Is light wave or particle? This question was addressed during the “Lange Nacht der Forschung 2018” (Long Night of Research) on April 13 by scientists of the IQOQI Vienna of the Austrian Academy of Sciences. The Long Night of Research is the biggest public event in Austria for young people and adults who are interested in science and research. At Vienna’s Heldenplatz in the heart of the city three experiments – which were first presented at the art exhibition ”Documenta” in Germany in 2012 – were set up by the IQOQI. The aim was to provide visitors with a hands-on experience to make discoveries about the nature of light on their own.
Therefore, a fiber optic interferometer demonstrated interference effects which are only explainable by the wave properties of light. In contradiction to that, single-photon detectors measured light that passed through a 50:50 beam splitter, pointing out the particle properties of light as well as the randomness in quantum physics. Those two experiments demonstrated the wave-particle-duality of light, meaning that it is not possible to image light is either particle or wave. Rather one has to thing of it as being both at the same time. In a third experiment, polarizers were used to show the consequence of the measurement and demonstrate the collapse of the state.
The opportunity of watching and operating scientific state-of-the-art devices was highly appreciated and led to interesting discussions with visitors of all ages on further fundamental and advanced topics such as entanglement, quantum cryptography, quantum computers and other applications.
With a total of 30.000 visitors in Vienna IQOQI`s quantum physicists are looking forward to 2020, when the next Long Night of Research takes place, for continuing exchange of knowledge and sharing the fascination about entanglement and the quantum world with the public.
More impressions from the Long Night of Research at the website of the Academy