Nobel Prize in Physics 2022 for Anton Zeilinger | the ILL congratulates

The Royal Swedish Academy of Sciences awarded the Nobel Prize in Physics 2022 jointly to Alain Aspect, John F. Clauser and Anton Zeilinger “for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science”. One of the laureates, Anton Zeilinger, started his scientific career with neutron experiments at the Atominstitut (Vienna, Austria) and the Institut Laue-Langevin (ILL).

Anton Zeilinger obtained the doctorate in 1971 for his work on "Neutron Depolarization in Dysprosium Single Crystals" under the supervision of Helmut Rauch. From 1974 to 1989, he worked half-time as a guest scientist at ILL, performing various experiments to test fundamental predictions of quantum mechanics. Here, Rauch and Zeilinger succeeded in a direct observation of fermion spin superposition, measured at the neutron interferometry station S18. In the same period, they demonstrated the sign change of the wave function of fermions under rotations of 360 degrees. These outstanding experiments marked the beginning of a long series of quantum experiments at the instrument S18 up to the present date.

After some time as visiting scientist at the Massachusetts Institute of Technology (M.I.T.), Anton Zeilinger held positions at TU Wien (Austria), TU München (Germany) and University of Innsbruck (Austria). During this period, he applied the concept of neutron interferometry to very cold neutrons aiming to win sensitivity due to a much longer wavelength, and to profit from different systematic effects compared to perfect crystal neutron interferometry at S18. The experiments took place at the ultra-cold and very cold neutron facility PF2. For this purpose, the beamline PF2/VCN was entirely rebuilt and equipped. The activity led to a precise measurement of the gravitational phase shift of neutron wave packets, and the experimental demonstration of the Scalar Neutron Aharonov-Bohm effect.

Anton Zeilinger’s research then turned towards experiments using mainly photons. The list of scientific highlights is long, ranging from the demonstration of the quantum teleportation of a photon, the developments of techniques for quantum entanglement, the teleportation of quantum states, important contributions to quantum information technology and quantum cryptography, to matter wave interferometry experiments similar to the ones with neutrons, but using atoms and even bucky balls.

The three laureates are awarded the Nobel Prize in Physics 2022 for their experiments with entangled quantum states of photons. Such systems are composed of several particles that are linked to each other in a way that is not intuitive to human perception. Theoretically, the particles cannot be described separately, they constitute a common quantum object: The measurement of one of the particles instantly influences the other, even if they are far apart.
The results were heavily debated in the past. Albert Einstein did not believe in this “spooky action at a distance”, but the experiments of Zeilinger, Aspect and Clauser have contradicted him: this strange entanglement of particles really exists.

The ILL congratulates Anton Zeilinger for all his scientific achievements in his long and outstanding career, along with Alain Aspect and John F. Clauser for their Nobel Prize in Physics 2022.