Abstract

A collection of ultracold atoms subject to a spatially periodic potential energy can exhibit behavior analogous to strongly-correlated electrons in a crystal lattice. This was shown recently by the experimental demonstration of the superfluid to Mott-insulator quantum phase transition for a three-dimensional optical lattice. An optical lattice consists of atoms subject to a periodic potential produced by interfering laser beams. The analogy between ultracold atoms in optical lattices and electrons in crystal lattices is manifestly a rich one. One interesting area in particular is the correspondence between the fractional quantum Hall effect for electrons in strong magnetic fields and rotating quantum gases. Here strongly-correlated effects can potentially be enhanced utilizing rotating optical lattices. Recently, we have also made a a proposal to extend the analogy to doped semiconductor materials. Lattice “defects” achieve behaviors similar to P-type and N-type semiconductor materials. Naturally the interest is to adjoin P-type and N-type atoms lattices to produce an atom diode, and then an NPN or PNP lattice “sandwich” to achieve bipolar transistor-like behavior for ultracold atoms. Such heterogeneous structures can indeed be made to mimic their electronic counterparts.

© 2007 Optical Society of America