qml.devices.default_gaussian.fock_expectation¶

fock_expectation(cov, mu, params, hbar=2.0)[source]¶

Calculates the expectation and variance of a Fock state probability.

Parameters

• cov (array) – $2N\times 2N$ covariance matrix

• mu (array) – length-$2N$ vector of means

• params (Sequence[int]) – the Fock state to return the expectation value for

• hbar (float) – (default 2) the value of $\hbar$ in the commutation relation $[\x,\p]=i\hbar$

Returns

the Fock state expectation and variance

Return type

tuple