# cirq.AsymmetricDepolarizingChannel¶

class cirq.AsymmetricDepolarizingChannel(p_x: float, p_y: float, p_z: float)[source]

A channel that depolarizes asymmetrically along different directions.

__init__(p_x: float, p_y: float, p_z: float) → None[source]

The asymmetric depolarizing channel.

This channel applies one of four disjoint possibilities: nothing (the
identity channel) or one of the three pauli gates. The disjoint
probabilities of the three gates are p_x, p_y, and p_z and the
identity is done with probability 1 - p_x - p_y - p_z. The supplied
probabilities must be valid probabilities and the sum p_x + p_y + p_z
must be a valid probability or else this constructor will raise a
ValueError.

This channel evolves a density matrix via

$$\rho \rightarrow (1 - p_x - p_y - p_z) \rho + p_x X \rho X + p_y Y \rho Y + p_z Z \rho Z$$

Parameters
• p_x – The probability that a Pauli X and no other gate occurs.

• p_y – The probability that a Pauli Y and no other gate occurs.

• p_z – The probability that a Pauli Z and no other gate occurs.

Raises

ValueError – if the args or the sum of args are not probabilities.