Bose–Einstein condensates (BECs) have opened yet another promising avenue of experimental research. This time, the road leads to an opportunity to study quantum phase transitions in a very clean and controlled manner. Specifically, researchers from the Max Planck Institute for Quantum Optics in Garching, Germany, and the University of Munich have shown that they can take a dilute gas of cold atoms from a super-fluid to an insulator—and back again—simply by varying the intensity of a laser beam. 1 Daniel Kleppner of MIT said it was “breathtaking” to witness a quantum fluid move back and forth between its superfluid and insulating phases.
Matthew Fisher, a condensed matter theorist from the University of California, Santa Barbara, was excited to see BECs getting into the regime in which interactions between the bosonic atoms are driving qualitatively new effects. He is eager for experimenters to gain similar control over degenerate fermions as well....
