Persistent currents in Bose gases confined in annular traps

We examine the problem of stability of persistent currents in a mixture of two Bose gases trapped in an annular potential. We evaluate the critical coupling for metastability in the transition from quasi-one to two-dimensional motion. We also evaluate the critical coupling for metastability in a mixture of two species as function of the population imbalance. The stability of the currents is shown to be sensitive to the deviation from one-dimensional motion.Comment: 6 pages, 4 figure

Phase diagram of a rapidly-rotating two-component Bose gas

We derive analytically the phase diagram of a two-component Bose gas confined in an anharmonic potential, which becomes exact and universal in the limit of weak interactions and small anharmonicity of the trapping potential. The transitions between the different phases, which consist of vortex states of single and multiple quantization, are all continuous because of the addition of the second component.Comment: 5 pages, 3 figure

Rotational properties of non-dipolar and dipolar Bose-Einstein condensates confined in annular potentials

We investigate the rotational response of both non-dipolar and dipolar Bose-Einstein condensates confined in an annular potential. For the non-dipolar case we identify certain critical rotational frequencies associated with the formation of vortices. For the dipolar case, assuming that the dipoles are aligned along some arbitrary and tunable direction, we study the same problem as a function of the orientation angle of the dipole moment of the atoms.Comment: 5 pages, 4 figure

Mixtures of Bose gases confined in concentrically coupled annular traps

A two-component Bose-Einstein condensate confined in an axially-symmetric potential with two local minima, resembling two concentric annular traps, is investigated. The system shows a number of quantum phase transitions that result from the competition between phase coexistence, and radial/azimuthal phase separation. The ground-state phase diagram, as well as the rotational properties, including the (meta)stability of currents in this system, are analysed.Comment: 6 pages, 5 figures, minor revision

Mobility, social status, and cooperative practices in the Sucupira Hiace Central Station, Santiago Island, Cape Verde

Cape Verde's main interurban public transport hubs, the Hiace minibus stations, provide a look into the patterns and processes of mobility, urbanization, and aspirations for modernity in the archipelago. In this article, we examine the history of Hiace vehicles, the regulations and rules governing their circulation, the social status of drivers as mobility providers, and everyday interactions between passengers and drivers in the central Hiace minibus station of Sucupira, on the island of Santiago. The formation of a cooperative unit inside the Hiace is at the core of these interactions, challenging the usual preconceptions about practices of “capturing passengers” in the station. The multiplicity of social relations embedded in the station and during the trips, we argue, reflects popular forms of self-organization and cooperation in traveling, as well as notions of mobility, social status, and culture that articulate everyday life for both collective transport drivers and working-class commuters in Cape Verdean society.info:eu-repo/semantics/submittedVersio

Electronic structure of few-electron concentric double quantum rings

The ground state structure of few-electron concentric double quantum rings is investigated within the local spin density approximation. Signatures of inter-ring coupling in the addition energy spectrum are identified and discussed. We show that the electronic configurations in these structures can be greatly modulated by the inter-ring distance: At short and long distances the low-lying electron states localize in the inner and outer rings, respectively, and the energy structure is essentially that of an isolated single quantum ring. However, at intermediate distances the electron states localized in the inner and the outer ring become quasi-degenerate and a rather entangled, strongly-correlated system is formed.Comment: 16 pages (preprint format), 6 figure

Optical response of two-dimensional few-electron concentric double quantum rings: A local-spin-density-functional theory study

We have investigated the dipole charge- and spin-density response of few-electron two-dimensional concentric nanorings as a function of the intensity of a perpendicularly applied magnetic field. We show that the dipole response displays signatures associated with the localization of electron states in the inner and outer ring favored by the perpendicularly applied magnetic field. Electron localization produces a more fragmented spectrum due to the appearance of additional edge excitations in the inner and outer ring.Comment: To be published in Physical Review

Spin-orbit-coupled Bose-Einstein-condensed atoms confined in annular potentials

A spin-orbit-coupled Bose-Einstein-condensed cloud of atoms confined in an annular trapping potential shows a variety of phases that we investigate in the present study. Starting with the non-interacting problem, the homogeneous phase that is present in an untrapped system is replaced by a sinusoidal density variation in the limit of a very narrow annulus. In the case of an untrapped system there is another phase with a striped-like density distribution, and its counterpart is also found in the limit of a very narrow annulus. As the width of the annulus increases, this picture persists qualitatively. Depending on the relative strength between the inter- and the intra-components, interactions either favor the striped phase, or suppress it, in which case either a homogeneous, or a sinusoidal-like phase appears. Interactions also give rise to novel solutions with a nonzero circulation.Comment: Final, slightly revised versio

Rotational properties of dipolar Bose-Einstein condensates confined in anisotropic harmonic potentials

We study the rotational properties of a dipolar Bose-Einstein condensate confined in a quasi-two- dimensional anisotropic trap, for an arbitrary orientation of the dipoles with respect to their plane of motion. Within the mean-field approximation we find that the lowest-energy state of the system depends strongly on the relative strength between the dipolar and the contact interactions, as well as on the size and the orientation of the dipoles, and the size and the orientation of the deformation of the trapping potential.Comment: 6 pages, 5 figure

Transcript expression of vesicular glutamate transporters in lumbar dorsal root ganglia and the spinal cord of mice – Effects of peripheral axotomy or hindpaw inflammation

Using specific riboprobes, we characterized the expression of vesicular glutamate transporter (VGLUT)1–VGLUT3 transcripts in lumbar 4–5 (L4–5) dorsal root ganglions (DRGs) and the thoracolumbar to lumbosacral spinal cord in male BALB/c mice after a 1- or 3-day hindpaw inflammation, or a 7-day sciatic nerve axotomy. Sham animals were also included. In sham and contralateral L4–5 DRGs of injured mice, VGLUT1-, VGLUT2- and VGLUT3 mRNAs were expressed in ∼45%, ∼69% or ∼17% of neuron profiles (NPs), respectively. VGLUT1 was expressed in large and medium-sized NPs, VGLUT2 in NPs of all sizes, and VGLUT3 in small and medium-sized NPs. In the spinal cord, VGLUT1 was restricted to a number of NPs at thoracolumbar and lumbar segments, in what appears to be the dorsal nucleus of Clarke, and in mid laminae III–IV. In contrast, VGLUT2 was present in numerous NPs at all analyzed spinal segments, except the lateral aspects of the ventral horns, especially at the lumbar enlargement, where it was virtually absent. VGLUT3 was detected in a discrete number of NPs in laminae III–IV of the dorsal horn. Axotomy resulted in a moderate decrease in the number of DRG NPs expressing VGLUT3, whereas VGLUT1 and VGLUT2 were unaffected. Likewise, the percentage of NPs expressing VGLUT transcripts remained unaltered after hindpaw inflammation, both in DRGs and the spinal cord. Altogether, these results confirm previous descriptions on VGLUTs expression in adult mice DRGs, with the exception of VGLUT1, whose protein expression was detected in a lower percentage of mouse DRG NPs. A detailed account on the location of neurons expressing VGLUTs transcripts in the adult mouse spinal cord is also presented. Finally, the lack of change in the number of neurons expressing VGLUT1 and VGLUT2 transcripts after axotomy, as compared to data on protein expression, suggests translational rather than transcriptional regulation of VGLUTs after injury.Fil: Malet, Mariana. Universidad Austral. Facultad de Ciencias Biomédicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vieytes, C. A.. Universidad Austral. Facultad de Ciencias Biomédicas; ArgentinaFil: Lundgren, K. H.. University of Cincinnati; Estados UnidosFil: Seal, R. P.. University of Pittsburgh; Estados UnidosFil: Tomasella, María Eugenia. Universidad Austral. Facultad de Ciencias Biomédicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Seroogy, K. B.. University of Cincinnati; Estados UnidosFil: Hökfelt, T.. Karolinska Huddinge Hospital. Karolinska Institutet; SueciaFil: Gebhart, G. F.. University of Pittsburgh; Estados UnidosFil: Brumovsky, Pablo Rodolfo. Universidad Austral. Facultad de Ciencias Biomédicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Pittsburgh; Estados Unido