Observation of Interference between Two Bose Condensates

• Published in: Science (American Association for the Advancement of Science) 1997-01, Vol.275 (5300), p.637-641
• Main Authors: Andrews, M. R., Townsend, C. G., H.-J. Miesner, Durfee, D. S., Kurn, D. M., Ketterle, W.
• Format: Article
• Language: English
• Subjects: Argon; Atoms; Atoms & subatomic particles; Bosons; Classical and quantum physics: mechanics and fields; Condensed matter; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Fringe; Heat; Imaging; Ions; Kinetics; Laser beams; Laser power; Lasers; Magnetic fields; Matter waves; Observation; Phase coherent atomic ensembles; quantum condensation phenomena; Physics; Population Distribution; Quantum effects on the structure and dynamics of nondegenerate fluids (e.g., normal phase liquid 4he); Quantum fluids and solids; liquid and solid helium; Research Article
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.275.5300.637

Interference between two freely expanding Bose-Einstein condensates has been observed. Two condensates separated by ∼40 micrometers 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 ∼15 micrometers were observed after switching off the potential and letting the condensates expand for 40 milliseconds and overlap. This demonstrates that Bose condensed atoms are "laser-like"; that is, they are coherent and show long-range correlations. These results have direct implications for the atom laser and the Josephson effect for atoms.