The Gedankenexperimente of quantum mechanics become reality: On the 2012 Nobel Prize in Physics, awarded to Serge Haroche and David J. Wineland

Abstract

The development of quantum mechanics at the beginning of the 20th century constituted one of the greatest revolutions in the theoretical and experimental sciences as well as in philosophy, completely transforming the way we understand the world at both micro- and macroscales. In fact, as its founders pointed out, quantum mechanics is strongly counterintuitive to our classical way of thinking. To overcome this limitation, Erwin Schrödinger and Albert Einstein, among others, proposed a series of idealized experiments to illustrate the paradoxical behavior of quantum mechanics, with the best known being “Schrödinger’s cat” and the “EPR paradox” (Einstein-Podolsky-Rosen paradox). These thought experiments, referred to by the German Gedankenexperimente, made use of the superposition principle and the entanglement of quantum systems to show the strange properties of quantum mechanics. However, they were somehow ridiculous proposals since, as indicated by Schrödinger himself, we would never be able to manipulate individual particles. The 2012 Nobel Prize in Physics was awarded to Serge Haroche and David J. Wineland, who, with extremely sophisticated experimental devices, are able to trap and manipulate individual photons and ions, respectively, thus allowing the Gedankenexperimente proposed at the beginning of quantum mechanics to become reality. In addition, these experiments set the foundations for a new field of research, quantum information science, and for the development of new applications, such as atomic clocks with unprecedented accuracy. These developments have signaled the beginning of a second quantum revolution.

Keywords: quantum optics · quantum mechanics · cavity quantum electrodynamics · trapping and cooling of ions