Noise — NoiseModel, QuantumError, NoiseOpType

API reference for noise modeling in pyqpanda3. The noise framework allows simulation of realistic quantum hardware by applying error channels to quantum operations.

NoiseModel

Manages a collection of quantum errors and readout errors applied during simulation.

Signature

python

class NoiseModel:
    def __init__() -> None

Methods

NoiseModel.is_enabled

python

is_enabled() -> bool

Check if the noise model contains any errors.

NoiseModel.add_read_out_error

python

add_read_out_error(probs: list[list[float]], qubit: int) -> None

Parameter	Type	Description
probs	`list[list[float]]`	Probabilities of readout error outcomes
qubit	`int`	Qubit index to apply readout error

NoiseModel.add_all_qubit_read_out_error

python

add_all_qubit_read_out_error(probs: list[list[float]]) -> None

Parameter	Type	Description
probs	`list[list[float]]`	Probabilities of readout error outcomes

NoiseModel.add_quantum_error (specific qubits)

python

add_quantum_error(error: QuantumError, gate_type: GateType, qubits: list[list[int]]) -> None
add_quantum_error(error: QuantumError, gate_types: list[GateType], qubits: list[list[int]]) -> None

Parameter	Type	Description
error	`QuantumError`	The quantum error to add
gate_type(s)	`GateType` or `list[GateType]`	Gate type(s) where error applies
qubits	`list[list[int]]`	Qubit index sets where error applies

NoiseModel.add_all_qubit_quantum_error

python

add_all_qubit_quantum_error(error: QuantumError, gate_type: GateType) -> None
add_all_qubit_quantum_error(error: QuantumError, gate_types: list[GateType]) -> None

Parameter	Type	Description
error	`QuantumError`	The quantum error to add
gate_type(s)	`GateType` or `list[GateType]`	Gate type(s) where error applies

Examples

python

from pyqpanda3.core import (
    NoiseModel, QuantumError, GateType,
    pauli_x_error, depolarizing_error,
    CPUQVM, QProg, H, CNOT, measure
)

# Create a noise model
model = NoiseModel()

# Add single-qubit depolarizing noise to all H gates
model.add_all_qubit_quantum_error(depolarizing_error(0.01), GateType.H)

# Add two-qubit Pauli-X noise to all CNOT gates
model.add_all_qubit_quantum_error(pauli_x_error(0.02), GateType.CNOT)

# Run with noise
qvm = CPUQVM()
prog = QProg()
prog << H(0) << CNOT(0, 1) << measure(0, 0) << measure(1, 1)
qvm.run(prog, 1000, model)
print(qvm.result().get_counts())

QuantumError

Represents a quantum error channel, specified either by Kraus matrices or Pauli error probabilities.

Signature

python

class QuantumError:
    def __init__() -> None
    def __init__(kraus_matrices: list[numpy.ndarray]) -> None
    def __init__(pauli_probs: dict[str, float]) -> None

Parameter	Type	Description
kraus_matrices	`list[numpy.ndarray]`	List of Kraus matrices
pauli_probs	`dict[str, float]`	Pauli error labels and probabilities (e.g., `{"X": 0.01}`)

Methods

QuantumError.tensor

python

tensor(quantum_error: QuantumError) -> QuantumError

Parameter	Type	Description
quantum_error	`QuantumError`	The quantum error to tensor with

Apply tensor product operation with another quantum error.

QuantumError.expand

python

expand(quantum_error: QuantumError) -> QuantumError

Parameter	Type	Description
quantum_error	`QuantumError`	The quantum error to expand with

Expand the error to a larger qubit system.

QuantumError.compose

python

compose(quantum_error: QuantumError) -> QuantumError

Parameter	Type	Description
quantum_error	`QuantumError`	The quantum error to compose with

Compose the error with another quantum error.

QuantumError.qubit_num

python

qubit_num() -> int

Number of qubits affected by the error.

QuantumError.error_type

python

error_type() -> NoiseOpType

The type of error representation (Kraus matrices or noise circuit).

QuantumError.error_circuit

python

error_circuit(qubits: list[int]) -> QCircuit

Parameter	Type	Description
qubits	`list[int]`	Qubit indices to apply the error circuit on

Circuit representation of the error.

QuantumError.error_karus

python

error_karus(qubits: list[int]) -> Karus

Parameter	Type	Description
qubits	`list[int]`	Qubit indices to get the Kraus matrices for

Kraus matrix representation of the error.

NoiseOpType

Enum for noise operation representation types.

Value	Description
`KARUS_MATRIICES`	Error represented by Kraus matrices
`NOISE`	Error represented by a noise circuit

Error Factory Functions

pauli_x_error

python

pauli_x_error(prob: float) -> QuantumError

Parameter	Type	Description
prob	`float`	Probability of Pauli-X error

Creates a single-qubit Pauli-X (bit-flip) error channel. With probability $p$ , an $X$ gate is applied.

E (ρ) = (1 - p) ρ + p X ρ X

pauli_y_error

python

pauli_y_error(prob: float) -> QuantumError

Creates a Pauli-Y (bit-phase-flip) error channel.

E (ρ) = (1 - p) ρ + p Y ρ Y

pauli_z_error

python

pauli_z_error(prob: float) -> QuantumError

Creates a Pauli-Z (phase-flip) error channel.

E (ρ) = (1 - p) ρ + p Z ρ Z

depolarizing_error

python

depolarizing_error(prob: float) -> QuantumError

Creates a depolarizing error channel. With probability $p$ , the state is replaced by the maximally mixed state $I / 2$ .

E (ρ) = (1 - p) ρ + p \frac{I}{2}

amplitude_damping_error

python

amplitude_damping_error(prob: float) -> QuantumError

Creates an amplitude damping (T1 relaxation) error channel modeling energy dissipation.

E (ρ) = E_{0} ρ E_{0}^{†} + E_{1} ρ E_{1}^{†}

where $E_{0} = [\begin{matrix} 1 & 0 \\ 0 & \sqrt{1 - γ} \end{matrix}]$ and $E_{1} = [\begin{matrix} 0 & \sqrt{γ} \\ 0 & 0 \end{matrix}]$ .

phase_damping_error

python

phase_damping_error(prob: float) -> QuantumError

Creates a phase damping (T2 dephasing) error channel modeling loss of phase coherence.

E (ρ) = [\begin{matrix} ρ_{00} & (1 - λ) ρ_{01} \\ (1 - λ) ρ_{10} & ρ_{11} \end{matrix}]

decoherence_error

python

decoherence_error(T1: float, T2: float, time_param: float) -> QuantumError

Parameter	Type	Description
T1	`float`	T1 (amplitude damping) relaxation time
T2	`float`	T2 (phase damping) dephasing time
time_param	`float`	Gate operation time

Creates a combined decoherence error modeling both T1 (amplitude damping) and T2 (phase damping) processes.

Noise — NoiseModel, QuantumError, NoiseOpType ​

NoiseModel ​

Signature ​

Methods ​

NoiseModel.is_enabled ​

NoiseModel.add_read_out_error ​

NoiseModel.add_all_qubit_read_out_error ​

NoiseModel.add_quantum_error (specific qubits) ​

NoiseModel.add_all_qubit_quantum_error ​

Examples ​

QuantumError ​

Signature ​

Methods ​

QuantumError.tensor ​

QuantumError.expand ​

QuantumError.compose ​

QuantumError.qubit_num ​

QuantumError.error_type ​

QuantumError.error_circuit ​

QuantumError.error_karus ​

NoiseOpType ​

Error Factory Functions ​

pauli_x_error ​

pauli_y_error ​

pauli_z_error ​

depolarizing_error ​

amplitude_damping_error ​

phase_damping_error ​

decoherence_error ​

See Also ​

Noise — NoiseModel, QuantumError, NoiseOpType

NoiseModel

Signature

Methods

NoiseModel.is_enabled

NoiseModel.add_read_out_error

NoiseModel.add_all_qubit_read_out_error

NoiseModel.add_quantum_error (specific qubits)

NoiseModel.add_all_qubit_quantum_error

Examples

QuantumError

Signature

Methods

QuantumError.tensor

QuantumError.expand

QuantumError.compose

QuantumError.qubit_num

QuantumError.error_type

QuantumError.error_circuit

QuantumError.error_karus

NoiseOpType

Error Factory Functions

pauli_x_error

pauli_y_error

pauli_z_error

depolarizing_error

amplitude_damping_error

phase_damping_error

decoherence_error

See Also