Description
Distributing entanglement is pivotal for sharing quantum information over long distances via entanglement swapping protocols, enabling applications in communication, metrology, and computing. Entanglement swapping protocols consist of performing a Bell-state measurement (BSM) at a central station to share entanglement between two separate parties. Fully-optical entanglement swapping protocols require limited overhead compared to quantum-memory protocols. However, most implemented fully-optical protocols are built upon sharing polarization-entangled states and measuring two photons after a balanced BSM, which results in a linear scaling of the success rate with respect to the distance to the central station. Single-photon entangled states represent a promising alternative, exhibiting a square-root scaling of the success rate by heralding on one photon at the central station. In this work, we report heralding a single-photon entangled state and performing a tomographic reconstruction of the state using two weak-field homodyne measurements with click detectors and balanced beam splitters. We report a positive postselected concurrence of $C_{\text{pos}} = 0.462 \pm 0.005$, successfully signaling entanglement between the two parties after state reconstruction.
| I am the presenting author | Yes |
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