[14]. The atoms are confined in a magnetic trap that is produced by six permanent magnet cylinders. The magnets are arranged to produce a minimum at the trap center near which the field strength varies quadratically.

No abstract

We report the trapping of neutral atoms in a permanent magnet trap. Approximately 1X10 ground-state lithium atoms have been confined in a nonzero magnetic-field minimum produced by six permanent magnets in an Ioffe configuration. These atoms have a kinetic temperature of 1.1 mK and a peak density of approximately 3 X 10 cm. The trapped-atom lifetime is 240 s, limited by collisions with background gas. This trap provides an environment in which quantum-statistical effects, atomic collisions, and other ultralow-temperature phenomena can be studied.

Lithium atoms channeled in the nodes of an intense standing-wave radiation field are cooled to near the recoil limit by adiabatically reducing the radiation intensity. The final momentum distribution has a narrow component with a root-mean-squared momentum of 2h k in one dimension,~here A k is the momentum of a radiation-field photon. The data are compared with [3]. In this paper, we report cooling atoms to near the recoil limit in one dimension, using a method that requires only two atomic levels.An atom moving in a near-resonant standing-wave radiation field experiences a periodic, spatially varying potential energy due to the interaction of the induced electric dipole moment of the atom with the field. The atom can experience a force in the standing wave since the gradient of the potential energy may be nonzero. For a radiation field with frequency blue-detuned from resonance (i.e. , frequency greater than the atomic resonance frequency), the atoms will be attracted to the nodes of the standing wave. In this case, atoms whose maximum kinetic energy is less than the depth of the potential may be trapped around the nodes [4]. This In the experiment, shown schematically by Fig. 1, a collimated, thermal beam of lithium atoms is crossed at 90' by an intense, blue-detuned standing wave. The

An atomic beam of Li was transversely cooled using an intense standing-wave radiation field. A dramatic change in the transverse velocity distribution was observed. Structure in the resulting velocity distribution was found to be due to velocity-tuned multiphoton "Doppleron" resonances. The force due to seven-photon Fig. 2(a) depicts an atom moving with velocity v in a standing wave of frequency co in the laboratory frame. In the frame of the atom, shown in the lower part of Fig. 2(a)