Abstract

Following the first observations of Bose-Einstein condensation (BEC) in dilute atomic gases, there has been considerable interest in multiple condensates as a system of interpenetrating quantum fluids.^1-5 Most recently in our time averaged orbiting potential (TOP) trap, we have created coherent superpositions of condensates in the |F = 1, m_F = −1〉 and |F = 2, m_F = 1〉 hyperfine ground states of Rubidium-87. A coupling field connects the states of this two level system. Following evaporative cooling to BEC in the|1,−1) state, a short coupling pulse allows us to transfer an arbitrary proportion of the atoms into the upper |2, 1〉 state. In the first experiments with two component condensates, we have determined the ratio of the intraspecies scattering lengths for the two hyperfine states mentioned above;³ we have transferred half of the atoms to the upper |2, 1〉 state to investigate the dynamics of the two components’ separation;⁴ and we have found that, in the regions where they overlap, the two condensates retain a well defined phase even after the damping of their relative center of mass motion.⁵

© 1999 Optical Society of America