Fig. 4

Quantum-state tomography of the ion–telecom-photon entangled states. Real and imaginary parts of the density matrices for: a the converted “bare” ion–photon entangled state still revealing the asymmetry in the diagonal elements (red bars) due to the asymmetric Clebsch–Gordan coefficients, b the converted ion–photon entangled state projected onto a Bell state by introducing polarization-dependent losses