sf.physics.gaussian.CPTP¶
- mrmustard.physics.gaussian.CPTP(cov, means, X, Y, d, state_modes, transf_modes)[source]¶
Returns the cov matrix and means vector of a state after undergoing a CPTP channel.
Computed as
cov = X \cdot cov \cdot X^T + Y
andd = X \cdot means + d
.If the channel is single-mode,
modes
can containM
modes to apply the channel to, otherwise it must contain as many modes as the number of modes in the channel.- Parameters:
cov (Matrix) – covariance matrix
means (Vector) – means vector
X (Matrix) – the X matrix of the CPTP channel
Y (Matrix) – noise matrix of the CPTP channel
d (Vector) – displacement vector of the CPTP channel
state_modes (Sequence[int]) – modes the state is defined on
transf_modes (Sequence[int]) – modes on which the channel acts
- Returns:
the covariance matrix and the means vector of the state after the CPTP channel
- Return type:
Tuple[Matrix, Vector]