Nicolas Gisin (born 1952), Swiss physicist. Gisin joined the GAP (Group of Applied Physics) at the University of Geneva, Switzerland, in 1988. He has worked in quantum optics and optical sensors. His most famous work, in the 1990s and early 2000s, demonstrated the breakdown of causality in quantum physics. One of the strangest consequences of the quantum theories is that some quantum events can become entangled. Two particles will appear to be linked across space and time, with changes to one of the particles affecting the other one. This instantaneous effect is independent of time and space, showing that, for quantum events, effects can precede causes. Photographed in February 2003.