Demonstration of neutral atom trapping with microwaves

Abstract

We demonstrate trapping of neutral Cs atoms by the magnetic dipole force due to a microwave field. The trap is formed in a spherical microwave cavity tuned near the ground state hyperfine transition (9.193 GHz). With a microwave power of 83 W, the trap is \ensuremath{\approxeq}0.1 mK deep. It is loaded with Cs atoms laser cooled to \ensuremath{\approxeq}4 \ensuremath{\mu}K. We observed oscillatory motion of atoms in the trap at frequencies of 1--3 Hz. This type of trap has certain advantages for achieving the conditions for Bose-Einstein condensation in hydrogen or the alkalis, because it can confine atoms predominantly in the lowest energy spin state.