We report the first experimental study of sub-Doppler cooling in alkaline earth atoms (87Sr) enabled by the presence of nuclear spin-originated magnetic degeneracy in the atomic ground state. Sub-Doppler cooling in a sigma(+)-sigma(-) configuration is achieved despite the presence of multiple, closely spaced excited states. This surprising result is confirmed by an expanded multilevel theory of the radiative cooling force. Detailed investigations of system performance have shed new insights into (sigma(+)-sigma(-)) cooling dynamics and will likely play an important role in the future development of neutral atom-based optical frequency standards.

Using three-body recombination as the underlying process, we propose a method of coherently driving an atomic Bose-Einstein condensate (BEC) into a molecular BEC. Superradiantlike stimulation favors atom-to-molecule transitions when two atomic BECs collide at a resonant kinetic energy, the result being two molecular BEC clouds moving with well-defined velocities. Potential applications include the construction of a molecule laser.

Secondary circulations (SC) associated with hurricanes are traditionally regarded as small perturbations superimposed on the primary circulations (PC). The reason behind this treatment roots in an observation that the magnitude of the SC is about 10 orders of magnitude smaller than that of the PC. This serves a wide range of hurricane theories up until now with some considerable successes. Recently, Kieu (2004) proposes a revitalizing theory for the development of hurricanes in which the author is able to obtain a class of exact solutions of the primitive equations which shares some of the most important dynamical aspects with observations. According to this theory, the SC turns out to be particular important in determining the three-dimensional structure and time evolution of axisymmetric hurricanes. Kieu's theory, however, contains an infinite growth of the SC that all hurricane theories so far encounter in attempt to modeling the development of hurricanes. In this study, it will be shown that the infinite growth does not occur. In fact, the solution becomes stationary after a period of time and the SC is able to maintain itself without blowing exponentially with time if the nonlinear terms in the vertical momentum equation are included. In addition, the SC tends to force the peripheral convection to converge toward the center, and thus builds up a more concentric vortex with a typical hurricane eye structure. Some potential roles of SC in the formation of hurricane eyes are also discussed.