• 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.

    Prof. Nicolas Gisin, Group Leader

Recent News

High-Precision Measurement of the Dzyaloshinsky-Moriya Interaction between Two Rare-Earth Ions in a Solid

Our recent paper published in Physical Review Letters has been highlighted as an Editor's Suggestion. There we report on a direct measurement of the pairwise antisymmetric exchange interaction between two rare earth ions in a solid-state material. This interaction is also known as Dzyaloshinsky-Moriya interaction (DMI) and is fundamentally important magnetic phenomena.

To study it we measure electron spin resonance on Nd$^{3+}$ doped single crystals of YVO$_4$ to directly reveal the pairwise anti-symmetric exchange interaction or DMI.








 

Light-Matter Micro-Macro Quantum Correlations

Quantum mechanics predicts microscopic phenomena with undeniable success. Nevertheless, current theoretical and experimental efforts still do not yield conclusive evidence that there is or is not a fundamental limitation on the possibility to observe quantum phenomena at the macroscopic scale.

In a recent publication in Physical Review Letters, we report on the generation of entangled state which involves the superposition of two macroscopically distinguishable solid-state components composed of several tens of atomic excitations. Our experiment is clearly demonstrating micro-macro light-matter entanglement.

 

Unfounded arXiv rejection of preprints

The Nature News highlights the discussion about arXiv screening policies which was triggered by the blog post written by Prof. Nicolas Gisin in December 2015. It describes the incident of an unsuccessful publication by two of his students on arXiv. The preprint was rejected by the moderators without reasonable justification. Professor Gisin indicates that such practice can have a big impact on young researchers’ careers.





 

Inspired by light 2015: Blog book

Popular article "Teleporting light" written by Felix Bussieres was selected to be a part of a book "Inspired by Light: Reflections from the International Year of Light 2015". It comprises various contributions to the blog devoted to the International Year of Light (IYL 2015) and was published by SPIE in January 2016.



 

Physics Today article on the photonic quantum memories

Communication through optical fibers has revolutionized the way people access information and has given rise to the network of connected computer nodes known as the internet. The photons that traverse the fibers are also nearly ideal carriers of quantum information. Today physicists are developing the technologies needed for a quantum version of the information network, which might be used for, among other applications, long-distance cryptography, distributed quantum computing, and remote sensing.

Quantum memories, another key building block, would act as the nodes where the photons—or rather, their quantum states—are temporarily stored while the system completes some other processing in the network. The quantum state of a photon can be transferred to a single trapped atom or to a bunch of atoms in a gas or solid and be stored for later release on demand. The spectacular progress in this field is discussed in our recent article published in Physics Today journal.