Nonlocal biphoton generation in Werner state from a single semiconductor quantum dot

We demonstrate Werner-like polarization-entangled state generation disapproving local hidden variable theory from a single semiconductor quantum dot. By exploiting tomographic analysis with temporal gating, we find biphoton states are mapped on the Werner state, which is crucial for quantum information applications due to its versatile ramifications such as usefulness to teleportation. Observed time evolution of the biphoton state brings us systematic understanding on a relationship between tomographically reconstructed biphoton state and a set of parameters characterizing exciton state including fine-structure splitting and cross-dephasing time.