1,388 research outputs found
Electrically and Magnetically Charged States and Particles in the 2+1-Dimensional Z_N-Higgs Gauge Model
Electrically as well as magnetically charged states are constructed in the
2+1-dimensional Euclidean Z_N-Higgs lattice gauge model, the former following
ideas of Fredenhagen and Marcu and the latter using duality transformations on
the algebra of observables. The existence of electrically and of magnetically
charged particles is also established. With this work we prepare the ground for
the constructive study of anyonic statistics of multiparticle scattering states
of electrically and magnetically charged particles in this model (work in
progress).Comment: 57 pages, Sfb 288 Preprint No. 109. To appear in Commun. Math. Phys.
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included. The LaTeX sources ou even hard copies can be required to the
authors at [email protected] or Freie Universitaet Berlin.
Institut fuer Theoretische Physik. Arnimallee 14. Berlin 14195 German
Localizability in de Sitter space
An analogue of the Newton-Wigner position operator is defined for a massive
neutral scalar field in de Sitter space. The one-particle subspace of the
theory, consisting of positive-energy solutions of the Klein-Gordon equation
selected by the Hadamard condition, is identified with an irreducible
representation of de Sitter group. Postulates of localizability analogous to
those written by Wightman for fields in Minkowski space are formulated on it,
and a unique solution is shown to exist. A simple expression for the
time-evolution of the operator is presented.Comment: Presentation improved; references adde
Abused women\u27s perspectives on the criminal justice system\u27s response to domestic violence.
In the last five years a number of studies have been conducted that have given abused women voice in the discussion about whether or not the criminal justice system (CJS) can be helpful to them. These studies have used a variety of methods and examined different questions, but they have not considered how women\u27s views of separate parts of the CJS come together in their perspectives about the system as a whole. The purpose of this study was to better understand battered women\u27s views about the criminal justice system (CJS), and how those views are integrated into complex perspectives for individual women. Q methodology was used. Fifty-eight abused and formally abused women were recruited to represent a broad range of experiences and perspectives. They sorted 72 statements about domestic violence and the CJS on a large template that ranged from strongly disagree to strongly agree. Principal component analysis with varimax rotation was performed and the resulting factors were analysed for meaning. A small number of women who represented each factor were interviewed to aid in this interpretation. Five perspectives were identified representing divergent views of the CJS: (1) Trust in the CJS; (2) Disappointment in the CJS; (3) Victims should have input into the CJS and be sure they want to use it; (4) The CJS cannot protect women and can make matters worse; and (5) The CJS should be used for her safety, for his rehabilitation, and for justice despite its problems. The perspectives that emerged are new in their complexity and in their substance. Overall, the emergence of multiple perspectives as opposed to one polarized perspective has theoretical, methodological, and applied implications for research and practice. The description of each of the perspectives expressed by the women in this study may also be useful in advising other women who hold similar perspectives.Dept. of Psychology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .B37. Source: Dissertation Abstracts International, Volume: 65-07, Section: B, page: 3770. Adviser: Charlene Senn. Thesis (Ph.D.)--University of Windsor (Canada), 2004
The Two-Point Function and the Effective Magnetic Field in Diluted Ising Models on the Cayley Tree
Some results on the two-point function and on the analytic structure of the
momenta of the effective fugacity at the origin for a class of diluted
ferromagnetic Ising models on the Cayley tree are presented.Comment: 22 page
Converging Perturbative Solutions of the Schroedinger Equation for a Two-Level System with a Hamiltonian Depending Periodically on Time
We study the Schroedinger equation of a class of two-level systems under the
action of a periodic time-dependent external field in the situation where the
energy difference 2epsilon between the free energy levels is sufficiently small
with respect to the strength of the external interaction. Under suitable
conditions we show that this equation has a solution in terms of converging
power series expansions in epsilon. In contrast to other expansion methods,
like in the Dyson expansion, the method we present is not plagued by the
presence of ``secular terms''. Due to this feature we were able to prove
absolute and uniform convergence of the Fourier series involved in the
computation of the wave functions and to prove absolute convergence of the
epsilon-expansions leading to the ``secular frequency'' and to the coefficients
of the Fourier expansion of the wave function
Process quality in Portuguese preschool classrooms serving children at-risk of poverty and social exclusion and children with disabilities
This study investigates process quality and structural features of classrooms serving children at-risk of poverty and social exclusion and children with disabilities in Portugal. We examine (a) whether the three-domain structure of a widely used standard observational tool, the Classroom Assessment Scoring System (CLASS; Pianta, LaParo, & Hamre, 2008) describes adequately teacher–child interactions in those classrooms and (b) associations between CLASS domains and structural features, including teacher education and group size. The study was conducted in 178 preschool classrooms. Data included classroom observations using the CLASS Pre-K and teacher reports on structural features. Confirmatory factor analysis supported the three domains of teacher–child interactions. In addition, the CLASS domains described teacher–child interactions equally well across classrooms serving children with disabilities and children at-risk of poverty and social exclusion. Finally, we found modest associations between structural features and CLASS organizational and instructional support, suggesting a complex interplay among structural features in predicting levels of teacher–child interactions.info:eu-repo/semantics/acceptedVersio
Socio-epidemiological aspects of respiratory allergic diseases in Southern Africa
The prevalence of respiratory allergic diseases has been increasing in Southern Africa both in urban and in rural environments. Various factors may contribute toward this situation, namely, exposure to aeroallergens, such as grass pollens and house dust mites. However, other irritant environmental triggers, such as exposure to tobacco smoke and certain indoor and outdoor fumes, may also play a relevant part. Furthermore, certain parasitic and mycobacterial infections may act as allergic disease risk modifiers, although such an influence should be confirmed. Finally, certain cultural and socioeconomic factors may also influence accessibility to healthcare and adherence to treatment of these diseases
Topological low-temperature limit of Z(2) spin-gauge theory in three dimensions
We study Z(2) lattice gauge theory on triangulations of a compact 3-manifold.
We reformulate the theory algebraically, describing it in terms of the
structure constants of a bidimensional vector space H equipped with algebra and
coalgebra structures, and prove that in the low-temperature limit H reduces to
a Hopf Algebra, in which case the theory becomes equivalent to a topological
field theory. The degeneracy of the ground state is shown to be a topological
invariant. This fact is used to compute the zeroth- and first-order terms in
the low-temperature expansion of Z for arbitrary triangulations. In finite
temperatures, the algebraic reformulation gives rise to new duality relations
among classical spin models, related to changes of basis of H.Comment: 10 pages, no figure
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