Experimental entanglement characterization of two-rebit states

We characterize entanglement subject to its definition over real and complex, composite quantum systems. In particular, a method is established assess correlations with respect selected number system, illuminating the deeply rooted, yet rarely discussed question of why states are described via complex numbers. With our experiment, we then realize two-photon polarization that entangled notion two rebits, comprising two-level systems At same time, generated separable qubits. Among other results, reconstruct best approximation in terms real-valued, local expansion show this yields an incomplete description data. Conversely, shown be fully decomposable tensor-product wave functions. Thereby, probe paradigms physics modern theoretical tools experimental platforms relevant for applications information science technology connected fundamentals nature.