def noisy_moment(self, moment: 'cirq.Moment',
system_qubits: Sequence['cirq.Qid']) -> 'cirq.OP_TREE':
if self.is_virtual_moment(moment):
return moment
moments = []
if _homogeneous_moment_is_measurements(moment):
if self.decay_probs:
moments.append(
ops.Moment(
ops.AmplitudeDampingChannel(self.decay_probs[q])(q)
for q in system_qubits))
if self.bitflip_probs:
moments.append(
ops.Moment(
ops.BitFlipChannel(self.bitflip_probs[q])(q)
for q in system_qubits))
moments.append(moment)
return moments
else:
moments.append(moment)
if self.depol_probs:
gated_qubits = [
q for q in system_qubits
if moment.operates_on_single_qubit(q)
]
if gated_qubits:
moments.append(
ops.Moment(
ops.DepolarizingChannel(self.depol_probs[q])(q)
for q in gated_qubits))
return moments
def __init__(self, bitflip_prob: float):
"""A noise model with readout error.
Args:
bitflip_prob: Probability of a bit-flip during measurement.
"""
value.validate_probability(bitflip_prob, 'bitflip prob')
self.readout_noise_gate = ops.BitFlipChannel(bitflip_prob)
def __init__(self, depol_prob: float, bitflip_prob: float):
"""A depolarizing noise model with readout error.
Args:
depol_prob: Depolarizing probability.
bitflip_prob: Probability of a bit-flip during measurement.
"""
value.validate_probability(depol_prob, 'depol prob')
value.validate_probability(bitflip_prob, 'bitflip prob')
self.qubit_noise_gate = ops.DepolarizingChannel(depol_prob)
self.readout_noise_gate = ops.BitFlipChannel(bitflip_prob)
def __init__(self, bitflip_prob: float, prepend: bool = True):
"""A noise model with readout error.
Args:
bitflip_prob: Probability of a bit-flip during measurement.
prepend: If True, put noise before affected gates. Default: True.
"""
value.validate_probability(bitflip_prob, 'bitflip prob')
self.readout_noise_gate = ops.BitFlipChannel(bitflip_prob)
self._prepend = prepend
def __init__(self, depol_prob: float, bitflip_prob: float,
decay_prob: float):
"""A depolarizing noise model with damped readout error.
Args:
depol_prob: Depolarizing probability.
bitflip_prob: Probability of a bit-flip during measurement.
decay_prob: Probability of T1 decay during measurement.
Bitflip noise is applied first, then amplitude decay.
"""
value.validate_probability(depol_prob, 'depol prob')
value.validate_probability(bitflip_prob, 'bitflip prob')
value.validate_probability(decay_prob, 'decay_prob')
self.qubit_noise_gate = ops.DepolarizingChannel(depol_prob)
self.readout_noise_gate = ops.BitFlipChannel(bitflip_prob)
self.readout_decay_gate = ops.AmplitudeDampingChannel(decay_prob)
