def test_two_qubit_gates(op):
q0, q1 = cirq.LineQubit.range(2)
props = TestNoiseProperties(
**default_props([q0, q1], [(q0, q1), (q1, q0)]))
model = NoiseModelFromNoiseProperties(props)
circuit = cirq.Circuit(op)
noisy_circuit = circuit.with_noise(model)
assert len(noisy_circuit.moments) == 3
assert len(noisy_circuit.moments[0].operations) == 1
assert noisy_circuit.moments[0].operations[0] == op.with_tags(
PHYSICAL_GATE_TAG)
# Depolarizing noise
assert len(noisy_circuit.moments[1].operations) == 1
depol_op = noisy_circuit.moments[1].operations[0]
assert isinstance(depol_op.gate, cirq.DepolarizingChannel)
assert np.isclose(depol_op.gate.p, 0.00952008)
# Thermal noise
assert len(noisy_circuit.moments[2].operations) == 2
thermal_op_0 = noisy_circuit.moments[2].operation_at(q0)
thermal_op_1 = noisy_circuit.moments[2].operation_at(q1)
assert isinstance(thermal_op_0.gate, cirq.KrausChannel)
assert isinstance(thermal_op_1.gate, cirq.KrausChannel)
thermal_choi_0 = cirq.kraus_to_choi(cirq.kraus(thermal_op_0))
thermal_choi_1 = cirq.kraus_to_choi(cirq.kraus(thermal_op_1))
expected_thermal_choi = np.array([
[1, 0, 0, 9.99680051e-01],
[0, 3.19948805e-04, 0, 0],
[0, 0, 0, 0],
[9.99680051e-01, 0, 0, 9.99680051e-01],
])
assert np.allclose(thermal_choi_0, expected_thermal_choi)
assert np.allclose(thermal_choi_1, expected_thermal_choi)
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_two_qubit_gates(op):
q0, q1 = cirq.LineQubit.range(2)
props = sample_noise_properties([q0, q1], [(q0, q1), (q1, q0)])
model = NoiseModelFromGoogleNoiseProperties(props)
circuit = cirq.Circuit(op)
noisy_circuit = circuit.with_noise(model)
assert len(noisy_circuit.moments) == 4
assert len(noisy_circuit.moments[0].operations) == 1
assert noisy_circuit.moments[0].operations[0] == op.with_tags(
PHYSICAL_GATE_TAG)
# Depolarizing noise
assert len(noisy_circuit.moments[1].operations) == 1
depol_op = noisy_circuit.moments[1].operations[0]
assert isinstance(depol_op.gate, cirq.DepolarizingChannel)
assert np.isclose(depol_op.gate.p, 0.00719705)
# FSim angle corrections
assert len(noisy_circuit.moments[2].operations) == 1
fsim_op = noisy_circuit.moments[2].operations[0]
assert isinstance(fsim_op.gate, cirq.PhasedFSimGate)
assert fsim_op == PhasedFSimGate(theta=0.01,
zeta=0.03,
chi=0.04,
gamma=0.05,
phi=0.02).on(q0, q1)
# Thermal noise
assert len(noisy_circuit.moments[3].operations) == 2
thermal_op_0 = noisy_circuit.moments[3].operation_at(q0)
thermal_op_1 = noisy_circuit.moments[3].operation_at(q1)
assert isinstance(thermal_op_0.gate, cirq.KrausChannel)
assert isinstance(thermal_op_1.gate, cirq.KrausChannel)
thermal_choi_0 = cirq.kraus_to_choi(cirq.kraus(thermal_op_0))
thermal_choi_1 = cirq.kraus_to_choi(cirq.kraus(thermal_op_1))
expected_thermal_choi = np.array([
[1, 0, 0, 9.99680051e-01],
[0, 3.19948805e-04, 0, 0],
[0, 0, 0, 0],
[9.99680051e-01, 0, 0, 9.99680051e-01],
])
assert np.allclose(thermal_choi_0, expected_thermal_choi)
assert np.allclose(thermal_choi_1, expected_thermal_choi)
# Pauli error for depol_op + fsim_op + thermal_op_(0|1) == total (0.01)
depol_pauli_err = 1 - cirq.qis.measures.entanglement_fidelity(depol_op)
fsim_pauli_err = 1 - cirq.qis.measures.entanglement_fidelity(fsim_op)
thermal0_pauli_err = 1 - cirq.qis.measures.entanglement_fidelity(
thermal_op_0)
thermal1_pauli_err = 1 - cirq.qis.measures.entanglement_fidelity(
thermal_op_1)
total_err = depol_pauli_err + thermal0_pauli_err + thermal1_pauli_err + fsim_pauli_err
assert np.isclose(total_err, TWO_QUBIT_ERROR)
def test_wait_gates():
q0 = cirq.LineQubit(0)
props = sample_noise_properties([q0], [])
model = NoiseModelFromGoogleNoiseProperties(props)
op = cirq.wait(q0, nanos=100)
circuit = cirq.Circuit(op)
noisy_circuit = circuit.with_noise(model)
assert len(noisy_circuit.moments) == 2
assert noisy_circuit.moments[0].operations[0] == op.with_tags(PHYSICAL_GATE_TAG)
# No depolarizing noise because WaitGate has none.
assert len(noisy_circuit.moments[1].operations) == 1
thermal_op = noisy_circuit.moments[1].operations[0]
assert isinstance(thermal_op.gate, cirq.KrausChannel)
thermal_choi = cirq.kraus_to_choi(cirq.kraus(thermal_op))
assert np.allclose(
thermal_choi,
[
[1, 0, 0, 9.990005e-01],
[0, 9.99500167e-04, 0, 0],
[0, 0, 0, 0],
[9.990005e-01, 0, 0, 9.990005e-01],
],
)
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_single_qubit_gates(op):
q0 = cirq.LineQubit(0)
props = TestNoiseProperties(**default_props([q0], []))
model = NoiseModelFromNoiseProperties(props)
circuit = cirq.Circuit(op)
noisy_circuit = circuit.with_noise(model)
assert len(noisy_circuit.moments) == 3
assert len(noisy_circuit.moments[0].operations) == 1
assert noisy_circuit.moments[0].operations[0] == op.with_tags(
PHYSICAL_GATE_TAG)
# Depolarizing noise
assert len(noisy_circuit.moments[1].operations) == 1
depol_op = noisy_circuit.moments[1].operations[0]
assert isinstance(depol_op.gate, cirq.DepolarizingChannel)
assert np.isclose(depol_op.gate.p, 0.00081252)
# Thermal noise
assert len(noisy_circuit.moments[2].operations) == 1
thermal_op = noisy_circuit.moments[2].operations[0]
assert isinstance(thermal_op.gate, cirq.KrausChannel)
thermal_choi = cirq.kraus_to_choi(cirq.kraus(thermal_op))
assert np.allclose(
thermal_choi,
[
[1, 0, 0, 9.99750031e-01],
[0, 2.49968753e-04, 0, 0],
[0, 0, 0, 0],
[9.99750031e-01, 0, 0, 9.99750031e-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_single_qubit_gates(op):
q0 = cirq.LineQubit(0)
props = sample_noise_properties([q0], [])
model = NoiseModelFromGoogleNoiseProperties(props)
circuit = cirq.Circuit(op)
noisy_circuit = circuit.with_noise(model)
assert len(noisy_circuit.moments) == 3
assert len(noisy_circuit.moments[0].operations) == 1
assert noisy_circuit.moments[0].operations[0] == op.with_tags(
PHYSICAL_GATE_TAG)
# Depolarizing noise
assert len(noisy_circuit.moments[1].operations) == 1
depol_op = noisy_circuit.moments[1].operations[0]
assert isinstance(depol_op.gate, cirq.DepolarizingChannel)
assert np.isclose(depol_op.gate.p, 0.00081252)
# Thermal noise
assert len(noisy_circuit.moments[2].operations) == 1
thermal_op = noisy_circuit.moments[2].operations[0]
assert isinstance(thermal_op.gate, cirq.KrausChannel)
thermal_choi = cirq.kraus_to_choi(cirq.kraus(thermal_op))
assert np.allclose(
thermal_choi,
[
[1, 0, 0, 9.99750031e-01],
[0, 2.49968753e-04, 0, 0],
[0, 0, 0, 0],
[9.99750031e-01, 0, 0, 9.99750031e-01],
],
)
# Pauli error for depol_op + thermal_op == total (0.001)
depol_pauli_err = 1 - cirq.qis.measures.entanglement_fidelity(depol_op)
thermal_pauli_err = 1 - cirq.qis.measures.entanglement_fidelity(thermal_op)
total_err = depol_pauli_err + thermal_pauli_err
assert np.isclose(total_err, SINGLE_QUBIT_ERROR)
def test_kraus_to_choi(kraus_operators, expected_choi):
"""Verifies that cirq.kraus_to_choi computes the correct Choi matrix."""
assert np.allclose(cirq.kraus_to_choi(kraus_operators), expected_choi)
def test_choi_to_kraus_atol():
"""Verifies that insignificant Kraus operators are omitted."""
choi = cirq.kraus_to_choi(cirq.kraus(cirq.phase_damp(1e-6)))
assert len(cirq.choi_to_kraus(choi, atol=1e-2)) == 1
assert len(cirq.choi_to_kraus(choi, atol=1e-4)) == 2
def test_choi_to_kraus_inverse_of_kraus_to_choi(choi):
"""Verifies that cirq.kraus_to_choi(cirq.choi_to_kraus(.)) is identity on Choi matrices."""
kraus = cirq.choi_to_kraus(choi)
recovered_choi = cirq.kraus_to_choi(kraus)
assert np.allclose(recovered_choi, choi)
