Single-shot deterministic entanglement between non-interacting systems with linear optics

Understand

Measurement-based heralded entanglement schemes have served as the primary link between physically separated qubits in most quantum information platforms.

• However, the impossibility of performing a deterministic Bell measurement with linear optics bounds the success rate of the standard protocols to at most 50%, which means that the entanglement of the unheralded state is zero.
• Here we show that the ability to perform feedback during the measurement process enables unit success probability in a single shot.
• Our primary feedback protocol, based on photon counting retains the same robustness as the standard Barrett-Kok scheme, while doubling the success probability even in the presence of loss.