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Heralded amplification of path entangled quantum states

2017; IOP Publishing; Volume: 2; Issue: 2 Linguagem: Inglês

10.1088/2058-9565/aa70ad

2058-9565

Fernando Sabino Marques Monteiro, E. Verbanis, Valentina Caprara Vivoli, Anthony Martin, Nicolas Gisin, Hugo Zbinden, Rob Thew,

Quantum optics and atomic interactions

Device-independent quantum key distribution (DI-QKD) represents one of the most fascinating challenges in quantum communication, exploiting concepts of fundamental physics, namely Bell tests of nonlocality, to ensure the security of a communication link.This requires the loophole-free violation of a Bell inequality, which is intrinsically difficult due to losses in fibre optic transmission channels.Heralded photon amplification is a teleportation-based protocol that has been proposed as a means to overcome transmission loss for DI-QKD.Here we demonstrate heralded photon amplification for path entangled states and characterise the entanglement before and after loss by exploiting a recently developed displacement-based detection scheme.We demonstrate that by exploiting heralded photon amplification we are able to reliably maintain high fidelity entangled states over loss-equivalent distances of more than 50 km.