Philip Ball in Prospect:
There’s never been a better time to be a quantum physicist. The foundations of quantum theory were laid a century ago, but the subject is currently enjoying a renaissance. Modern experimental techniques make it possible to probe fundamental questions that were left hanging by the subject’s originators, such as Albert Einstein, Niels Bohr, Erwin Schrödinger and Werner Heisenberg. Now, we are not only grappling with the supposed weirdness of the quantum world, but also putting its paradoxical principles to practical use.
This is reflected in the fact that three physics Nobel prizes have been awarded since 1997 in the field of quantum optics, the most recent going this week to Serge Haroche of the Collège de France and the Ecole Normale Supérieure in Paris and David Wineland of the National Institute of Standards and Technology and the University of Colorado. It’s “quantum” because the work of these two scientists is concerned with examining the way atoms and other small particles are governed by quantum rules. And it’s “optics” because they use light to do it. Indeed, light is itself explained by quantum physics, being composed (as Einstein’s Nobel-winning work of 1905 showed) of packets of energy called photons. The word “quantum” was coined by Max Planck in 1900 to describe this discrete “graininess” of the world at the scale of atoms.