Class NoiseModel

Inheritance Relationships

Derived Type

Class Documentation

class NoiseModel

Noise Model class This allows specification noise parameters for each quantum gate.

Subclassed by qb::QbNoiseModel

Public Types

enum class QubitConnectivity

Type of qubit connectivity.

Values:

enumerator AllToAll
enumerator Custom

Public Functions

NoiseModel() = default
NoiseModel(const nlohmann::json &js)

Construct a new Noise Model object from JSON.

Parameters

js – JSON object contains noise model parameters

NoiseModel(const NoiseProperties &noise_props)

Construct a new Noise Model object from noise properties.

Parameters

noise_props – Device noise properties

std::string to_json() const

Convert noise model to json string.

Returns

JSON string

std::vector<std::pair<int, int>> get_connectivity() const

Get the connectivity (pairs of connected qubits)

Returns

Connectivity as list of qubit index pairs

void add_gate_error(const NoiseChannel &noise_channel, const std::string &gate_name, const std::vector<size_t> &qubits)

Add a gate error channel for a gate operation.

Parameters

  • noise_channel – Noise channel to be associated with the gate

  • gate_name – Name of the gates

  • qubits – Qubit operands of the gate.

void add_qubit_connectivity(int q1, int q2)

Added connected qubit pair to the topology model.

Parameters

  • q1 – First qubit index

  • q2 – Second qubit index

void set_qubit_readout_error(size_t qubitIdx, const NoiseProperties::ReadoutError &ro_error)

Set the qubit readout error.

Parameters

  • qubitIdx – Qubit to set

  • ro_error – Readout error

Protected Functions

double decoherence_pauli_error(double t1, double tphi, double gate_time)

Calculate component of Pauli error caused by decoherence on a single qubit.

Parameters

  • t1 – T1 time

  • tphi – Tphi time

  • gate_time – Duration of the gate affected by this error.

Returns

Calculated Pauli error resulting from decoherence.

Protected Attributes

std::unordered_map<std::string, std::map<std::vector<size_t>, std::vector<NoiseChannel>>> m_noise_channels

Gate noise channel registry Map from gate name -> a map of qubit operands -> noise channel If the noise is uniform (qubit independent), use empty vector for qubit operands.

std::unordered_map<size_t, NoiseProperties::ReadoutError> m_readout_errors

Readout errors.

std::vector<std::pair<int, int>> m_qubit_topology

Qubit connectivity.

nlohmann::json m_qobj_noise_model

Noise model Json conforming to IBM Qiskit QObj schema if provided.