Multi-photon Entanglement And Its Application

Recent advances in quantum information processing have enabled practical applications of quantum mechanics in various fields such as cryptography, computation, and metrology. Most of these applications use photons as carriers of quantum information. Therefore, engineering the quantum state of photons is essential for the realization of quantum information schemes.A practical technique to generate high-quality polarization entangled photon pairs is spontaneous parametric down conversion (SPDC) process. Furthermore, quantum information can be encoded in the polarization mode and spatial mode of photons by making use of hyper-entanglement. We experimentally demonstrated a hyper-entangled ten-qubit "Schrodinger cat" state. We experimentally realized a Controlled-NOT gate with four-photon six-qubit cluster states. We experimentally demonstrated measurement-based quantum computing beyond the cluster-state model. We experimentally implemented Bell inequality tests of four-photon six-qubit graph states. By using new ultra-bright sources of entangled photon pairs, the eight-photon "Schrodinger cat" state was created for the first time. Meanwhile, we designed the entangled photon source based on PPKTP crystal.