In the absence of quantum repeaters, quantum communication proved to be nearly impossible across optical fibers longer than greater than or similar to 20 km due to the drop of transmissivity below the critical threshold of 1/2. However, if the signals fed into the fiber are separated by a sufficiently short time interval, memory effects must be taken into account. In this Letter, we show that by properly accounting for these effects it is possible to devise schemes that enable unassisted quantum communication across arbitrarily long optical fibers at a fixed positive qubit transmission rate. We also demonstrate how to achieve entanglement-assisted communication over arbitrarily long distances at a rate of the same order of the maximum achievable in the unassisted noiseless case.

Restoring Quantum Communication Efficiency over High Loss Optical Fibers

Francesco Anna Mele
;
Ludovico Lami
Supervision
;
Vittorio Giovannetti
Supervision
2022

Abstract

In the absence of quantum repeaters, quantum communication proved to be nearly impossible across optical fibers longer than greater than or similar to 20 km due to the drop of transmissivity below the critical threshold of 1/2. However, if the signals fed into the fiber are separated by a sufficiently short time interval, memory effects must be taken into account. In this Letter, we show that by properly accounting for these effects it is possible to devise schemes that enable unassisted quantum communication across arbitrarily long optical fibers at a fixed positive qubit transmission rate. We also demonstrate how to achieve entanglement-assisted communication over arbitrarily long distances at a rate of the same order of the maximum achievable in the unassisted noiseless case.
2022
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
Open quantum systems; Decoherence; Quantum channels; Quantum communication; Quantum entanglement; Quantum information processing with continuous variables; Quantum information theory; Quantum repeaters
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/127003
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