215 research outputs found
Noncompact dynamical symmetry of a spin-orbit coupled oscillator
We explain the finite as well as infinite degeneracy in the spectrum of a
particular system of spin-1/2 fermions with spin-orbit coupling in three
spatial dimensions. Starting from a generalized Runge-Lenz vector, we
explicitly construct a complete set of symmetry operators, which span a
noncompact SO(3,2) algebra. The degeneracy of the physical spectrum only
involves a particular, infinite, so called singleton representation. In the
branch where orbital and spin angular momentum are aligned the full
representation appears, constituting a 3D analogue of Landau levels.
Anti-aligning the spin leads to a finite degeneracy due to a truncation of the
singleton representation. We conclude the paper by constructing the spectrum
generating algebra of the problem
Editorial for Special Edition, Digital Representations: Re-Using and Publishing Digital Qualitative Data
This collection of papers comprises five contributions with a social science or social historical perspective that present the current state of the art in the field of re-using and publishing digital qualitative data. The articles address the use of digital sources in qualitative research in both research and teaching, charting types of use over the past 10 years, and looking forward to emerging practices and methods, such as the promise and potential that technological innovations can bring to enable new ways of presenting and publishing qualitative research. Some of the papers make use of direct linking allowing the reader to explore ?live? data sources, offering an opportunity to see how research transparency might be operationalized in the presentation of qualitative findings and reporting. The papers reference major contributions to the literature and present stimulating debates on the topic and build on previously well-cited publications in which the editors have presented state-of- the-art articles on secondary analysis of qualitative data
A theory of topological edges and domain walls
We investigate domain walls between topologically ordered phases in two
spatial dimensions and present a simple but general framework from which their
degrees of freedom can be understood. The approach we present exploits the
results on topological symmetry breaking that we have introduced and presented
elsewhere. After summarizing the method, we work out predictions for the
spectrum of edge excitations and for the transport through edges in some
representative examples. These include domain walls between the Abelian and
non-Abelian topological phases of Kitaev's honeycomb lattice model in a
magnetic field, as well as recently proposed domain walls between spin
polarized and unpolarized non-Abelian fractional quantum Hall states at
different filling fractions.Comment: 4 pages, 1 figure, late
The speckled scallop, Argopecten circularis, in Aqua Hedionda Lagoon, San Diego County, California
Speckled scallops, Argopecten circularis (Sowerby, 1835), were sampled at Agua Hedionda Lagoon, Carlsbad, San Diego County from March 1984 to October 1986, to obtain basic life history data. Monthly samples of scallops were collected, measured, and released to obtain length frequency data for estimates of growth, life span, and spawning period. Subsamples of scallops were collected for determination of gonadal-somatic and adductor muscle-somatic indices.
In 1984 large concentrations of speckled scallops were found on the sand-silt bottom of the lagoon, closely associated with eelgrass, Zostra marina. During the course of the study the numbers of scallops declined, until their virtual disappearance at the end of 1986. Monthly length frequency plots from 24,375 scallop measurements indicate that this is a rapidly growing species with a short life span. Gonadal- and adductor muscle-somatic indices from subsamples of 1,714 scallops indicate first spawning at age one and a relationship between temperature and spawning.
Based on this study management recommendations are made for the speckled scallop. (39pp.
Revisiting Qualitative Data Reuse
Secondary analysis of qualitative data entails reusing data created from previous research projects for new purposes. Reuse provides an opportunity to study the raw materials of past research projects to gain methodological and substantive insights. In the past decade, use of the approach has grown rapidly in the United Kingdom to become sufficiently accepted that it must now be regarded as mainstream. Several factors explain this growth: the open data movement, research fundersâ and publishersâ policies supporting data sharing, and researchers seeing benefits from sharing resources, including data. Another factor enabling qualitative data reuse has been improved services and infrastructure that facilitate access to thousands of data collections. The UK Data Service is an example of a well-established facility; more recent has been the proliferation of repositories being established within universities. This article will provide evidence of the growth of data reuse in the United Kingdom and in Finland by presenting both data and case studies of reuse that illustrate the breadth and diversity of this maturing research method. We use two distinct data sources that quantify the scale, types, and trends of reuse of qualitative data: (a) downloads of archived data collections held at data repositories and (b) publication citations. Although the focus of this article is on the United Kingdom, some discussion of the international environment is provided, together with data and examples of reuse at the Finnish Social Science Data Archive. The conclusion summarizes the major findings, including some conjectures regarding what makes qualitative data attractive for reuse and sharing. </jats:p
Twenty-first Annual Bibliography, 2005 (Contemporary German Literature Collection)
Bibliography of contemporary German literature volumes added the previous year to Washington University Libraries\u27 Contemporary German Literature Collection. These acquisitions generally include novels, poetry, short story collections, essays, autobiographical works, and literary and cultural periodicals from publishers in Germany, Austria, and Switzerland. This Collection serves as the research arm for the Department of Germanic Languages and Literature\u27s Max Kade Center for Contemporary German Literature. This bibliography is compiled by Washington University\u27s Department of Germanic Languages and Literatures in cooperation with the University Libraries. See also Contemporary German Literature Collection and Max Kade Center for Contemporary German Literature
Particles in non-Abelian gauge potentials - Landau problem and insertion of non-Abelian flux
We study charged spin-1/2 particles in two dimensions, subject to a
perpendicular non-Abelian magnetic field. Specializing to a choice of vector
potential that is spatially constant but non-Abelian, we investigate the Landau
level spectrum in planar and spherical geometry, paying particular attention to
the role of the total angular momentum J = L +S. After this we show that the
adiabatic insertion of non-Abelian flux in a spin-polarized quantum Hall state
leads to the formation of charged spin-textures, which in the simplest cases
can be identified with quantum Hall Skyrmions.Comment: 24 pages, 10 figures (with corrected legends
Opportunities From the Digital Revolution: Implications for Researching, Publishing, and Consuming Qualitative Research
In the 1990s, the term 'online' research emerged as a new and vibrant suite of methods, focused on exploitation of sources not collected by traditional social science methods. Today, at least one part of the research life cycle is likely to be carried out 'online,' from data collection through to publishing. In this article, we seek to understand emergent modes of doing and reporting qualitative research 'online.' With a greater freedom now to term oneself a 'researcher,' what opportunities and problems do working with online data sources bring? We explore implications of emerging requirements to submit supporting data for social science journal articles and question whether these demands might disrupt the very nature of and identity of qualitative research. Finally, we examine more recent forms of publishing and communicating research that support outputs where data play an integral role in elucidating context and enhancing the reading experience
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