QUROPE Quantum Information Processing and Communication in Europe

The program of the 6th winterschool on practical quantum communications deals with quantum cryptography, quantum computing and quantum repeaters. The goal of this event is to introduce this exciting topic in a relaxed and stimulating atmosphere to a general audience of physicists and computer scientists with little or no background in practical quantum communications. Special emphasis will be placed on practical aspects of quantum communications, such as the implementation of quantum key distribution systems and quantum repeaters, as well as concrete steps towards a quantum computer.

We demonstrate cooling of the motion of a single neutral atom confined by a dipole trap inside a high-finesse
optical resonator. Cooling of the vibrational motion results from electromagnetically induced transparency
(EIT)-like interference in an atomic \Lambda-type configuration, where one transition is strongly coupled to the cavity
mode and the other is driven by an external control laser. Good qualitative agreement with the theoretical
predictions is found for the explored parameter ranges. Further, we demonstrate EIT cooling of atoms in the

The paper, authored by F. Dolde, V. Bergholm, Y. Wang, I. Jakobi, S. Pezzagna, J. Meijer, P. Neumann, T. Schulte-Herbrueggen, J. Biamonte, and J. Wrachtrup, has been published on the 28th February 2014 on Nature Communications 5, 3371 (2014)

The paper, authored by S. Yang, L. Lehman, D. Poilblanc, K. Van Acoleyen, F. Verstraete, J. I. Cirac, and N. Schuch, has been published the 23rd January 2014 on Phys. Rev. Lett. 112, 036402

The paper, authored by Erwan Bimbard, Rajiv Boddeda, Nicolas Vitrant, Andrey Grankin, Valentina Parigi, Jovica Stanojevic, Alexei Ourjoumtsev, and Philippe Grangier, has been published on the 21st January 2014 on  PHYSICAL REVIEW LETTERS 112:3, 033601 (2014)

Identical particles and entanglement are both fundamental components of quantum mechanics. However, when identical particles are condensed in a single spatial mode, the standard notions of entanglement, based on clearly identifiable subsystems, break down. This has led many to conclude that such systems have limited value for quantum information tasks, compared to distinguishable particle systems.

We explore the feasibility of coherent control of excitonic dynamics in light harvesting complexes, analyzing the limits imposed by the open nature of these quantum systems. We establish feasible targets for phase and phase/amplitude control of the electronically excited state populations in the Fenna-Mathews-Olson (FMO) complex and analyze the robustness of this control with respect to orientational and energetic disorder, as well as decoherence arising from coupling to the protein environment.

The paper, authored by S. Yang, L. Lehman, D. Poilblanc, K. Van Acoleyen, F. Verstraete, J.I. Cirac, N. Schuch, has been published the 23rd January 2014 on Phys. Rev. Lett. 112, 036402 (2014)