def run_with_noise(circuit: Program, noise: float, shots: int) -> float:
"""Returns the expectation value of a circuit run several times with noise.
Args:
circuit: Quantum circuit as :class:`~pyquil.quil.Program`.
noise: Noise constant for depolarizing channel.
shots: Number of shots the circuit is run.
Returns:
expval: Expectation value.
"""
# apply depolarizing noise to all gates
kraus_ops = [
np.sqrt(1 - noise) * npI,
np.sqrt(noise / 3) * npX,
np.sqrt(noise / 3) * npY,
np.sqrt(noise / 3) * npZ,
]
circuit.define_noisy_gate("X", [0], append_kraus_to_gate(kraus_ops, npX))
circuit.define_noisy_gate("Y", [0], append_kraus_to_gate(kraus_ops, npY))
circuit.define_noisy_gate("Z", [0], append_kraus_to_gate(kraus_ops, npZ))
# set number of shots
circuit.wrap_in_numshots_loop(shots)
# we want to simulate noise, so we run without compiling
results = QVM.run(circuit)
expval = (results == [0]).sum() / shots
return expval
def dephased_rx_gate(phi, p=.1):
corrupted_rx = append_kraus_to_gate(
dephasing_kraus_map(p),
np.array([[np.cos(phi / 2), -1j * np.sin(phi / 2)],
[-1j * np.sin(phi / 2),
np.cos(phi / 2)]]))
return corrupted_rx
def amp_damp_i_gate(p=.1):
"""
Create amplitude damped Identity gate
"""
corrupted_i = append_kraus_to_gate(damping_kraus_map(p),
np.array([[1, 0], [0, 1]]))
return corrupted_i
def define_noisy_cliffords(p):
# We only use some of the clifford for this
noisy_clifford_gates = []
corrupted_H = append_kraus_to_gate(dephasing_kraus_map(p), 1/np.sqrt(2)*np.array([ [1, 1],[1, -1] ]) )
corrupted_X = append_kraus_to_gate(dephasing_kraus_map(p), np.array([[0, 1], [1, 0]]) )
corrupted_Y = append_kraus_to_gate(dephasing_kraus_map(p), np.array([[0, -1j], [1j, 0]]) )
corrupted_Z = append_kraus_to_gate(dephasing_kraus_map(p), np.array([[1, 0], [0, -1]]) )
noisy_clifford_gates.append(corrupted_H)
noisy_clifford_gates.append(corrupted_X)
noisy_clifford_gates.append(corrupted_Y)
noisy_clifford_gates.append(corrupted_Z)
return noisy_clifford_gates
def add_depolarizing_noise(pq: Program, noise: float) -> Program:
"""Returns a quantum program with depolarizing channel noise.
Args:
pq: Quantum program as :class:`~pyquil.quil.Program`.
noise: Noise constant for depolarizing channel.
Returns:
pq: Quantum program with added noise.
"""
pq = pq.copy()
# apply depolarizing noise to all gates
kraus_ops = [
np.sqrt(1 - noise) * npI,
np.sqrt(noise / 3) * npX,
np.sqrt(noise / 3) * npY,
np.sqrt(noise / 3) * npZ,
]
pq.define_noisy_gate("X", [0], append_kraus_to_gate(kraus_ops, npX))
pq.define_noisy_gate("Y", [0], append_kraus_to_gate(kraus_ops, npY))
pq.define_noisy_gate("Z", [0], append_kraus_to_gate(kraus_ops, npZ))
return pq
def pauli_noise_z_gate(p_I=.7, p_x=0.1, p_y=0.1, p_z=0.1):
corrupted_Z = append_kraus_to_gate(pauli_kraus_map([p_I, p_x, p_y, p_z]),
np.array([[1, 0], [0, -1]]))
return corrupted_Z
def dephased_i_gate(p=.1):
corrupted_iden = append_kraus_to_gate(dephasing_kraus_map(p),
np.array([[1, 0], [0, 1]]))
return corrupted_iden
def dephased_rz_gate(phi, p=.1):
corrupted_rz = append_kraus_to_gate(
dephasing_kraus_map(p),
np.array([[quil_cos(phi / 2) - 1j * np.sin(phi / 2), 0],
[0, np.cos(phi / 2) + 1j * np.sin(phi / 2)]]))
return corrupted_rz
