| Citation | Aeppli is one of the world's leading condensed matter physicists, a winner of the American Physical Society's major Oliver Buckley Prize. He identified magnets with tunable quantum fluctuations using them to study the cross-over between the classical and quantum behaviour. His work demonstrated that magnetic quantum fluctuations could not be described by otherwise successful 20th century theory. His team showed such fluctuations as particularly strong in exotic superconductors, such as high transition temperature copper oxides, providing key evidence that quantum spin fluctuations, rather than the atomic vibrations of standard theory, are at the root of exotic superconductivity. |