mercurial.core.entanglement module

Entanglement measures: concurrence and logarithmic negativity (Section 29).

mercurial.core.entanglement.concurrence_mixed(density: ndarray) → float

mercurial.core.entanglement.concurrence_pure(state: ndarray) → float

mercurial.core.entanglement.logarithmic_negativity_covariance(cov: ndarray) → float

mercurial.core.entanglement.squeezed_state_concurrence(r: float = 0.5, theta: float = 0.0, nbar: float = 0.05) → float

Compute concurrence for a two‑mode squeezed state with thermal noise.

Parameters:

rfloat

Squeezing parameter.

thetafloat

Squeezing angle.

nbarfloat

Mean thermal photon number per mode.

Returns:

Cfloat

Concurrence (0 for separable, 1 for maximally entangled).