OBSERVATION OF INTERFERENCE BETWEEN 2 BOSE CONDENSATES

Interference between two freely expanding Bose-Einstein condensates ha s been observed. Two condensates separated by similar to 40 micrometer s were created by evaporatively cooling sodium atoms in a double-well potential formed by magnetic and optical forces. High-contrast matter- wave interference fringes with a period of similar to 15 micrometers w ere observed after switching off the potential and letting the condens ates expand for 40 milliseconds and overlap. This demonstrates that Bo se condensed atoms are ''laser-like''; that is, they are coherent and show long-range correlations. These results have direct implications f or the atom laser and the Josephson effect for atoms.