MACROSCOPIC QUANTUM INTERFERENCE FROM ATOMIC TUNNEL ARRAYS

Interference of atomic de Broglie waves tunneling from a vertical arra y of macroscopically populated traps has been observed, The traps were Located in the antinodes of an optical standing wave and were Loaded from a Bose-Einstein condensate. Tunneling was induced by acceleration due to gravity, and interference was observed as a train of falling p ulses of atoms. In the Limit of weak atomic interactions, the pulse fr equency is determined by the gravitational potential energy difference between adjacent potential wells. The effect is closely related to th e ac Josephson effect observed in superconducting electronic systems.