Alain Aspect, alive classic of quantum physics

Settling a 70-year-old dispute between Bohr and Einstein and breaking through a supposedly "insurmountable" barrier to absolute zero are some of the numerous achievements of Alain Aspect, recipient of the 2005 CNRS Gold Medal.

In 1985, together with Jean Dalibard and Christophe Salomon, Alain Aspect and Claude Cohen-Tannoudji launched a team to work on the laser cooling of atoms at Laboratoire Kastler Brossel (ENS). They pushed down atom cooling by breaking so-called “single photon limit,” getting down to one microkelvin—a mere millionth of a degree above absolute zero.

Ready for new challenges, Aspect set up an atom optics group at the Institut d'Optique at Orsay in 1992. Inspired by the 1995 revolutionary creation of the first gaseous Bose-Einstein condensate in the US, his team launched a program on atom lasers, a device promising exciting applications. In 2001, the team became the first to obtain a condensate of atoms of metastable helium, and opened a new chapter in “quantum atom optics”.
This multifaceted scientist is enthralled with his field: “The laser, the transistor and integrated circuits—and thus the computer—all have their origins in quantum physics, which also underlies the new field of quantum information.” So what's next for Aspect? “It's absurd to try to plan your life when you're a researcher,” he observes, “there is so much chance involved.” Indeed, where will the next quest lead this scientist, who is as hard to pin down as the particles of light he works with?

Matthieu Ravaud

1. J.S. Bell, “On the Einstein Podolsky Rosen Paradox” (1964). Paper reproduced in Speakable and unspeakable in quantum mechanics, Cambridge: Cambridge University Press, 2nd edition, 2004.

References: the main work of A. Aspect on superluminal propagation of the photons: Aspect A., Dalibard J., Roger G., Experimental Test of Bell's Inequalities Using Time-Varying Analysers. - Phys. Rev. Lett. 49, 25, (1982).

Alain Aspect's CV: CV d'Alain Aspect