Job fails when using PulseSimulator: Job Status: job incurred error

Question

I'm trying to simulate a basic circuit using the PulseSimulator in Qiskit. The following Qiskit Pulse code works when I run it on the real device, but not when using the PulseSimulator. The job monitor tells me Job Status: job incurred error and nothing else.

Trying to run any gates native to the device causes an issue. If I remove schedule += inst_sched_map.get('u2', [qubit], P0=0.0, P1=np.pi) then it runs fine, but I can't figure out what I'm doing wrong. I'd deeply appreciate any support. I'm using qiskit 0.23.2

#Essential Imports 
import numpy as np
# Qiskit Imports
from qiskit.providers.aer import PulseSimulator
from qiskit import IBMQ, assemble
from qiskit.tools.monitor import job_monitor
import qiskit.pulse as pulse

# Connect to an IBMQ Account and Backend
API_TOKEN = ''
IBMQ.save_account(API_TOKEN, overwrite=True)
IBMQ.load_account()
provider = IBMQ.get_provider()
backend = provider.get_backend("ibmq_armonk")
backend_pulse_simulator = PulseSimulator.from_backend(backend) #backend

# Get information about the backend
qubit = 0
backend_defaults = backend.defaults()
backend_properties = backend.properties()
qubit_frequency_updated = backend_properties.qubit_property(qubit, 'frequency')[0]
inst_sched_map = backend_defaults.instruction_schedule_map
measure_schedule = inst_sched_map.get('measure', qubits=[qubit])

# Assemble a job - circuit with a single qubit-> u2 gate -> measurement
num_shots_per_point = 1024
drive_chan = pulse.DriveChannel(qubit)
schedule = pulse.Schedule()
schedule += inst_sched_map.get('u2', [qubit], P0=0.0, P1=np.pi) # Removing this solves the issue - why?
schedule += measure_schedule << schedule.duration               
pulse_program = assemble(schedule, 
                        backend=backend_pulse_simulator, 
                        meas_level=2, meas_return="single",
                        shots=num_shots_per_point,
                        schedule_los=[{drive_chan: qubit_frequency_updated}])

# Run the job
job = backend_pulse_simulator.run(pulse_program)
job_monitor(job)

Answer 1

The Job Status: job incurred error with pulse can be the result of a timing problem in the execution of different pulses, but in your code the PulseSimulator() class must get backends provided by Terra such as FakeArmonk(), FakeParis()..etc. For example:

from qiskit.test.mock import FakeArmonk
backend=FakeArmonk()
backend_pulse_simulator = PulseSimulator.from_backend(backend) # using FakeArmonk() backend
print(type(backend_pulse_simulator))

The FakeBackends() have the properties of the IBM Quantum devices data and are stored in Qiskit Terra.

Another way is to specify a PulseSystemModel() from a real backend and pass the system model to the execution method. Below is an example with ibmq_armonk.

from qiskit.providers.aer.pulse import PulseSystemModel
from qiskit.providers.aer import PulseSimulator

armonk_backend= provider.get_backend("ibmq_armonk")
armonk_model = PulseSystemModel.from_backend(armonk_backend)
backend_pulse_simulator=PulseSimulator()
job = backend_pulse_simulator.run(pulse_program, armonk_model)

hope this helps

Patrick