Entangled-State Time Multiplexing for Multiphoton Entanglement Generation

Abstract

Finding a path toward efficient multiphoton entanglement generation would boost both foundational studies and practical applications of quantum entanglement in e.g. quantum computation, metrology, and communication. The common approach has a notorious problem of exponentially decreasing success probability with increasing photon number, so another method is needed for scalability. This Letter presents a scheme for creating $2n$-photon entangled states with an exponential efficiency-enhancement factor of ${B}^{n\ensuremath{-}1}$ without spoiling the entanglement. Even with just the currently demonstrated multiplexing power, applying this method to state-of-the-art 12-photon states would yield an enhancement factor of 10${}^{4}$.