An electric-field-assisted magnetic trap for cold molecular evaporative cooling: Toward molecular Bose-Einstein condensation

Ultracold molecules provide fundamental new insights into molecular interaction dynamics in the quantum regime and represent a new platform for chemical physics where quantum behaviors play a dominant role in molecular interaction and dynamics. An electric-field-assisted magnetic trap for trapping and further evaporative cooling of cold molecules to ultracold regime is proposed utilizing the perturbation of the hyperfine levels in a mixed field, and the depth of the trap can be tuned by adjusting the assisted electric field rapidly. Thus, the evaporative cooling of 127I79Br molecules in the |F=4,MF=-4 > state of the rovibronic ground state is simulated. It shows that IBr molecules would be cooled from 26 mu K to 556nK within 598.9ms and eventually we would obtain a number of 4.27x104 molecules in a volume of 3.27x10-7cm3 with the number density of 1.30x1012cm-3. The Bose-Einstein condensation of the alkali diatomic molecules would probably be realized in the proposed trap if the present experimentally available samples are loaded.