Noise Models

Functions

append_kraus_to_gate(kraus_ops, gate_matrix)	Follow a gate gate_matrix by a Kraus map described by kraus_ops.
pauli_kraus_map(probabilities)	Generate the Kraus operators corresponding to a pauli channel.
damping_kraus_map([p])	Generate the Kraus operators corresponding to an amplitude damping noise channel.
dephasing_kraus_map([p])	Generate the Kraus operators corresponding to a dephasing channel.
tensor_kraus_maps(k1, k2)	Generate the Kraus map corresponding to the composition of two maps on different qubits.
combine_kraus_maps(k1, k2)	Generate the Kraus map corresponding to the composition of two maps on the same qubits with k1 being applied to the state after k2.
damping_after_dephasing(T1, T2, gate_time)	Generate the Kraus map corresponding to the composition of a dephasing channel followed by an amplitude damping channel.
get_noisy_gate(gate_name, params)	Look up the numerical gate representation and a proposed ‘noisy’ name.
_decoherence_noise_model(gates[, T1, T2, …])	The default noise parameters
decoherence_noise_with_asymmetric_ro(gates)	Similar to _decoherence_noise_model(), but with asymmetric readout.
estimate_bitstring_probs(results)	Given an array of single shot results estimate the probability distribution over all bitstrings.
corrupt_bitstring_probs(p, …)	Given a 2d array of true bitstring probabilities (outer axis iterates over shots, inner axis over bits) and a list of assignment probability matrices (one for each bit in the readout, ordered like the inner axis of results) compute the corrupted probabilities.
bitstring_probs_to_z_moments(p)	Convert between bitstring probabilities and joint Z moment expectations.

Classes

class pyquil.noise.NoiseModel

Encapsulate the QPU noise model containing information about the noisy gates.

Variables:

• gates (Sequence[KrausModel]) – The tomographic estimates of all gates.
• assignment_probs (Dict[int,np.array]) – The single qubit readout assignment probability matrices keyed by qubit id.

Create new instance of _NoiseModel(gates, assignment_probs)

Methods

gates_by_name(name)	Return all defined noisy gates of a particular gate name.
to_dict()	Create a JSON serializable representation of the noise model.
from_dict(d)	Re-create the noise model from a dictionary representation.

class pyquil.noise.KrausModel

Encapsulate a single gate’s noise model.

Variables:

• gate (str) – The name of the gate.
• params (Sequence[float]) – Optional parameters for the gate.
• targets (Sequence[int]) – The target qubit ids.
• kraus_ops (Sequence[np.array]) – The Kraus operators (must be square complex numpy arrays).
• fidelity (float) – The average gate fidelity associated with the Kraus map relative to the ideal operation.

Create new instance of _KrausModel(gate, params, targets, kraus_ops, fidelity)

Methods

unpack_kraus_matrix(m)	Helper to optionally unpack a JSON compatible representation of a complex Kraus matrix.
unpack_kraus_matrix(m)	Helper to optionally unpack a JSON compatible representation of a complex Kraus matrix.
to_dict()	Create a dictionary representation of a KrausModel.
from_dict(d)	Recreate a KrausModel from the dictionary representation.