depolarizing_error¶
- depolarizing_error(param, num_qubits, standard_gates=True)[source]¶
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
- Raises
NoiseError – If noise parameters are invalid.