def test_noise_from_measurement():
# Verify that a moment with only measurement gates has no noise if
# skip_measurements is True.
q0, q1 = cirq.LineQubit.range(2)
gate_durations = {
cirq.ZPowGate: 25.0,
cirq.MeasurementGate: 4000.0,
}
heat_rate_GHz = {q1: 1e-5}
cool_rate_GHz = {q0: 1e-4}
model = ThermalNoiseModel(
qubits={q0, q1},
gate_durations_ns=gate_durations,
heat_rate_GHz=heat_rate_GHz,
cool_rate_GHz=cool_rate_GHz,
dephase_rate_GHz=None,
require_physical_tag=False,
skip_measurements=True,
)
moment = cirq.Moment(cirq.measure(q0, q1, key='m'))
assert model.noisy_moment(moment, system_qubits=[q0, q1]) == [moment]
part_measure_moment = cirq.Moment(cirq.measure(q0, key='m'), cirq.Z(q1))
assert len(model.noisy_moment(part_measure_moment,
system_qubits=[q0, q1])) == 2
model.skip_measurements = False
assert len(model.noisy_moment(moment, system_qubits=[q0, q1])) == 2
def test_noise_from_virtual_gates():
# Verify that a moment with only virtual gates has no noise if
# require_physical_tag is True.
q0, q1 = cirq.LineQubit.range(2)
gate_durations = {cirq.ZPowGate: 25.0}
heat_rate_GHz = {q1: 1e-5}
cool_rate_GHz = {q0: 1e-4}
model = ThermalNoiseModel(
qubits={q0, q1},
gate_durations_ns=gate_durations,
heat_rate_GHz=heat_rate_GHz,
cool_rate_GHz=cool_rate_GHz,
dephase_rate_GHz=None,
require_physical_tag=True,
skip_measurements=False,
)
moment = cirq.Moment(cirq.Z(q0), cirq.Z(q1))
assert model.noisy_moment(moment, system_qubits=[q0, q1]) == [moment]
part_virtual_moment = cirq.Moment(cirq.Z(q0),
cirq.Z(q1).with_tags(PHYSICAL_GATE_TAG))
with pytest.raises(ValueError, match="all physical or all virtual"):
_ = model.noisy_moment(part_virtual_moment, system_qubits=[q0, q1])
model.require_physical_tag = False
assert len(model.noisy_moment(moment, system_qubits=[q0, q1])) == 2
def test_noise_from_wait():
# Verify that wait-gate noise is duration-dependent.
q0 = cirq.LineQubit(0)
gate_durations = {cirq.ZPowGate: 25.0}
heat_rate_GHz = {q0: 1e-5}
cool_rate_GHz = {q0: 1e-4}
model = ThermalNoiseModel(
qubits={q0},
gate_durations_ns=gate_durations,
heat_rate_GHz=heat_rate_GHz,
cool_rate_GHz=cool_rate_GHz,
dephase_rate_GHz=None,
require_physical_tag=False,
skip_measurements=True,
)
moment = cirq.Moment(cirq.wait(q0, nanos=100))
noisy_moment = model.noisy_moment(moment, system_qubits=[q0])
assert noisy_moment[0] == moment
assert len(noisy_moment[1]) == 1
noisy_choi = cirq.kraus_to_choi(cirq.kraus(noisy_moment[1].operations[0]))
print(noisy_choi)
assert np.allclose(
noisy_choi,
[
[9.99005480e-01, 0, 0, 9.94515097e-01],
[0, 9.94520111e-03, 0, 0],
[0, 0, 9.94520111e-04, 0],
[9.94515097e-01, 0, 0, 9.90054799e-01],
],
)
def test_noisy_moment_two_qubit():
q0, q1 = cirq.LineQubit.range(2)
model = ThermalNoiseModel(
qubits={q0, q1},
gate_durations_ns={cirq.PhasedXZGate: 25.0, cirq.CZPowGate: 25.0},
heat_rate_GHz={q0: 1e-5, q1: 2e-5},
cool_rate_GHz={q0: 1e-4, q1: 2e-4},
dephase_rate_GHz={q0: 3e-4, q1: 4e-4},
require_physical_tag=False,
)
gate = cirq.CZ**0.5
moment = cirq.Moment(gate.on(q0, q1))
noisy_moment = model.noisy_moment(moment, system_qubits=[q0, q1])
assert noisy_moment[0] == moment
assert len(noisy_moment[1]) == 2
noisy_choi_0 = cirq.kraus_to_choi(cirq.kraus(noisy_moment[1].operations[0]))
assert np.allclose(
noisy_choi_0,
[
[9.99750343e-01, 0, 0, 9.91164267e-01],
[0, 2.49656565e-03, 0, 0],
[0, 0, 2.49656565e-04, 0],
[9.91164267e-01, 0, 0, 9.97503434e-01],
],
)
noisy_choi_1 = cirq.kraus_to_choi(cirq.kraus(noisy_moment[1].operations[1]))
assert np.allclose(
noisy_choi_1,
[
[9.99501372e-01, 0, 0, 9.87330937e-01],
[0, 4.98627517e-03, 0, 0],
[0, 0, 4.98627517e-04, 0],
[9.87330937e-01, 0, 0, 9.95013725e-01],
],
)
def test_noisy_moment_one_qubit():
q0, q1 = cirq.LineQubit.range(2)
model = ThermalNoiseModel(
qubits={q0, q1},
gate_durations_ns={cirq.PhasedXZGate: 25.0, cirq.CZPowGate: 25.0},
heat_rate_GHz={q0: 1e-5, q1: 2e-5},
cool_rate_GHz={q0: 1e-4, q1: 2e-4},
dephase_rate_GHz={q0: 3e-4, q1: 4e-4},
require_physical_tag=False,
)
gate = cirq.PhasedXZGate(x_exponent=1, z_exponent=0.5, axis_phase_exponent=0.25)
moment = cirq.Moment(gate.on(q0))
noisy_moment = model.noisy_moment(moment, system_qubits=[q0, q1])
assert noisy_moment[0] == moment
# Noise applies to both qubits, even if only one is acted upon.
assert len(noisy_moment[1]) == 2
noisy_choi = cirq.kraus_to_choi(cirq.kraus(noisy_moment[1].operations[0]))
assert np.allclose(
noisy_choi,
[
[9.99750343e-01, 0, 0, 9.91164267e-01],
[0, 2.49656565e-03, 0, 0],
[0, 0, 2.49656565e-04, 0],
[9.91164267e-01, 0, 0, 9.97503434e-01],
],
)
def test_noise_from_zero_duration():
# Verify that a moment with no duration has no noise.
q0, q1 = cirq.LineQubit.range(2)
gate_durations = {}
heat_rate_GHz = {q1: 1e-5}
cool_rate_GHz = {q0: 1e-4}
model = ThermalNoiseModel(
qubits={q0, q1},
gate_durations_ns=gate_durations,
heat_rate_GHz=heat_rate_GHz,
cool_rate_GHz=cool_rate_GHz,
dephase_rate_GHz=None,
require_physical_tag=False,
skip_measurements=False,
)
moment = cirq.Moment(cirq.Z(q0), cirq.Z(q1))
assert model.noisy_moment(moment, system_qubits=[q0, q1]) == [moment]
def test_symbolic_times_for_wait_gate():
q0 = cirq.LineQubit(0)
gate_durations = {cirq.ZPowGate: 25.0}
heat_rate_GHz = {q0: 1e-5}
cool_rate_GHz = {q0: 1e-4}
model = ThermalNoiseModel(
qubits={q0},
gate_durations_ns=gate_durations,
heat_rate_GHz=heat_rate_GHz,
cool_rate_GHz=cool_rate_GHz,
dephase_rate_GHz=None,
require_physical_tag=False,
skip_measurements=True,
)
moment = cirq.Moment(cirq.wait(q0, nanos=sympy.Symbol('t')))
with pytest.raises(ValueError, match='Symbolic'):
_ = model.noisy_moment(moment, system_qubits=[q0])