Surpassing the repeaterless bound with a photon-number encoded measurement-device-independent quantum key distribution protocol

Abstract

Decoherence is detrimental to quantum key distribution (QKD) over large distances. One of the proposed solutions is to use quantum repeaters, which divide the total distance between the users into smaller segments to minimise the effects of the losses in the channel. Here we introduce a measurement-device-independent protocol which uses high-dimensional states prepared by two distant trusted parties and a coherent total photon number detection for the entanglement swapping measurement at the repeater station. We present an experimentally feasible protocol that can be implemented with current technology as the required states reduce down to the single-photon level over large distances. This protocol outperforms the existing measurement-device-independent and twin-field QKD protocols by achieving better key rates in general and higher transmission distance in total when experimental imperfections are considered. It also surpasses the fundamental limit of the repeaterless bound at a much shorter transmission distance in comparison to the existing TF-QKD protocols.

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“…Quantum entanglement is one of the most studied aspects of quantum mechanics [1], as well as one of the most important resources in quantum information processing, as interests in this resource has been growing and utilized in various quantum technologies namely quantum computation and quantum teleportation [2][3][4][5][6][7][8][9][10]. Entanglement occurs when two or more objects become entangled and remain correlated despite their distance [11].…”

Entanglement Classification for Three-qubit Pure Quantum System using Special Linear Group under the SLOCC Protocol

“…To put it simply, an object's properties between two or more objects are dependent to each other. Over the years, quantum entanglement has sparked a massive interest of research in numerous fields namely quantum computing, quantum cryptography and quantum teleportation [5][6][7][8][9][10][11][12][13][14][15].…”