qiskit.providers.aer.noise.depolarizing_error

depolarizing_error(param, num_qubits, standard_gates=True)

Return a depolarizing quantum error channel.

The depolarizing channel is defined as:

$$E(ρ) = (1 - λ) ρ + λ \text{Tr}[ρ] \frac{I}{2^n}$$

with $0 \le λ \le 4^n / (4^n - 1)$

where $λ$ is the depolarizing error param and :math`n` is the number of qubits.

• If $λ = 0$ this is the identity channel $E(ρ) = ρ$

• If $λ = 1$ this is a completely depolarizing channel $E(ρ) = I / 2^n$

• If $λ = 4^n / (4^n - 1)$ this is a uniform Pauli error channel: $E(ρ) = \sum_j P_j ρ P_j / (4^n - 1)$ for all $P_j != I$.

Parameters

• param (double) – depolarizing error parameter.

• num_qubits (int) – the number of qubits for the error channel.

• standard_gates (bool) – if True return the operators as standard qobj Pauli gate instructions. If false return as unitary matrix qobj instructions. (Default: True)

Returns

The quantum error object.

Return type

QuantumError

Raises

NoiseError – If noise parameters are invalid.