def test_kraus_application_dephasing():
p = 0.372
qam = PyQVM(
n_qubits=1,
quantum_simulator_type=ReferenceDensitySimulator,
post_gate_noise_probabilities={"dephasing": p},
)
rho = _random_1q_density()
qam.wf_simulator.density = rho
qam.execute_once(Program(I(0)))
final_density = np.array([[rho[0, 0], (1 - p) * rho[0, 1]],
[(1 - p) * rho[1, 0], rho[1, 1]]])
np.testing.assert_allclose(final_density, qam.wf_simulator.density)
def test_kraus_application_bitflip():
p = 0.372
qam = PyQVM(
n_qubits=1,
quantum_simulator_type=ReferenceDensitySimulator,
post_gate_noise_probabilities={"bit_flip": p},
)
initial_density = _random_1q_density()
qam.wf_simulator.density = initial_density
qam.execute_once(Program(I(0)))
final_density = (1 - p) * initial_density + p * qmats.X.dot(
initial_density).dot(qmats.X)
np.testing.assert_allclose(final_density, qam.wf_simulator.density)
def test_kraus_application_depolarizing():
p = 0.372
qam = PyQVM(
n_qubits=1,
quantum_simulator_type=ReferenceDensitySimulator,
post_gate_noise_probabilities={"depolarizing": p},
)
rho = _random_1q_density()
qam.wf_simulator.density = rho
qam.execute_once(Program(I(0)))
final_density = (1 - p) * rho + (p / 3) * (qmats.X.dot(rho).dot(qmats.X) +
qmats.Y.dot(rho).dot(qmats.Y) +
qmats.Z.dot(rho).dot(qmats.Z))
np.testing.assert_allclose(final_density, qam.wf_simulator.density)
def test_kraus_compound_T1T2_application():
p1 = 0.372
p2 = 0.45
qam = PyQVM(
n_qubits=1,
quantum_simulator_type=ReferenceDensitySimulator,
post_gate_noise_probabilities={
"relaxation": p1,
"dephasing": p2
},
)
rho = _random_1q_density()
qam.wf_simulator.density = rho
qam.execute_once(Program(I(0)))
final_density = np.array([
[rho[0, 0] + rho[1, 1] * p1, (1 - p2) * np.sqrt(1 - p1) * rho[0, 1]],
[(1 - p2) * np.sqrt(1 - p1) * rho[1, 0], (1 - p1) * rho[1, 1]],
])
np.testing.assert_allclose(final_density, qam.wf_simulator.density)
def test_multiqubit_decay_bellstate():
program = Program(RY(np.pi / 3, 0), CNOT(0, 1))
# commence manually dotting the above program
initial_density = np.zeros((4, 4), dtype=complex)
initial_density[0, 0] = 1.0
gate_time_1q = 50e-9
T1 = 30e-6
T2 = 15e-6
p1 = 1 - np.exp(-gate_time_1q / T1)
p2 = 1 - np.exp(-gate_time_1q / T2)
# RY
gate_1 = np.kron(np.eye(2), qmats.RY(np.pi / 3))
state = gate_1.dot(initial_density).dot(np.conj(gate_1).T)
for ii in range(2):
new_density = np.zeros_like(state)
for kop in qmats.relaxation_operators(p1):
operator = lifted_gate_matrix(matrix=kop,
qubit_inds=[ii],
n_qubits=2)
new_density += operator.dot(state).dot(np.conj(operator).T)
state = new_density
for ii in range(2):
new_density = np.zeros_like(state)
for kop in qmats.dephasing_operators(p2):
operator = lifted_gate_matrix(matrix=kop,
qubit_inds=[ii],
n_qubits=2)
new_density += operator.dot(state).dot(np.conj(operator).T)
state = new_density
# CNOT
# TODO: different 1q, 2q noise probabilities
cnot_01 = np.kron(qmats.I, qmats.P0) + np.kron(qmats.X, qmats.P1)
state = cnot_01.dot(state).dot(cnot_01.T)
gate_time_2q = 150e-9
p1 = 1 - np.exp(-gate_time_2q / T1)
p2 = 1 - np.exp(-gate_time_2q / T2)
for ii in range(2):
new_density = np.zeros_like(state)
for kop in qmats.relaxation_operators(p1):
operator = lifted_gate_matrix(matrix=kop,
qubit_inds=[ii],
n_qubits=2)
new_density += operator.dot(state).dot(np.conj(operator).T)
state = new_density
for ii in range(2):
new_density = np.zeros_like(state)
for kop in qmats.dephasing_operators(p2):
operator = lifted_gate_matrix(matrix=kop,
qubit_inds=[ii],
n_qubits=2)
new_density += operator.dot(state).dot(np.conj(operator).T)
state = new_density
qam = PyQVM(
n_qubits=2,
quantum_simulator_type=ReferenceDensitySimulator,
post_gate_noise_probabilities={
"relaxation": p1,
"dephasing": p2
},
)
qam.execute_once(program)
assert np.allclose(qam.wf_simulator.density, state)