Nobel of Physics rewards Alain Aspect, pioneer of “second quantum revolution”

French is distinguished jointly with the American John Clauser and the Austrian Anton Zeilinger for the evidence of the entanglement of particles, paving the way for applications in quantum information.


For the French Alain Appearance, 75 years old, Director of Research Emeritity at the National Center for Scientific Research (CNRS) and professor at the Ecole Polytechnique, the question was not to know if he would have the Nobel Prize for physical, but when and with whom. The Swedish Academy therefore finally decided on Tuesday October 4. The French researcher shares the famous distinction with the American John Clauser, 79, and the Austrian Anton Zeilinger, 76 years old (University of Vienna), as a reward for “experiences with entangled photons, establishing the violation of Bell inequalities and paving the way to the science of quantum information “.

The price honors pioneers of what Alain aspect itself likes to baptize the “second quantum revolution”. This opens a window on a strange, microscopic world, at the same time as on unexpected and spectacular applications.

This quantum theory, developed during the interwar period, describes the world of matter, its particles, its atoms and its molecules. Its first revolution led to the invention of transistors, electronic chips, computers and mobile phones. She also gave birth to lasers or hard drives. It allows satellite geolocation thanks to high precision clocks.

It is based on at least two strangeness. On the one hand, on the fact that the particles are both waves and material objects, allowing them to pass for example by two places at the same time. And on the other hand, that the energies of these systems are not continuous but “quantified”, as if it were not possible to climb a slope only in jolts, by stairs or a scale. In this case, the metaphor describes the energy levels of these particles.

quantum entanglement

The second revolution is even stranger. Alain Aspect, then thesis student at the University of Orsay, showed in 1981 and 1982, by delicate experiences, now in all physics books, that she was very real. This is the possibility that, under certain conditions, two particles remain as linked by an invisible thread, even if they are separated by several kilometers. Impossible to consider the two elements of the pair as independent. The measurement of one of the properties of one of the members immediately influences the measure on its alter ego. It is quantum entanglement.

In 1964, the Briton John Bell had imagined a theoretical test to verify this prediction, in which Albert Einstein did not believe. This test aims to measure the state of the two particles created together simultaneously. Depending on whether this system is quantum or not, the correlations between the series of measurement results on each of the members of the pair are different; stronger in the quantum hypothesis than in the classic case.

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/Media reports.