Long-Distance Entanglement Distribution with Single-Photon Sources

By Nicolas Sangouard, C. Simon, J. Minář, H. Zbinden, Hugues de Riedmatten, Nicolas Gisin. 2007

147 citations recorded by the source corpus.

The entangled-state distribution over long distances is a challenging task due to the limited transmission efficiencies of optical fibers. To overcome this problem, quantum repeaters are likely to be required 1. The basic principle of quantum repeaters consists in decomposing the full distance into shorter elementary links. Quantum memories allow the creation of entanglement independently for each link. This entanglement can then be extended to the full distance using entanglement swapping. The protocol proposed here is similar to the well-known Duan-Lukin-Cirac-Zoller DLCZ scheme 2 and to its recent modification based on photon pairs and multimode memories P 2 M 3 3, in that entanglement for an elementary link is created by the detection of a single photon. However, both protocols rely on sources that create correlated pairs of excitations, namely, one atomic excitation and one photon in the case of the DLCZ scheme and two photons in the case of P 2 M 3 . These correlations allow one to establish entanglement between distant memories based on the detection of a photon which could have come from either of two remote sources. Our protocol uses single-photon sources, making it possible to eliminate errors due to two-pair emission events, which are unavoidable for Refs. 2,3. This leads to a significant improvement in the achievable entanglement distribution rate. Moreover, our scheme is compatible with the use of multimode memories 3 and spatial and frequency multiplexing 4 which promise additional speedups. We begin by recalling the basic principles of the P 2 M 3 protocol. The DLCZ protocol is equivalent for the purposes of the present discussion. The architecture of an elementary link is represented in Fig. 1a. The procedure to entangle two remote locations A and B requires one photon-pair source and one memory at each location. The pair sources are coherently excited such that each of them can emit a pair with a small probability p / 2, corresponding to the state 1+ p/2a † a † + b † b † + Op0;

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/c24d88c9e6e5a4ef83d174eb50ecc945c1913390

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Citations in the corpus

Quantum repeaters based on atomic ensembles and linear optics (2009, methodology): “11 of Ref.”
The security of practical quantum key distribution (2008, background): “But the tide may turn again in the near future, for applications in QKD with quantum repeaters (Sangouard et al., 2007). to produce pulses.”
Quantum interface between light and atomic ensembles (2008, methodology): “Several improvements of the protocol have been suggested (Chen et al., 2007b; Jiang et al., 2007; Sangouard et al., 2007b, 2008; Simon et al., 2007a; Zhao et al., 2007).”