Abstract: Surprisingly enough, when two layers of electrons are close together they can take on properties reminiscent of both superfluid helium and superconducting Josephson junctions, and yet at the same time display a quantized Hall effect. This exotic state of affairs arises when Coulomb interactions join forces with a magnetic field to convert the bilayer electron gas into a weird collective state which may be equivalently viewed as a ferromagnet or a Bose condensate of excitons. In this talk I will discuss recent experiments on this fascinating system and speculate on what it might have still in store.
