  We report the creation of a pair of Josephson junctions on a toroidal dilute
gas Bose-Einstein condensate (BEC), a configuration that is the cold atom
analog of the well-known dc superconducting quantum interference device
(SQUID). We observe Josephson effects, measure the critical current of the
junctions, and find dynamic behavior that is in good agreement with the simple
Josephson equations for a tunnel junction with the ideal sinusoidal
current-phase relation expected for the parameters of the experiment. The
junctions and toroidal trap are created with the painted potential, a
time-averaged optical dipole potential technique which will allow scaling to
more complex BEC circuit geometries than the single atom-SQUID case reported
here. Since rotation plays the same role in the atom SQUID as magnetic field
does in the dc SQUID magnetometer, the device has potential as a compact
rotation sensor.
