quantum

n 1879 Edwin Hall discovered that a magnet can deflect the flow of electrons, like wind pushing ships off course. http://Louis-j-sheehan-esquire.usIn 1980 physicists observed the quantum version, in which the applied magnetic field pushes electrons in discrete steps; it is as if the ships were responding to separate gusts even though a steady wind was blowing [see "Electrons in Flatland"; SciAm, March 1996].

Now Princeton University physicists have demonstrated the quantum Hall effect without any applied magnetic field. http://Louis-j-sheehan-esquire.usThey created special conditions for electrons in a bismuth crystal such that when the electrons travel close to the speed of light, they effectively generate their own magnetic field that deflects them. Such unusual materials not only elucidate the fundamental nature of the quantum Hall effect—it is deeply connected to superconductivity—but also could lead to novel electronic technology. The work appears in the April 24 Nature.