Angular correlation and entanglement between a spin-polarization-resolved photoelectron and a polarization-resolved fluorescent photon

A theoretical study of the angular correlation and angular variation of entanglement between a photoelectron and a fluorescent photon in photoionization of atoms is provided. The formulation is developed for experiments where spin polarization of a photoelectron and polarization of the subsequent fluorescent photon are detected in a coincidence measurement. The applied formalism of parameterization of all polarization sensitivities of the detectors using Stokes parameters and of the use of statistical and efficiency tensors provides straightforward implementation for any experimental geometry. The framework is demonstrated in the case of calcium gamma(i) + [Ar] 4s(2) S-1(0) -> [Ar] 4p P-2(3/2) + epsilon(j) photoionization followed by [Ar] 4p P-2(3/2) -> [Ar] 4s S-2(1/2) + gamma radiative decay.