ATOMIC TRAP cools by means of two different mechanisms. First, six laser beams (red) cool atoms, initially at room temperature, while corralling them toward the center of an evacuated glass box. Next, the laser beams are turned off, and the magnetic coils (copper) are energized. Current flowing through the coils generates a magnetic field that further confines most of the atoms while allowing the energetic ones to escape. Thus, the average energy of the remaining atoms decreases, making the sample colder and even more closely confined to the center of the trap. Ultimately, many of the atoms attain the lowest possible energy state allowed by quantum mechanics and become a single entity known as a Bose-Einstein condensate. Image: MICHAEL GOODMAN
Editor's Note: The main text of this article, originally published in the March 1998 issue of Scientific American, is being made available in light of the recent nomination of one of the authors, Carl Wieman, as associate director for science in the Office of Science and Technology Policy. Both authors won the Nobel Prize in Physics in 2001 for their discovery of the Bose-Einstein condensate. (Wolfgang Ketterle also shared the prize that year for his contributions.) The issue containing the full article with all artwork is available for purchase (PDF).
This article was originally published with the title The Bose-Einstein Condensate.