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Practical quantum repeater using intense coherent light
van Loock, Peter; Ladd, Thaddeus D.; Sanaka, Kaoru; Yamaguchi, Fumiko; Nemoto, Kae; Munro, William J.; Yamamoto, Yoshihisa
Keyword(s): quantum repeater; distributed entanglement; purification
Abstract: We describe a practical quantum repeater protocol for long-distance quantum communication. In this scheme, entanglement is created between the intermediate nodes of the quantum channel by using a weak dispersive light-matter interaction and distributing the outgoing intense coherent light pulses among the nodes. Noisy entangled pairs of electronic spin are then prepared with high success probability via homodyne detection including postselection. The local gates for entanglement purification and swapping are deterministic and measurement-free, based upon the same coherent-light resources and weak interactions as for the initial entanglement distribution. Finally, the entanglement is stored in a nuclear-spin-based quantum memory. Simulations of the system show qubit- communication rates approaching 100Hz and fidelities above 99% for reasonable local gate errors. Notes: Peter van Loock, Kae Nemoto and Yoshihisa Yamamoto, National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan. Thaddeus D. Ladd, Kaoru Sanaka and Fumiko Yamaguchi, Edward L.Ginzton Laboratory, Stanford University, Stanford, CA 94305, USA.
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