Textures of Spin-Orbit Coupled F=2 Spinor Bose Einstein Condensates

We study the textures of F=2 spinor Bose-Einstein condensates (BECs) with spin-orbit coupling (SOC) induced by a synthetic non-Abelian gauge field. On the basis of the analysis of the SOC energy and the numerical calculation of the Gross-Pitaevskii equation, we demonstrate that the textures originate from the helical modulation of the order parameter (OP) due to the SOC. In particular, the cyclic OP consists of two-dimensional lattice textures, such as the hexagonal lattice and the 1/3-vortex lattice, commonly understandable as the two-dimensional network of the helical modulations.Comment: 5 pages, 5 figure

Structural evolution of the Ongul Islands, Lutzow-Holm Complex, East Antarctica

We describe outcrop-scale folds at ten localities in the Ongul Islands, including five localities where interference patterns of more than two stages of folding are observed, along with structural data summarized in stereogram. F_(m-1) are recognized as isoclinal to rootless folds with fold axes trending NNW-SSE. S_(m-1) is defined by orthopyroxene, hornblende and biotite aligned parallel to the compositional layering and as axial planar foliation in F_(m-1) folds, and is folded by tight F_m. F_m have axial traces that trend NNW-SSE and subvertical axial planes dipping ENE and striking NNW-SSE. Axial planar foliation S_m is defined by biotite and hornblende in the hinges of F_m. F_(m-1) axes typically trend parallel to F_m axes and can be discriminated only in areas showing interference patterns. F_(m+1) are gentle to open with axes trending approximately N-S. Boudinage formed before Dm and interboudin partitions are filled with orthopyroxene-bearing leucosome. Judging from minerals constituting D_(m-1) and D_m structures, D_(m-1) occurred under granulite-facies conditions and at least part of D_m probably under amphibolite-facies conditions

Timing of ductile deformation and peak metamorphism in Skallevikshalsen, Lutzow-Holm Complex, East Antarctica

The geological structures of Skallevikshalsen, Lutzow-Holm Complex, East Antarctica are mainly controlled by two stages of ductile deformation, D_(m-1) and D_m. The D_(m-1) stage is characterized by the development of isoclinal F_(m-1) folds with fold axes gently plunging ENE or SWS, and axial planes parallel to the compositional layering (S_(m-1)) of the metamorphic rocks. The D_m stage is characterized by the development of tight folds with axes parallel to F_(m-1) and almost vertical axial planes. An axial planar foliation, S_m, defined by the alignment of biotite and hornblende, is formed in the hinges of F_m folds. No change in direction of elongation took place between D_(m-1) and D_m. Microstructural study and field observations show that a stretching lineation on S_(m-1) defined by the alignment of sillimanite was formed during D_(m-1). The alignment of sillimanite inclusions in garnet rims probably corresponds to an older schistosity formed during D_(m-2), which had a different orientation of principal strain axes than those of D_(m-1) and D_m. Peak metamorphic mineral assemblages are preserved in garnet cores, and their formation is considered to predate D_(m-2). Absence of the alignment of inclusions in garnet cores suggests that peak metamorphism was attained under conditions without strong deformation

Structural analysis of the Lutzow-Holm Complex in Akarui Point, East Antarctica, and overview of the complex

Two phases of major deformation are responsible for the dominant structures at Akarui Point, Prince Olav Coast, East Antarctica. The first phase, referred to as D_(m-1), is associated with the formation of foliation defined by biotite and hornblende aligned sub-parallel to compositional layering. The foliation is locally parallel to the axial planes of isoclinal and intrafolial folds of gneissic layers. Boudins are present with long axes subparallel to the axes of F_(m-1) folds. A second phase of deformation, denoted as D_m, produced a crenulation lineation and axial planar foliation that trends NW-SE throughout the area. This foliation is parallel to the axial plane of the large-scale Akarui Point Synform, which has a fold axis plunging gently SE, suggesting that the Akarui Point Synform formed during D_m. A locally-developed third phase of deformation (D_(m+1)) produced gentle folding of S_(m-1) and S_m. Chemical compositions of biotite grains that define S_(m-1) and S_m are similar. Migmatite shows close associations with D_(m-1) and D_m structures. This suggests that both phases of deformation were contemporaneous with high-grade metamorphism. Compilation of structural data in other areas reveals that D_(m-1) and D_m controlled dominant structures of the Lutzow-Holm Complex. Several folding events after D_m may be responsible for differing orientations of D_m structures between localities

Speciation and chromosomal rearrangements in the Australian Morabine Grasshopper Vandiemenella viatica species group

Recent theoretical developments have led to a renewed interest in the potential role of chromosomal rearrangements in speciation. Australian morabine grasshoppers (genus Vandiemenella, viatica species group) provide an excellent study system to test this potential role, because they show extensive chromosomal variation: 12 chromosomal races/species with parapatric distributions. The research in this thesis involves the application of molecular genetic analyses to examine patterns of gene introgression among chromosomal races of Vandiemenella at three different spatial scales: local-scale hybrid zone analysis, island-scale phylogeography, and continental-scale phylogeography. The aims of these multi-scale analyses are to investigate whether chromosomal races represent genetically distinct taxa with limited gene flow, and to infer the historical biogeography of Vandiemenella and evolutionary origins of their parapatric distributions. Karyotype and 11 nuclear markers revealed a remarkably narrow hybrid zone with substantial linkage disequilibrium and strong deficits of heterozygotes between the chromosome races P24(XY) and viatica17 on Kangaroo Island, suggesting that the zone is maintained by a balance between dispersal and selection against hybrids (tension zone). Selection that maintains the stable hybrid zone is unlikely to be operating only on loci linked to rearranged chromosomes. Island-scale and continental-scale phylogeography using multiple nuclear markers indicated that Vandiemenella chromosome races/species generally represent genetically distinct taxa with reduced gene flow between them. In contrast, analyses of a mitochondrial gene showed the presence of distinctive and geographically localised phylogroups that do not correspond with the distribution of the Vandiemenella taxa. These discordant population genetic patterns are likely to result from introgressive hybridization between the taxa and range expansions and contractions. Overall, our molecular analyses favour the allopatric mode of diversification for the evolution of Vandiemenella and do not support the stasipatric speciation model of White (1978). Patterns of genetic differentiation between the chromosomal races analysed at three different spatial scales show dynamic responses of the grasshoppers to past climatic fluctuations, leading to opportunities for long-term isolation and allopatric fixation of new chromosome variants and molecular mutations at many loci. Further analyses are necessary to assess potential roles of chromosomal rearrangements in facilitating diversification in Vandiemenella by reducing recombination within the rearranged chromosome segments

Semipolar {n[n¯]01} InGaN/GaN ridge quantum wells (n = 1−3) fabricated by a regrowth technique

Semipolar {n[n¯]01} InGaN/GaN quantum wells (QWs) (n = 1−3) are fabricated on top of GaN microstructures, which consist of semipolar {1Ī01} facets. Semipolar planes are obtained via regrowth of three-dimensional structures on (0001) GaN templates under controlled growth conditions. Compared to QWs on {1Ī01} facets, {n[n¯]01} ridge QWs show an intense emission at ∼ 440 nm. Time resolved photoluminescence reveals that the radiative lifetime of excitons in {n[n¯]01} InGaN ridge QWs at 13 K is 310 ps, which is comparable to that in {1Ī01} QWs. The estimated internal quantum efficiency at room temperature is as high as 57%