Remote preparation of three-photon entangled states via single-photon measurement

Remote state preparation (RSP) provides an indirect way of transferring quantum information based on the nonlocal effect of quantum measurement. Although RSP has been demonstrated in recent years to remotely prepare multiphoton states, quantum measurement on the same number of additional photons was required, i.e., to prepare N-photon states via RSP, quantum measurement on the other N-photons was required, hence significantly limiting practicality and applicability of RSP. Here we report an experimental demonstration of remote preparation of three-photon entangled states by measuring only a single-photon entangled with the three photons. We further generalize our protocol to prepare multiphoton entangled states with arbitrary photon number and purity and to prepare a genuinely three-partite entangled state, both via single-photon measurement. As our RSP scheme relies on the nonlinearity induced by single-photon measurement, it enables quantum state engineering of multiphoton entangled states beyond the linear optical limit. Our results are expected to have significant impacts on quantum metrology and quantum information processing.