qml.NoiseModel

class NoiseModel(model_map, meas_map=None, **kwargs)

Bases: object

Builds a noise model based on the mappings of conditionals to callables that define noise operations using some optional metadata.

Parameters

• model_map (dict[BooleanFn -> Callable]) – Data for applying the gate errors as a {conditional: noise_fn} dictionary. The signature of noise_fn should be noise_fn(op: Operation, **kwargs) -> None, where op is the operation that the conditional evaluates and kwargs are the specified metadata arguments.

• meas_map (dict[BooleanFn -> Callable]) – Data for adding the readout errors similar to model_map. The signature of noise_fn must be noise_fn(mp: MeasurementProcess, **kwargs) -> None, where mp is the measurement process that the conditional evaluates and kwargs are the specified metadata arguments.

• **kwargs – Keyword arguments for specifying metadata related to the noise model.

Note

For each key-value pair of model_map and meas_map:

• The conditional should be either a function decorated with BooleanFn, a callable object built via constructor functions in the qml.noise module, or their bitwise combination.

• The definition of noise_fn(Union[op, mp], **kwargs) should have the operations in the same order in which they are to be queued for an operation op or measurement process mp, whenever the corresponding conditional evaluates to True.

• Each conditional in meas_map is evaluated on each measurement process in the order they are specified. The corresponding noise has to be added before the measurement, i.e., custom queing in noise_fn should not be done.

Example

# Set up the gate noise
c0 = qml.noise.op_eq(qml.PauliX) | qml.noise.op_eq(qml.PauliY)
c1 = qml.noise.op_eq(qml.Hadamard) & qml.noise.wires_in([0, 1])

def n0(op, **kwargs):
    qml.ThermalRelaxationError(0.4, kwargs["t1"], 0.2, 0.6, op.wires)
n1 = qml.noise.partial_wires(qml.AmplitudeDamping, 0.4)

# set up the readout noise
m0 = qml.noise.meas_eq(qml.expval) & qml.noise.wires_in([0, 1])
n2 = qml.noise.partial_wires(qml.PhaseFlip, 0.2)

# Set up noise model
noise_model = qml.NoiseModel({c0: n0}, meas_map={m0:n2}, t1=0.04)
noise_model += {c1: n1}

>>> noise_model
NoiseModel({
    OpEq(PauliX) | OpEq(PauliY): n0
    OpEq(Hadamard) & WiresIn([0, 1]): AmplitudeDamping(0.4, wires),
},
meas_map = {
    MeasEq(expval) & WiresIn([0, 1]): PhaseFlip(p=0.2)
}, t1=0.04)

Attributes

meas_map	Gives the measurement model for the noise model.
metadata	Gives the metadata for the noise model.
model_map	Gives the conditional model for the noise model.

meas_map

Gives the measurement model for the noise model.

metadata

Gives the metadata for the noise model.

model_map

Gives the conditional model for the noise model.

Methods

check_model(model)

Method to validate a {conditional -> noise_fn} map for constructing a noise model.

static check_model(model)

Method to validate a {conditional -> noise_fn} map for constructing a noise model.

code/api/pennylane.NoiseModel

 

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