Nicolas Gisin

Biography

Research

• The era of long distance quantum communication was effectively started by Nicolas Gisin’s experiment of 1995. in which a quantum cryptographic signal was transmitted at a distance of 23 km over a commercial optical fibre under Lake Geneva. Next, he co-invented the so-called Plug-&-Play and Coherent One Way configurations for quantum key distribution thanks to which world records distances of 67 km and 307 km could be demonstrated.
• In 1997, Nicolas Gisin and his group demonstrated Bell inequality violations at a distance of over 10 km. This was the first time when quantum non-locality was demonstrated outside the lab; the distance was increased by about three orders of magnitude with respect to all previous experiments. The picture of Lake Geneva with the marking of the 10 km optical fibre over which the photons travelled between the two villages of Bernex and Bellevue is one of the iconic images of the 1990s. This was followed by further experiments, ever strengthening the conclusion by excluding more and more sophisticated alternative models to quantum theory.
• In 2012, with colleagues, he proved that any possible explanation of quantum correlation based on some hidden influences possibly propagating at superluminal-but-finite speeds would activate signaling. This theoretical tour de force strengthened the tension between quantum non-locality and relativity to its utter most extreme.
• In the early 2000s he was first in demonstrating quantum teleportation over long distances. In the latter experiment the receiving photon was already hundreds of meters away when the Bell state measurement that triggers the teleportation process was performed.
• The previous breakthroughs would not have been possible without single-photon detectors compatible with telecommunication optical fibres. When Gisin entered the field such detectors did not exist. Today, thanks to Gisin and his group at the University of Geneva, single-photon detectors at telecom wavelengths are commercially available, with IDQ the uncontestable world leader.
• In 2001, with a student and two members of his University group, he founded ID Quantique, a spin-off company which quickly developed into the world leader in the field of quantum information and communication technologies. Our information based society rests on the possibility to communicate in confidence. This requires lots of random numbers and ways to distribute them among distant partners. IDQ is exploiting the quantum information technologies developed by Nicolas Gisin for providing solutions to precisely these needs. Several banks and other institutions, in several countries and continents, have now adopted this ultra-secure cryptographic technology.
• Nicolas Gisin’s work pushed optical fibre quantum communication almost to its limits. To go further one needs quantum memories and repeaters. His group invented an original quantum memory protocol using rare earth doped crystals and used it to demonstrate the first solid state quantum memory. Recently they entangled, first a photon with such a crystal, next two such crystals and finally teleportated a photonic qubit into a solid-state quantum memory over a distance of 25 km.
• Gisin’s demonstration of heralded entanglement between two macroscopic cm-long crystals is mind-boggling. How large can entangled objects be? And What does “macroscopic” mean? Nicolas Gisin addressed this deep question, providing original insights and performing a demonstration of entanglement between two optical modes in two spatially separated optical fibers, one of the modes being populated by about 500 photons.
• In 1964 John Bell discovered that nature is non-local, that is, actions in one location instantaneously have an effect in a distant region, in apparent contradiction of Einstein’s relativity according to which no signals can propagate faster than light. What Bell discovered is that non-local effects can nevertheless exist under the cover of quantum uncertainties. It is hard to overestimate the importance of this discovery for the entire field of physics. Arguably, it is probably on a par with Einstein's discovery of relativity itself. Yet for almost three decades, with a few notable exceptions, Bell’s discovery remained virtually unnoticed. Everything changed however with the work of Nicolas Gisin . Up to that moment it was known that non-locality arises in one extremely particular situation. Nicolas Gisin, however, showed that non-locality is generic: all pure quantum states generate non-locality. Gisin's theorem therefore puts non-locality at the core of physics.
• Schrödinger’s equation is a basic law of nature. Yet one may envisage that at a certain moment in the future novel discoveries may lead to its modification. The most natural such modification is introduction of non-linear terms. Another “Gisin theorem” states however that all deterministic nonlinear modifications of the Schrödinger equation necessarily activate quantum non-locality, leading to true violations of relativity.
• One of the most important characteristics of quantum information is the no-cloning theorem. Nicolas Gisin derived a bound on the fidelity of approximate quantum cloning from the relativistic no-signaling constraint.
• Nicolas Gisin contributed to relating non-locality to the security of quantum key distribution. This opened an entirely new field of research known as Device Independent Quantum Information Processing.
• In 1984 Nicolas Gisin’s proposed stochastic Schrödinger equations and his subsequent work together with Ian C. Percival is now widely used in the study of the dynamics of open quantum systems.
• Before becoming a quantum engineer, Nicolas Gisin worked as a classical telecommunication engineer, first in industry, next at the University. In particular he invented a technique to measure Polarization Mode Dispersion in optical fibers. This turned out to be an extremely important parameter of telecom fibers whose importance was initially underestimated. The technique was adopted as an international standard and was transferred to industry. Still today it is the most used technique to characterize PMD. Being both a classical and quantum engineer, he applied the abstract concepts of quantum weak values to the field of classical telecommunication networks.

  Awards

• Prize Dina Surdin, awarded by the Fondation Louis de Broglie, Paris, for his PhD thesis
• Product Performance Award, granted by Magazine PC Publishing for his work at the software company CPI
• Chosen by the to illustrate their ten posters on the Physics of the 20th century: his long distance quantum correlation experiment of 1998 illustrate the physics of the 1990 decade
• Selected by the MIT Technology Review as representative of one of the
• for the European IST-QuCom project for “excellence in collaborative research” awarded by the European Commission
• , Lausanne
• . Every 4 years the city of Geneva honours one Scientist living in Geneva.
• Fellow of the European Optical Society for “contribution to the foundation of quantum mechanics and its application”
• on “Quantum Correlations”
• for Research on Fundamental Issues in Quantum Mechanics and their Applications
• on “Macroscopic Entanglement in Crystals”
• Selected as a
• awarded by the . This is the highest Swiss prize for all sciences, awarded once per year to a single person
• , Measurement and Computing award, QCMC’14
• from the University of Pavia, Italy