Non-Markovian Reactivation of Quantum Relays

Stefano Pirandola, Carlo Ottaviani, Christian S. Jacobsen, Gaetana Spedalieri, Samuel L. Braunstein, Tobias Gehring, Ulrik L. Andersen

Research output: Working paperPreprint


We consider a quantum relay which is used by two parties to perform several continuous-variable protocols: Entanglement swapping, distillation, quantum teleportation, and quantum key distribution. The theory of these protocols is extended to a non-Markovian model of decoherence characterized by correlated Gaussian noise. Even if bipartite entanglement is completely lost at the relay, we show that the various protocols can progressively be reactivated by the separable noise-correlations of the environment. In fact, above a critical amount, these correlations are able to restore the distribution of quadripartite entanglement, which can be localized into an exploitable bipartite form by the action of the relay. Our findings are confirmed by a proof-of-principle experiment and show the potential advantages of non-Markovian effects in a quantum network architecture.
Original languageEnglish
Number of pages7
Publication statusPublished - 27 May 2015


  • quant-ph
  • cond-mat.other
  • physics.optics

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