Physics is fascinating because of the intellectual excitement it provides and because of the applications it offers. In the Group of Applied Physics (GAP) at Geneva University we get our inspiration from both of these motivations. Optics, in this respect, has a privileged place. Indeed, in modern optics, experiments and theory progress hand-in-hand, and practical applications are close behind. Consequently, we can work both on conceptual issues and on applications. Moreover, it is a very good time for optics! The fascinating new insight about quantum mechanics brought about by recent quantum optics experiments on one side, and the tremendous development of optical communications on the other, illustrates our privileged position!
The American Research Council has recently declared optics as the technology of the 21st century. In contrast, a famous physicist, Michael Berry, has declared that the 21st century will be shaped by quantum physics, in a way similar to electrodynamics, which shaped the 20th century. Our position in GAP-Optique, at the crossroads between optics and quantum physics, ensures our participation to both challenges.
Congratulations to Dr. Christoph Clausen (pictured center of photo) for defending his doctoral thesis in February. The work involved the development of a source of entangled photons which could interact with solid state crystals acting as a quantum memory. This lead to a demonstration of entanglement transfer to the crystals followed by successful retrieval of the quantum information. This opens the door to a possible quantum repeater in the future. His thesis is available from our website.
This February, Professor Nicolas Gisin gave an open lecture at the University of Geneva, focusing on some of the extraordinary topics in his research. Starting off by talking about the implications of Newton's theory of universal gravitation, he led the audience to discover the fascinating phenomenon of quantum teleportation and the concept of non-locality. The lecture is now available for public viewing in French on the University of Geneva's Media Server.
Here is an excellent article written by Chris Lee on the Ars Technica website. It provides an overview and explanation of Quantum Cryptography for the general public, starting with the motivation for this technology; namely Quantum Computing, which could provide an efficient way of hacking classical encryption methods in the future. An interview with Professor Nicolas Gisin outlines the corresponding research work carried out in our group. In order to aid understanding, it includes a nice video explaining one version of Quantum Cryptography protocols, the so called BB84 protocol.
In our article published in the November issue of Nature Photonics, Nicolas Sangouard discusses a recent proposal for a quantum communication protocol without quantum memories, which could be an alternative approach for distributing quantum information over long distances. However, it is not without its own challenges, which are discussed and compared to the current work on quantum repeaters.