关键词: 纠缠测量, 超纠缠, 并发度

Abstract: We proposed a direct measurement schemes for the concurrences of photonic hyperentangled states based on quantum-dot-microcavity coupling system. The hyperentangled states were encoded in the polarization and spatial mode degrees of freedom (DOF) of photons. The schemes for entanglement measurement of both DOFs were constructed by error-heralded controlled-phase-flip gates through the single-photon input-output process of the quantum-dot-microcavity system. By transforming the concurrences into the detection probabilities of odd parity state, the schemes achieved efficient measurement of the concurrences of hyperentangled states. The schemes could not only independently measure the concurrence in each DOF, but also overcome the quantum operation distortions caused by cavity loss and imperfect coupling in traditional schemes. The research results show that the schemes have high experimental feasibility and robustness, providing a new approach for measuring hyperentangled states in quantum information processing.

Key words: entanglement measurement, hyperentanglement, concurrence