Bright soliton trains of trapped Bose-Einstein condensates

We variationally determine the dynamics of bright soliton trains composed of harmonically trapped Bose-Einstein condensates with attractive interatomic interactions. In particular, we obtain the interaction potential between two solitons. We also discuss the formation of soliton trains due to the quantum mechanical phase fluctuations of a one-dimensional condensate.     

Search for an 80 ms spontaneous fission activity in bombardments of 249Bk with 15N

A rotating drum system was used to search for an 80 ms spontaneous fission (sf) activity in the reaction of ¹⁵N with ²⁴⁹Bk. No such activity was found beyond a cross section limit of 0.5 nb. A sf activity with a half-life of 23 ± 2 ms and a maximum formation cross section of 19 ± 4 nb at 82 MeV was observed. The identity of this activity has not been determined.     

Fission of 232Th, 238U, 244Pu, 248Cm induced by Xe and Kr ions at coulomb barrier energies

Excitation functions and angular distributions have been measured for the fission of ²³²Th, ²³⁸U, ²⁴⁴Pu and ²⁴⁸Cm induced by ⁸⁶Kr and ¹³⁶Xe ions at energies in the vicinity of the Coulomb barrier. No large differences as a function of either target or projectile were found. These results suggest that the main process occuring is not Coulomb fission.     

Deformation of a trapped Fermi gas with unequal spin populations

The real-space densities of a polarized strongly interacting two-component Fermi gas of 6Li atoms reveal two low-temperature regimes, both with a fully paired core. At the lowest temperatures, the unpolarized core deforms with increasing polarization. Sharp boundaries between the core and the excess unpaired atoms are consistent with a phase separation driven by a first-order phase transition. In contrast, at higher temperatures the core does not deform but remains unpolarized up to a critical polarization. The boundaries are not sharp in this case, indicating a partially polarized shell between the core and the unpaired atoms. The temperature dependence is consistent with a tricritical point in the phase diagram.     

Photoassociation of a Bose-Einstein condensate near a Feshbach resonance

We measure the effect of a magnetic Feshbach resonance (FR) on the rate and light-induced frequency shift of a photoassociation resonance in ultracold 7Li. The photoassociation-induced loss-rate coefficient K_{p} depends strongly on magnetic field, varying by more than a factor of 10;{4} for fields near the FR. At sufficiently high laser intensities, K_{p} for a thermal gas decreases with increasing intensity, while saturation is observed for the first time in a Bose-Einstein condensate. The frequency shift is also strongly field dependent and exhibits an anomalous blueshift for fields just below the FR.     

RESTRICTED LIE ALGEBRAS WITH MAXIMAL 0-PIM

In this paper it is shown that the projective cover of the trivial irreducible module of a finite-dimensional solvable restricted Lie algebra is induced from the one dimensional trivial module of a maximal torus. As a consequence, the number of the isomorphism classes of irreducible modules with a fixed p-character for a finite-dimensional solvable restricted Lie algebra L is bounded above by p ^MT(L), where MT(L) denotes the maximal dimension of a torus in L. Finally, it is proved that in characteristic p > 3 the projective cover of the trivial irreducible L-module is induced from the one-dimensional trivial module of a torus of maximal dimension, only if L is solvable.     

Experimental studies of Bose-Einstein condensates in disorder

We review recent studies of the effects of disorder on an atomic Bose-Einstein condensate (BEC). We focus particularly on our own experiments with ⁷Li BECs in laser speckle. Both the interaction, which gives rise to the nonlinearity in a BEC, and the disorder can be tuned experimentally. This opens many opportunities to study the interplay of interaction and disorder in both condensed matter physics and nonlinear science.