By Peter Weiss
Extreme physical conditions have a way of bringing out the strangest behaviors that nature can muster. Just ask physicist John E. Thomas. Two years ago, he and his colleagues at Duke University in Durham, N.C., were working with intense lasers in a high-vacuum chamber at temperatures next to absolute zero. They were manipulating tiny clouds of lithium gas. When the scientists turned off the lasers, peculiar things began to happen. At first, the microscopic puff of lithium billowed out of the spot where the lasers had held it. But then, instead of expanding evenly in all directions, as any normal gas would, the lithium cloud morphed into a pancake.
That was the first glimpse of a new state of matter—a kind of ultrafrigid vapor—with the ponderous label “strongly interacting, degenerate Fermi gas.” Named after the Italian-born physicist Enrico Fermi, these aggregations of particles can behave, according to quantum mechanics, as if they’re a single entity.