Boojums in Rotating Two-Component Bose-Einstein Condensates

A boojum is a topological defect that can form only on the surface of an ordered medium such as superfluid $^3$He and liquid crystals. We study theoretically boojums appearing between two phases with different vortex structures in two-component BECs where the intracomponent interaction is repulsive in one phase and attractive in the other. The detailed structure of the boojums is revealed by investigating its density distribution, effective superflow vorticity and pseudospin texture.Comment: 4 pages, 4 figure

Si/Ge hole-tunneling double-barrier resonant tunneling diodes formed on sputtered flat Ge layers

We have demonstrated Si/Ge hole-tunneling double-barrier resonant tunneling diodes (RTDs) formed on flat Ge layers with a relaxation rate of 89% by our proposed method; in this method, the flat Ge layers can be directly formed on highly B-doped Si(001) substrates using our proposed sputter epitaxy method. The RTDs exhibit clear negative differential resistance effects in the static current–voltage (I–V) curves at room temperature. The quantized energy level estimation suggests that resonance peaks that appeared in the I–V curves are attributed to hole tunneling through the first heavy- and light-hole energy levels

Decay Properties of 266^{266}Bh and 262^{262}Db Produced in the 248^{248}Cm + 23^{23}Na Reaction

Decay properties of an isotope $^{266}$Bh and its daughter nucleus $^{262}$Db produced by the $^{248}$Cm($^{23}$Na, 5\textit{n}) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. $^{266}$Bh was clearly identified from the correlation of the known nuclide, $^{262}$Db. The obtained decay properties of $^{266}$Bh and $^{262}$Db are consistent with those observed in the $^{278}$113 chain, which provided further confirmation of the discovery of $^{278}$113.Comment: Accepted for publication in J. Phys. Soc. JPN., to be published in Vol.78 No.

Rotating BEC in an optical lattice in Uniformly frustrated Josephson Junction arrays regime: Vortex configuration formulation for ground state

We consider a rotating BEC in an optical lattices in a regime which can be mapped to the Joseohson junction arrays. In this regime, we formulate the ground state energy in terms of vortex configuration. This method give us the vortex lattice in the ground state in a natural way. We apply our result for an approximation scheme of the problem which we suppose that the coupling of the Josephson junctions are uniform. Application of method for ladder case presented and the results compared with Monte-Carlo method numerically.We discuss about restriction of method and suggest improvement for it.Comment: 6 pages, 7 figure