13,091 research outputs found

    Coherent state triplets and their inner products

    Full text link
    It is shown that if H is a Hilbert space for a representation of a group G, then there are triplets of spaces F_H, H, F^H, in which F^H is a space of coherent state or vector coherent state wave functions and F_H is its dual relative to a conveniently defined measure. It is shown also that there is a sequence of maps F_H -> H -> F^H which facilitates the construction of the corresponding inner products. After completion if necessary, the F_H, H, and F^H, become isomorphic Hilbert spaces. It is shown that the inner product for H is often easier to evaluate in F_H than F^H. Thus, we obtain integral expressions for the inner products of coherent state and vector coherent state representations. These expressions are equivalent to the algebraic expressions of K-matrix theory, but they are frequently more efficient to apply. The construction is illustrated by many examples.Comment: 33 pages, RevTex (Latex2.09) This paper is withdrawn because it contained errors that are being correcte

    An exactly solvable model of a superconducting to rotational phase transition

    Full text link
    We consider a many-fermion model which exhibits a transition from a superconducting to a rotational phase with variation of a parameter in its Hamiltonian. The model has analytical solutions in its two limits due to the presence of dynamical symmetries. However, the symmetries are basically incompatible with one another; no simple solution exists in intermediate situations. Exact (numerical) solutions are possible and enable one to study the behavior of competing but incompatible symmetries and the phase transitions that result in a semirealistic situation. The results are remarkably simple and shed light on the nature of phase transitions.Comment: 11 pages including 1 figur

    Evaluation of an On-Campus Program Bridging the Theory-Practice Gap in Occupational Therapy Education: Student Perspective

    Get PDF
    The transfer of learning from an academic setting to fieldwork and vice versa is not straightforward and occupational therapy students often report this as challenging. In acknowledgement of this, the fieldwork placement learning structure within the Bachelor and Master occupational therapy entry-level programs at a higher education institute was redesigned to enhance links between taught content at university and fieldwork placement. The aim of this study was to explore occupational therapy students’ perspectives of this new educational initiative. The students attended university for a set number of days over the course of their first and second fieldwork placements. The sessions were focused on assisting students to make connections between theory taught at university to the practice setting and allow time for reflection and consolidation of learning. One hundred and fifteen occupational therapy students completed an anonymized online questionnaire to evaluate their experiences consisting of open and closed questions. Qualitative data was analyzed using thematic analysis and Likert Scale data was analyzed descriptively. Three key themes were identified from the qualitative information: reflection, support, and understanding and knowledge. The students reported the sessions provided time for reflection, which enabled them to link theory to practice more clearly and peer support was highly regarded. The introduction of university days during fieldwork education was overall positively received by students. This educational approach helped students to better understand theory and promoted reflection on practice experiences. This may be a useful approach to bridge the gap between theory and practice

    Investigation of nonlinear interaction phenomena in the ionosphere

    Get PDF
    Ionospheric phenomena as thermal radiation noise, propagation of naturally occurring radio noise through ionosphere, and generation of very low frequency emission

    History And Development Of The Jasper Negro High School 1975 to 1935 at Jasper, Texas

    Get PDF
    Since we began our work here In 1924, we have been asked many times by persons In various parts of the state end out of the state Just how we have done what we have in a community lite this, which is almost wholly rural, where the colored people own such little and apparently are illiterate and so indifferent to educational progress. Supervisors from the Department of Education in Texas and from Prairie View State College have visited us from time to time and have inquired How did you do it? Field agents from the General Education Board and the Plater Board have come to us several times and they always expressed themselves as agreeably surprised at our accomplishments and asked us to explain how we did it* Even our lovable local people who have been in the thickest of the fight, so to speak, and members of too teaching staff and members of the local Board of Education have asked how we did it. It Is the purpose of this study to make an effort, though a feeble one, to explain briefly how we did it The method used in this study has been to Interview old residents, both white and colored, and to make personal observations

    Control of macrophytes by grass carp (ctenopharyngodon idella) in a Waikato drain, New Zealand

    Get PDF
    Hornwort (Ceratophyllum demersum L.) and other aquatic macrophytes have historically been mechanically removed from the Rangiriri drain and Churchill East drain to maintain drain efficiency. As an alternative control method for the high plant biomass that accumulates at the end of summer, the effect of stocking diploid grass carp (Ctenopharyngodon idella L.) on the aquatic vegetation was evaluated in these Waikato drainage systems. At the start of the trial, both drains had a low diversity of aquatic macrophytes, and of the nine species (including the emergents), seven were exotic. Two months after grass carp were released to Churchill East drain (the treated drain) the four submerged and floating macrophyte species became scarce in the main drain. Over the same period, these species increased in biomass in Rangiriri drain (the untreated drain), where hornwort became dense and surface-reaching and remained so for the duration of the trial. However, grass carp did not control submerged vegetation in smaller side drains or the shallow, upper parts of the main drain, or the marginal sprawling species and emergent species. The cost of leasing the grass carp was similar to the cost of clearing the drains mechanically, but grass carp provided continuous weed control. However, subsequent to this trial, 62 dead grass carp were found in Churchill East drain in February 2001, and weed cover subsequently increased. This illustrates that grass carp management in New Zealand agricultural drains can be problematic due to periodic fish kills

    On giant piezoresistance effects in silicon nanowires and microwires

    Full text link
    The giant piezoresistance (PZR) previously reported in silicon nanowires is experimentally investigated in a large number of surface depleted silicon nano- and micro-structures. The resistance is shown to vary strongly with time due to electron and hole trapping at the sample surfaces. Importantly, this time varying resistance manifests itself as an apparent giant PZR identical to that reported elsewhere. By modulating the applied stress in time, the true PZR of the structures is found to be comparable with that of bulk silicon

    Representations of the Weyl group and Wigner functions for SU(3)

    Full text link
    Bases for SU(3) irreps are constructed on a space of three-particle tensor products of two-dimensional harmonic oscillator wave functions. The Weyl group is represented as the symmetric group of permutations of the particle coordinates of these space. Wigner functions for SU(3) are expressed as products of SU(2) Wigner functions and matrix elements of Weyl transformations. The constructions make explicit use of dual reductive pairs which are shown to be particularly relevant to problems in optics and quantum interferometry.Comment: : RevTex file, 11 pages with 2 figure

    Vector coherent state representations, induced representations, and geometric quantization: II. Vector coherent state representations

    Get PDF
    It is shown here and in the preceeding paper (quant-ph/0201129) that vector coherent state theory, the theory of induced representations, and geometric quantization provide alternative but equivalent quantizations of an algebraic model. The relationships are useful because some constructions are simpler and more natural from one perspective than another. More importantly, each approach suggests ways of generalizing its counterparts. In this paper, we focus on the construction of quantum models for algebraic systems with intrinsic degrees of freedom. Semi-classical partial quantizations, for which only the intrinsic degrees of freedom are quantized, arise naturally out of this construction. The quantization of the SU(3) and rigid rotor models are considered as examples.Comment: 31 pages, part 2 of two papers, published versio

    Collective states of the odd-mass nuclei within the framework of the Interacting Vector Boson Model

    Full text link
    A supersymmetric extension of the dynamical symmetry group SpB(12,R)Sp^{B}(12,R) of the Interacting Vector Boson Model (IVBM), to the orthosymplectic group OSp(2Ω/12,R)OSp(2\Omega/12,R) is developed in order to incorporate fermion degrees of freedom into the nuclear dynamics and to encompass the treatment of odd mass nuclei. The bosonic sector of the supergroup is used to describe the complex collective spectra of the neighboring even-even nuclei and is considered as a core structure of the odd nucleus. The fermionic sector is represented by the fermion spin group SOF(2Ω)SUF(2)SO^{F}(2\Omega)\supset SU^{F}(2). The so obtained, new exactly solvable limiting case is applied for the description of the nuclear collective spectra of odd mass nuclei. The theoretical predictions for different collective bands in three odd mass nuclei, namely 157Gd^{157}Gd, 173Yb^{173}Yb and 163Dy^{163}Dy from rare earth region are compared with the experiment. The B(E2)B(E2) transition probabilities for the 157Gd^{157}Gd and 163Dy^{163}Dy between the states of the ground band are also studied. The important role of the symplectic structure of the model for the proper reproduction of the B(E2)B(E2) behavior is revealed. The obtained results reveal the applicability of the models extension.Comment: 18 pages, 8 figure
    corecore