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Continuous Variable Quantum Cryptography - beating the 3 dB loss limit

Ch. Silberhorn·T. C. Ralph·N. Lütkenhaus·G. Leuchs
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Abstract

We demonstrate that secure quantum key distribution systems based on continuous variables implementations can operate beyond the apparent 3 dB loss limit that is implied by the beam splitting attack . The loss limit was established for standard minimum uncertainty states such as coherent states. We show that by an appropriate postselection mechanism we can enter a region where Eve's knowledge falls behind the information shared between Alice and Bob even in the presence of substantial losses.

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Ch. Silberhorn, T. C. Ralph, N. Lütkenhaus, G. Leuchs. 2002-08-19. Continuous Variable Quantum Cryptography - beating the 3 dB loss limit. https://doi.org/10.1103/physrevlett.89.167901

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