THINK of an atom, and chances are you鈥檒l picture something that looks like a tiny solar system. You鈥檇 be wrong, but never fear: researchers have engineered an atom that looks just like you think it should.
When the atomic nucleus was discovered a century ago, the solar system analogy was obvious. The nucleus鈥檚 mass and charge would force electrons to circle it, just as the sun鈥檚 gravity holds orbiting planets. But quantum mechanics pooped the party, maintaining that electrons would smear out over large areas of space.
Now Tom Gallagher鈥檚 team at the University of Virginia in Charlottesville have trapped electrons and made them parade around a nucleus. Their inspiration came from Lagrange points 鈥� regions of space where gravity from different sources cancels out. They achieved a similar effect with an electron by using microwaves to counteract the force of the nucleus. This created an electron pocket like a Lagrange point, which they guided around the nucleus by rotating the microwave source (Physical Review Letters, vol 102, p 103001).
Advertisement
鈥淏esides being a beautiful piece of physics, it can really tell us a lot about how classical we can make quantum systems,鈥� says Carlos Stroud of the University of Rochester, New York.
