Effective action of a five-dimensional domain wall

We calculate the four-dimensional low-energy effective action for the perturbations of a two-scalar domain wall model in five dimensions. Comparison of the effective action to the Nambu-Goto action reveals the presence of an additional coupling between the light scalar field and the massless translation mode (branon excitation), which can be written in terms of the curvature scalar of the induced metric. We comment on the impact of this interaction to branon physics.Comment: 24 page

A SUSY Inspired Simplified Model for the 750 GeV Diphoton Excess

The evidence for a new singlet scalar particle from the 750 GeV diphoton excess, and the absence of any other signal of new physics at the LHC so far, suggest the existence of new coloured scalars. To study this possibility, we propose a supersymmetry inspired simplified model, extending the Standard Model with a singlet scalar and with heavy scalar fields carrying both colour and electric charges -- the `squarks'. To allow the latter to decay, and to generate the dark matter of the Universe, we also add a neutral fermion to the particle content. We show that this model provides a two-parameter fit to the observed diphoton excess consistently with cosmology, while the allowed parameter space is bounded by the consistency of the model. In the context of our simplified model this implies the existence of other supersymmetric particles accessible at the LHC, rendering this scenario falsifiable. If this excess persists, it will imply a paradigm shift in assessing supersymmetry breaking and the role of scalars in low scale physics.Comment: 7 pages, 2 figures, SUSY incarnat

A feminist interpretation of women\u27s work with Koloa in the Tongan community

The San Francisco Bay Area is home to a Tongan community where the Tongan culture has been established. A major factor establishing Tongan culture is women’s work with koloa. Koloa are cultural materials used to fulfill customs and traditions specific to Tongan culture, which are under the control of women where they produce, possess, gift, as well as exchange koloa. Historically, women have governed the koloa tradition as guardians preserving their tradition. My thesis exploration focused on three main subjects—women, koloa, and feminism. The point of studying women from a feminist native perspective was to explore their work with koloa through shared lived experiences. Information about women’s work was developed from interviews, a survey, and observations. Methodologies such as a feminist native approach, feminist analysis, as well as autoethnography were imperative for developing an understanding of why women’s work is relevant as well as explaining that understanding by forming Tongan and Pacific Islander feminist thought. The knowledge I developed confronted aspects of previous research by moving away from producing knowledge overly focused on koloa as a form of wealth, the production of koloa, and overlooking women’s contributions through their work. Realizing women’s work is relevant because it is a resource that can be used to develop cultural knowledge as well as establish culture was a vigilant discovery defending women as respectable, key members of society. Bringing awareness to their lasting work involved changing from conventional ways of doing research to incorporating new methods to produce information

Entrepreneurial Skills Required by Mechanical Engineering Craft Practice Trade Students in Technical Colleges in Kano State, Nigeria

The study identified Entrepreneurial Skills Required by Mechanical Engineering Craft Practice Trade Students in Technical Colleges in Kano State. The study was guided by two research questions. Two null hypotheses were formulated and tested at 0.05 level of significance. A descriptive survey research design was used for the study. The population of the study comprised of 44 entrepreneurs and 24 teachers making a total of 68 respondents. The entire population was used for the study. The instrument used for data collection was a 63 items structured questionnaire. The reliability coefficient of the instrument was 0.79. Mean, Standard Deviation, and Grand Mean were used to answer research questions 1 & 2. While z-test was used to test the hypotheses at 0.05 level of significance. The findings of the study revealed among others that, technical colleges’ students of mechanical engineering craft practice trade require technical skills to operate various machines like; lathe, drilling, milling, shaping and band saw. All the hypotheses tested revealed that there is significant difference between the opinion of entrepreneurs and teachers on entrepreneurship skills required by mechanical engineering craft practice trade students in technical colleges in Kano state. Based on these findings the researchers recommend, among others, that; Entrepreneurship training should be given topmost priority. This would enable the students develop entrepreneurial technical skills and attitude necessary for gainful self or paid employment. DOI: 10.7176/JEP/10-27-08 Publication date:September 30th 201

Plasmon reflections by topological electronic boundaries in bilayer graphene

Domain walls separating regions of AB and BA interlayer stacking in bilayer graphene have attracted attention as novel examples of structural solitons, topological electronic boundaries, and nanoscale plasmonic scatterers. We show that strong coupling of domain walls to surface plasmons observed in infrared nanoimaging experiments is due to topological chiral modes confined to the walls. The optical transitions among these chiral modes and the band continua enhance the local ac conductivity, which leads to plasmon reflection by the domain walls. The imaging reveals two kinds of plasmonic standing-wave interference patterns, which we attribute to shear and tensile domain walls. We compute the electronic structure of both wall varieties and show that the tensile wall contain additional confined bands which produce a structure-specific contrast of the local conductivity. The calculated plasmonic interference profiles are in quantitative agreement with our experiments.Comment: 14 pages, 5 figure

Probing Spin-Charge Relation by Magnetoconductance in One-Dimensional Polymer Nanofibers

Polymer nanofibers are one-dimensional organic hydrocarbon systems containing conducting polymers where the non-linear local excitations such as solitons, polarons and bipolarons formed by the electron-phonon interaction were predicted. Magnetoconductance (MC) can simultaneously probe both the spin and charge of these mobile species and identify the effects of electron-electron interactions on these nonlinear excitations. Here we report our observations of a qualitatively different MC in polyacetylene (PA) and in polyaniline (PANI) and polythiophene (PT) nanofibers. In PA the MC is essentially zero, but it is present in PANI and PT. The universal scaling behavior and the zero (finite) MC in PA (PANI and PT) nanofibers provide evidence of Coulomb interactions between spinless charged solitons (interacting polarons which carry both spin and charge)

Structure and Vibrations of the Vicinal Copper (211) Surface

We report a first principles theoretical study of the surface relaxation and lattice dynamics of the Cu(211) surface using the plane wave pseudopotential method. We find large atomic relaxations for the first several atomic layers near the step edges on this surface, and a substantial step-induced renormalization of the surface harmonic force constants. We use the results to study the harmonic fluctuations around the equilibrium structure and find three new step-derived features in the zone center vibrational spectrum. Comparison of these results with previous theoretical work and weith experimental studies using inelastic He scattering are reported.Comment: 6 Pages RevTex, 7 Figures in Postscrip

Enhanced self-field critical current density of nano-composite YBa(2)Cu(3)O(7) thin films grown by pulsed-laser deposition

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ EPLA, 2008.Enhanced self-field critical current density Jc of novel, high-temperature superconducting thin films is reported. Layers are deposited on (001) MgO substrates by laser ablation of YBa2Cu3O7−δ(Y-123) ceramics containing Y2Ba4CuMOx (M-2411, M=Ag, Nb, Ru, Zr) nano-particles. The Jc of films depends on the secondary-phase content of the ceramic targets, which was varied between 0 and 15 mol%. Composite layers (2 mol% of Ag-2411 and Nb-2411) exhibit Jc values at 77 K of up to 5.1 MA/cm2, which is 3 to 4 times higher than those observed in films deposited from phase pure Y-123 ceramics. Nb-2411 grows epitaxially in the composite layers and the estimated crystallite size is ~10 nm.The Austrian Science Fund, the Austrian Federal Ministry of Economics and Labour, the European Science Foundation and the Higher Education Commission of Pakistan