Gaussian¶

`fidelity`	Returns the fidelity of two gaussian states.
`number_means`	Returns the photon number means vector given a Wigner covariance matrix and a means vector.
`purity`	Returns the purity of the state with the given covariance matrix.
`symplectic_eigenvals`	Returns the sympletic eigenspectrum of a covariance matrix.
`von_neumann_entropy`	Returns the Von Neumann entropy.

fidelity¶

mrmustard.physics.gaussian.fidelity(mu1, cov1, mu2, cov2)[source]¶

Returns the fidelity of two gaussian states.

Reference: arXiv:2102.05748, equations 95-99. Note that we compute the square of equation 98.

Parameters:

Returns:

The fidelity of the two states.

Return type:

float

mrmustard.physics.gaussian.number_means(cov, means)[source]¶

Returns the photon number means vector given a Wigner covariance matrix and a means vector.

Parameters:

Returns:

the photon number means vector

Return type:

Vector

mrmustard.physics.gaussian.purity(cov)[source]¶

Returns the purity of the state with the given covariance matrix.

mrmustard.physics.gaussian.symplectic_eigenvals(cov)[source]¶

Returns the sympletic eigenspectrum of a covariance matrix.

For a pure state, we expect the sympletic eigenvalues to be 1.

mrmustard.physics.gaussian.von_neumann_entropy(cov)[source]¶

Returns the Von Neumann entropy.

For a pure state, we expect the Von Neumann entropy to be 0.

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