cirq.PhaseDampingChannel

class cirq.PhaseDampingChannel(gamma: float)[source]

Dampen qubit phase.

This channel models phase damping which is the loss of quantum
information without the loss of energy.
__init__(gamma: float) → None[source]

The phase damping channel.

Construct a channel that enacts a phase damping constant gamma.

This channel evolves a density matrix via:

$$ \rho \rightarrow M_0 \rho M_0^\dagger + M_1 \rho M_1^\dagger $$
With:

$$ \begin{aligned} M_0 =& \begin{bmatrix} 1 & 0 \newline 0 & \sqrt{1 - \gamma} \end{bmatrix} \newline M_1 =& \begin{bmatrix} 0 & 0 \newline 0 & \sqrt{\gamma} \end{bmatrix} \end{aligned} $$

Parameters

gamma – The damping constant.

Raises

ValueError – if gamma is not a valid probability.