Synthetic magnetic fields

An ultracold gas of atoms known as a Bose-Einstein condensate (BEC) is a nearly ideal system for creating new states of matter or studying many-body quantum phenomena at macroscopic scales. (For one example, see the article on Anderson localization by Alain Aspect and Massimo Inguscio in Physics Today, August 2009, page 30. The BEC’s charge neutrality, though, hinders its use as a probe of phenomena that arise from Lorentz forces on electrons in a magnetic field; magnetic fields produce only Zeeman shifts. Researchers at the Joint Quantum Institute, a collaboration of NIST and the University of Maryland, have now removed that limitation. The researchers, led by Ian Spielman, began with a BEC of roughly 250 000 rubidium-87 atoms held at 100 nK. By illuminating the atoms with a suitable pair of laser beams close to resonance, they imprinted an effective vector potential A* on the system. In...