Two-way quantum cryptography at different wavelengths

Christian Weedbrook, Carlo Ottaviani, Stefano Pirandola

Research output: Contribution to journalArticlepeer-review


We study the security of two-way quantum cryptography at different wavelengths of the electromagnetic spectrum, from the optical range down to the microwave range. In particular, we consider a two-way quantum communication protocol where Gaussian-modulated thermal states are subject to random Gaussian displacements and finally homodyned. We show how its security threshold (in reverse reconciliation) is extremely robust with respect to the preparation noise and able to outperform the security thresholds of one-way protocols at any wavelength. As a result, improved security distances are now accessible for implementing quantum key distribution at the very challenging regime of infrared frequencies.
Original languageEnglish
Article number012309
JournalPhysical Review A
Volume 89
Issue number1
Publication statusPublished - 10 Jan 2014

Bibliographical note

8 pages, 6 figures


  • quant-ph

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