"Quantum Key Distribution"

Speaker: Dott. Daniele Cozzolino, Technical University of Denmark (DTU), Copenhagen

Proponent: Antigone Marino

Abstract

Quantum Key Distribution (QKD) provides an efficient means to exchange information in an unconditionally secure way. Conventional QKD protocols, mostly based on binary signal formats, encode one bit of information per photon, limiting the information efficiency. Contrariwise, QKD protocols using high-dimensional (HD) quantum states, namely protocols in which the information content carried by a photon is enlarged, are suitable for longer transmission distance and higher secret key rate transmission, being more robust to background noise and hacking attacks. Here, we propose and demonstrate the first HD-QKD protocol based on structured photons, i.e. a coherent superposition of different polarizations and orbital angular momentum (OAM) modes, propagating through a 1.2km long fiber.