Quantum talk

Nguyen Ba An

André Chailloux

The goal of this talk is to present an introduction to quantum computing for non-specialists. I will first present the quantum computing model in order to have a first feel of what we can and cannot do with a quantum computer. Then I will present a few iconic quantum algorithms such as Grover’s algorithm and Shor’s algorithm. Finally, I will talk about perspectives relative to quantum-secure cryptography. During the talk, I will also briefly talk about error correction for quantum computation and quantum cryptography.

Olena Kovalenko, Vladyslav C. Usenko

We address the role of linear inter-mode cross talk in continuous-variable quantum key distribution in the most typical prepare-and-measure scenario. Considering coherent and well as squeezed signal states and either homodyne or heterodyne detection in the receiver station, we show how the cross talk deteriorates the secret key rate and robustness of the protocols to the channel noise. We show how optimization of the signal modulation can improve the performance of the protocols in the presence of cross talk and point out possibilities for further cross talk compensation.

Mara Beller

Vladyslav C. Usenko, Olena Kovalenko, Radim Filip

We address distribution of two-mode continuous-variable entanglement in the presence of linear cross-talk and channel imperfections. We show how cross-talk degrades entanglement and leads to necessity of optimization of the initial entangled resource. We suggest a method for compensating the cross-talk by a phase-flipping beamsplitter, which can optimally remove the negative effect of cross-talk once the modes undergo almost the same channel attenuation.

Anthony J. Killard