sweep_delay):
            # flux pulse
            with exp.section(uid="qubit_excitation"):
                exp.play(signal="flux", pulse=flux_pulse)  # qubit detuning
                exp.delay(signal="drive", time=sweep_delay)  # delay is swept
                exp.play(signal="drive", pulse=x180)  # qubit excitation
            # readout and data acquisition
            with exp.section(uid="qubit_readout", play_after="qubit_excitation"):
                exp.play(signal="measure", pulse=readout_pulse)
                exp.acquire(
                    signal="acquire",
                    handle="ac_0",
                    kernel=readout_weighting_function,
                )
            # relax time after readout - for signal processing and qubit relaxation to ground state
            with exp.section(uid="relax", play_after="qubit_readout"):
                exp.delay(signal="measure", time=1e-6)

# Create Experiment exp = Experiment( "Flux Scope", signals=[ ExperimentSignal("drive"), ExperimentSignal("flux"), ExperimentSignal("measure"), ExperimentSignal("acquire"), ], ) ## experimental pulse sequence # outer sweep - qubit excitation frequency # real-time acquisition loop in integration mode with exp.acquire_loop_rt( uid="shots", count=pow(2, average_exponent), averaging_mode=AveragingMode.CYCLIC, acquisition_type=AcquisitionType.INTEGRATION, ): with exp.sweep(uid="frequency_sweep", parameter=sweep_frequency): # inner sweep - delay between start of qubit excitation pulse and start of flux pulse with exp.sweep(uid="sweep", parameter=sweep_delay): # flux pulse with exp.section(uid="qubit_excitation"): exp.play(signal="flux", pulse=flux_pulse) # qubit detuning exp.delay(signal="drive", time=sweep_delay) # delay is swept exp.play(signal="drive", pulse=x180) # qubit excitation # readout and data acquisition with exp.section(uid="qubit_readout", play_after="qubit_excitation"): exp.play(signal="measure", pulse=readout_pulse) exp.acquire( signal="acquire", handle="ac_0", kernel=readout_weighting_function, ) # relax time after readout - for signal processing and qubit relaxation to ground state with exp.section(uid="relax", play_after="qubit_readout"): exp.delay(signal="measure", time=1e-6)

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# define experiment calibration - sweep over qubit drive frequency
exp_calib = Calibration()
exp_calib["drive"] = SignalCalibration(
    oscillator=Oscillator(
        frequency=sweep_frequency,
        modulation_type=ModulationType.HARDWARE,
    )
)

# define experiment calibration - sweep over qubit drive frequency exp_calib = Calibration() exp_calib["drive"] = SignalCalibration( oscillator=Oscillator( frequency=sweep_frequency, modulation_type=ModulationType.HARDWARE, ) )

2.2 Run the Experiment and Plot the Measurement Results and Pulse Sequence¶

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# set calibration and signal map for qubit 0
exp.set_calibration(exp_calib)
exp.set_signal_map(map_qubit(q0))

# run experiment on qubit 0
my_results = session.run(exp)

# set calibration and signal map for qubit 0 exp.set_calibration(exp_calib) exp.set_signal_map(map_qubit(q0)) # run experiment on qubit 0 my_results = session.run(exp)

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# Plot simulated output signals
plot_simulation(session.compiled_experiment, start_time=0, length=10e-6)

# Plot simulated output signals plot_simulation(session.compiled_experiment, start_time=0, length=10e-6)

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# plot measurement results
plot_result_3d(my_results, "ac_0")

# plot measurement results plot_result_3d(my_results, "ac_0")

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# use pulse sheet viewer to display the pulse sequence - only recommended for small number of averages and sweep steps to avoid performance issues
show_pulse_sheet("Flux Scope Experiment", session.compiled_experiment)

# use pulse sheet viewer to display the pulse sequence - only recommended for small number of averages and sweep steps to avoid performance issues show_pulse_sheet("Flux Scope Experiment", session.compiled_experiment)

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# set calibration and signal map for qubit 1
exp.set_calibration(exp_calib)
exp.set_signal_map(map_qubit(q1))

# run experiment on qubit 1
my_results = session.run(exp)

# set calibration and signal map for qubit 1 exp.set_calibration(exp_calib) exp.set_signal_map(map_qubit(q1)) # run experiment on qubit 1 my_results = session.run(exp)

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