Description
Date depot: 7 novembre 2019
Titre: Quantum optics systems for long-distance cryptography and communication networks
Directrice de thèse:
Eleni DIAMANTI (LIP6)
Encadrante :
Valentina PARIGI (LKB)
Domaine scientifique: Sciences et technologies de l'information et de la communication
Thématique CNRS : Systèmes et réseaux
Resumé:
Quantum optics is an idea experimental platform for implementing quantum communica-tion protocols. In this context, encoding information into the quadrature components of the electromagnetic field – which is typically called continuous-variable (CV) encoding – is particularly appealing as it fits naturally with the quantum optics framework.
CV have been used successfully for the implementation of one of the most important applications in quantum information science, namely quantum key distribution (QKD), which allows two parties to share a secret key that can be subsequently used for message exchange, even in the presence of eavesdroppers with unlimited power. This is impossible by classical means. CV-QKD is particularly appealing from a practical point of view in that its implementation only requires off-the-shelf telecom components and in particular no photon counting.
The communication over terrestrial optical channels is inherently limited by losses. A great challenge in the field is therefore the possibility to extend the communication distance by exploiting either ground-to-satellite optical links or advanced quantum net-works exploiting entangled states that also have the capacity to offer advanced functionalities going further than the distribution of secret keys.
In this doctoral project, we propose to study the use of CV technology for long-distance quantum cryptography and communication applications. The work will be twofold. First, we will perform feasibility studies for CV-QKD in space taking into account parameters such as atmospheric turbulence, pointing and divergence errors, and fluctuations in transmission efficiency and noise, and their effect in the security analysis of the protocol, eventually leading towards the design of a laboratory prototype. Second, we will explore multimode quantum optics for the experimental generation of highly entangled CV states at telecom wavelength and their use for quantum communication applications.
Doctorant.e: Roman_Rodriguez Victor