4,659 research outputs found
Evolution of magnetic Dirac bosons in a honeycomb lattice
We examine the presence and evolution of magnetic Dirac nodes in the
Heisenberg honeycomb lattice. Using linear spin theory, we evaluate the
collinear phase diagram as well as the change in the spin dynamics with various
exchange interactions. We show that the ferromagnetic structure produces
bosonic Dirac and Weyl points due to the competition between superexchange
interactions. Furthermore, it is shown that the criteria for magnetic Dirac
nodes are coupled to the magnetic structure and not the overall crystal
symmetry, where the breaking of inversion symmetry greatly affects the
antiferromagnetic configurations. The tunability of the nodal points through
variation of the exchange parameters leads to the possibility of controlling
Dirac symmetries through an external manipulation of the orbital interactions.Comment: 9 pages, 7 figures, Submitted for publicatio
Is the ground state of Yang-Mills theory Coulombic?
We study trial states modelling the heavy quark-antiquark ground state in
SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a
thin string of glue is found to be a poor description of the continuum ground
state; the infinitesimal thickness of the string leads to UV artifacts which
suppress the overlap with the ground state. Contrastingly, a state which
surrounds the quarks with non-abelian Coulomb fields is found to have a good
overlap with the ground state for all charge separations. In fact, the overlap
increases as the lattice regulator is removed. This opens up the possibility
that the Coulomb state is the true ground state in the continuum limit.Comment: 10 pages, 9 .eps figure
The -Daugavet property for function spaces
A natural extension of the Daugavet property for -convex Banach function
spaces and related classes is analysed. As an application, we extend the
arguments given in the setting of the Daugavet property to show that no
reflexive space falls into this class
A Socio-Spatial Approach to Enable Inclusive Well-Being in Cities: A Case Study of Birmingham, UK
This article examines density and deprivation, the two important parameters that define health and well-being in cities. Discussions are drawn from a case study conducted in Birmingham in four neighborhoods characterized by their different population density and deprivation levels. Data were collected through questionnaires developed from a set of subjective well-being measures and built environment audits, based on the Irvine Minnesota Inventory that evaluates the quality of streets and walkability in neighborhoods. The inferences from the study support the need for linking health, planning, policy and design research and decision-making to the socio-spatial practices of people, impacting well-being at the everyday level. The findings provide a holistic approach health and well-being research and suggests a conceptual framework for inclusive well-being in cities, which signifies the role of social and spatial parameters in determining peoples’ health and well-being. The study also highlights the lack of interdisciplinary research in understanding the association between well-being and social and behavioral practices in diverse communities
Development of the technology for obtaining a thick extract from fruits of milk thistle with the stage of ultrasonic influence
This article presents the results of the development of technology for obtaining a thick extract of milk thistle fruits using ultrasonic treatment of plant material and extractant in the soaking stage. Materials and Methods: For the research, crushed fruits of milk thistle from “Biokor” Ltd, Penza, Russia, series 011216 were used, and the shelf life is 2 year
Higher-order Abel equations: Lagrangian formalism, first integrals and Darboux polynomials
A geometric approach is used to study a family of higher-order nonlinear Abel
equations. The inverse problem of the Lagrangian dynamics is studied in the
particular case of the second-order Abel equation and the existence of two
alternative Lagrangian formulations is proved, both Lagrangians being of a
non-natural class (neither potential nor kinetic term). These higher-order Abel
equations are studied by means of their Darboux polynomials and Jacobi
multipliers. In all the cases a family of constants of the motion is explicitly
obtained. The general n-dimensional case is also studied
Two-Fermion Production in Electron-Positron Collisions
This report summarizes the results of the two-fermion working group of the
LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the
theoretical calculations of the two fermion production process in the
electron-positron collision at LEP2 center of the mass energies are reported.
The Bhabha process and the production of muon, tau, neutrino and quark pairs is
covered. On the basis of comparison of various calculations, theoretical
uncertainties are estimated and compared with those needed for the final LEP2
data analysis. The subjects for the further studies are identified.Comment: 2-fermion working group report of the LEP2 Monte Carlo Workshop
1999/2000, 113 pages, 24 figures, 35 table
Effect of 3d-doping on the electronic structure of BaFe2As2
The electronic structure of BaFe2As2 doped with Co, Ni, and Cu has been
studied by a variety of experimental and theoretical methods, but a clear
picture of the dopant 3d states has not yet emerged. Herein we provide
experimental evidence of the distribution of Co, Ni, and Cu 3d states in the
valence band. We conclude that the Co and Ni 3d states provide additional free
carriers to the Fermi level, while the Cu 3d states are found at the bottom of
the valence band in a localized 3d10 shell. These findings help shed light on
why superconductivity can occur in BaFe2As2 doped with Co and Ni but not Cu.Comment: 18 pages, 8 figure
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