PRODUCTION OF TWO OVERLAPPING BOSE-EINSTEIN CONDENSATES BY SYMPATHETIC COOLING

摘要: A new apparatus featuring a double magneto-optic trap and an Ioffe-type magnetic was used to create condensates of $2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms in either the $|F\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2,m\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2〉$ or $|F\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1,m\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}1〉$ spin states ${}^{87}$Rb. Overlapping two were also created using nearly lossless sympathetic cooling one state via thermal contact with other evaporatively cooled state. We observed that (i) scattering length $|1,\ensuremath{-}1〉$ is positive, (ii) rate constant for binary inelastic collisions between $2.2(9)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{3}/\mathrm{s}$, (iii) there repulsive interaction condensates. Similarities differences behaviors are observed.