New mechanism for spin relaxation during light scattering

Eugene P. Bashkin

Meng Wu, Cun‐Zheng Ning

Robert A. Cline, Joseph D. Miller, M. R. Matthews +1 more

We study spin relaxation of optically trapped atoms that is due to light scattering from the trap laser. We observe relaxation times greater than 2 s for ground-state hyperfine-level populations of 85Rb atoms trapped in an optical dipole force trap operating as much as 65 nm to the red of the D1 line. The measured relaxation rate can be more than 100 times slower than the atoms’ total spontaneous scatter rate from the trap laser. This enhancement in atomic ground-state lifetime is due to an interference effect in spontaneous Raman scattering far from atomic resonance.

Spencer Olson, Matthew L. Terraciano, Mark Bashkansky +1 more

Wolfgang Ketterle

Bose-Einstein condensed atomic gases are a new class of quantum fluids. They are produced by cooling a dilute atomic gas to nanokelvin temperatures using laser and evaporative cooling techniques. In this paper we review developments in Bose-Einstein condensation, emphasizing how this new quantum fluid has become a laboratory for the study of collisions at ultralow energy and of collective effects in light-atom and atom-atom interactions. Magnetic fields have been used to modify the scattering length for atomic collisions. Spinor condensates were created, with a spin structure determined by spin relaxation collisions and external magnetic fields. We have used light scattering to study collective excitations and observed superradiant light emission. Dissipation was studied by dragging a repulsive, blue-detuned laser beam through the fluid, as well as by inducing collisions between condensates.

Monika Schleier-Smith