10,841 research outputs found
Texture control in a pseudospin Bose-Einstein condensate
We describe a wavefunction engineering approach to the formation of textures
in a two-component nonrotated Bose-Einstein condensate. By controlling the
phases of wavepackets that combine in a three-wave interference process, a
ballistically-expanding regular lattice-texture is generated, in which the
phases determine the component textures. A particular example is presented of a
lattice-texture composed of half-quantum vortices and spin-2 textures. We
demonstrate the lattice formation with numerical simulations of a viable
experiment, identifying the textures and relating their locations to a linear
theory of wavepacket interference.Comment: 4 pages, 5 figures, REVTeX4-
Statutory protection of freshwater flora and fauna
The aim of this paper is to summarize the present legislation aimed at protecting freshwater species in Britain, and briefly to review its effectiveness. Some areas have been deliberately omitted, such as fisheries legislation designed to conserve stocks, and the statutory protection of birds associated with fresh waters which forms a large subject area in its own right
Seed Reserves in Desert Soils
Soil and litter samples were collected from the playa, playa fringe and bajada zones of the Jornada Validation Site. These samples were analyzed for their seed content, special attention being paid to spatial distribution. At the time of sampling, there was little litter on the soil surface, and the litter contained only a small proportion of the total seeds present
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