Ramsey with a sampled pulse¶

This notebook demonstrates the use of a sampled pulse in a Ramsey experiment. We sweep the delay between two slightly detuned pi/2 pulses to determine the qubit dephasing time as well as fine calibration its excited state frequency and use a user defined pulse, given as complex valued numpy array.

0. General Imports and Definitions¶

0.1 Python Imports¶

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import numpy as np

# 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 *

import numpy as np # 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",
            "zsync": 0,
            "number_of_channels": 8,
            "options": None,
        }
    ],
    shfqc=[
        {
            "serial": "DEV12001",
            "zsync": 1,
            "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", "zsync": 0, "number_of_channels": 8, "options": None, } ], shfqc=[ { "serial": "DEV12001", "zsync": 1, "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"],
        "measure": qubit.signals["measure"],
        "acquire": qubit.signals["acquire"],
    }

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

2.1 Pulse definition¶

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## define pulses
# A setup consisting of SHF instruments and HDAWGs has a sampling rate of 2 GSa/s
drive_sampling_rate = 2.0e9

# qubit drive pulse as sampled complex pulse
x90_length = 100e-9
num_samples = round(x90_length * drive_sampling_rate)
samples_complex = np.array(
    np.arange(num_samples) * (1 / num_samples)
    + 1j * np.arange(num_samples) * (1 / num_samples),
    dtype=np.complex128,
)

x90 = pulse_library.sampled_pulse(samples=samples_complex, uid="x90")
# readout drive pulse
readout_pulse = pulse_library.const(uid="readout_pulse", length=400e-9, amplitude=1.0)
# readout integration weights
readout_weighting_function = pulse_library.const(
    uid="readout_weighting_function", length=200e-9, amplitude=1.0
)

## define pulses # A setup consisting of SHF instruments and HDAWGs has a sampling rate of 2 GSa/s drive_sampling_rate = 2.0e9 # qubit drive pulse as sampled complex pulse x90_length = 100e-9 num_samples = round(x90_length * drive_sampling_rate) samples_complex = np.array( np.arange(num_samples) * (1 / num_samples) + 1j * np.arange(num_samples) * (1 / num_samples), dtype=np.complex128, ) x90 = pulse_library.sampled_pulse(samples=samples_complex, uid="x90") # readout drive pulse readout_pulse = pulse_library.const(uid="readout_pulse", length=400e-9, amplitude=1.0) # readout integration weights readout_weighting_function = pulse_library.const( uid="readout_weighting_function", length=200e-9, amplitude=1.0 )

2.2 Pulse Sequence¶

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# set up sweep parameter - delay between pi/2 pulses
start = 0.0
stop = 1000e-9
count = 11

delay_sweep = LinearSweepParameter(uid="delay", start=start, stop=stop, count=count)

# number of averages
average_exponent = 1  # used for 2^n averages, n=average_exponent, maximum: n = 17

# Create Experiment
exp = Experiment(
    uid="Ramsey",
    signals=[
        ExperimentSignal("drive"),
        ExperimentSignal("measure"),
        ExperimentSignal("acquire"),
    ],
)
## experimental sequence
# outer loop - real-time, cyclic averaging in standard integration mode
with exp.acquire_loop_rt(
    uid="shots",
    count=pow(2, average_exponent),
    averaging_mode=AveragingMode.CYCLIC,
    acquisition_type=AcquisitionType.INTEGRATION,
):
    # inner loop - sweep over delay between qubit drive pulses
    with exp.sweep(
        uid="sweep", parameter=delay_sweep, alignment=SectionAlignment.RIGHT
    ):
        # qubit excitation pulses - use right-aligned, constant length section to optimize pulse timings
        with exp.section(
            uid="qubit_excitation",
            length=stop + 2 * x90_length,
            alignment=SectionAlignment.RIGHT,
        ):
            exp.play(signal="drive", pulse=x90)
            exp.delay(signal="drive", time=delay_sweep)
            exp.play(signal="drive", pulse=x90)
        # qubit readout pulse and data acquisition
        with exp.section(uid="qubit_readout", play_after="qubit_excitation"):
            # play readout pulse
            exp.play(signal="measure", pulse=readout_pulse)
            # signal data acquisition
            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)

# set up sweep parameter - delay between pi/2 pulses start = 0.0 stop = 1000e-9 count = 11 delay_sweep = LinearSweepParameter(uid="delay", start=start, stop=stop, count=count) # number of averages average_exponent = 1 # used for 2^n averages, n=average_exponent, maximum: n = 17 # Create Experiment exp = Experiment( uid="Ramsey", signals=[ ExperimentSignal("drive"), ExperimentSignal("measure"), ExperimentSignal("acquire"), ], ) ## experimental sequence # outer loop - real-time, cyclic averaging in standard integration mode with exp.acquire_loop_rt( uid="shots", count=pow(2, average_exponent), averaging_mode=AveragingMode.CYCLIC, acquisition_type=AcquisitionType.INTEGRATION, ): # inner loop - sweep over delay between qubit drive pulses with exp.sweep( uid="sweep", parameter=delay_sweep, alignment=SectionAlignment.RIGHT ): # qubit excitation pulses - use right-aligned, constant length section to optimize pulse timings with exp.section( uid="qubit_excitation", length=stop + 2 * x90_length, alignment=SectionAlignment.RIGHT, ): exp.play(signal="drive", pulse=x90) exp.delay(signal="drive", time=delay_sweep) exp.play(signal="drive", pulse=x90) # qubit readout pulse and data acquisition with exp.section(uid="qubit_readout", play_after="qubit_excitation"): # play readout pulse exp.play(signal="measure", pulse=readout_pulse) # signal data acquisition 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)

2.3 Run the Experiment and Plot the Measurement Results and Pulse Sheet¶

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# map exp to qubit 0
exp.set_signal_map(map_qubit(q0))

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

# map exp to qubit 0 exp.set_signal_map(map_qubit(q0)) # run 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_2d(my_results, "ac_0")

# plot measurement results plot_result_2d(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("T1", 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("T1", session.compiled_experiment)

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# map exp to qubit 1
exp.set_signal_map(map_qubit(q1))

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

# map exp to qubit 1 exp.set_signal_map(map_qubit(q1)) # run on qubit 1 my_results = session.run(exp)

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