708 research outputs found

    On the AKSZ formulation of the Rozansky-Witten theory and beyond

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    Using the AKSZ formalism, we construct the Batalin-Vilkovisky master action for the Rozansky-Witten model, which can be defined for any complex manifold with a closed (2,0)-form. We also construct the holomorphic version of Rozansky-Witten theory defined over Calabi-Yau 3-fold.Comment: 12 page

    Non-Commutative Batalin-Vilkovisky Algebras, Homotopy Lie Algebras and the Courant Bracket

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    We consider two different constructions of higher brackets. First, based on a Grassmann-odd, nilpotent \Delta operator, we define a non-commutative generalization of the higher Koszul brackets, which are used in a generalized Batalin-Vilkovisky algebra, and we show that they form a homotopy Lie algebra. Secondly, we investigate higher, so-called derived brackets built from symmetrized, nested Lie brackets with a fixed nilpotent Lie algebra element Q. We find the most general Jacobi-like identity that such a hierarchy satisfies. The numerical coefficients in front of each term in these generalized Jacobi identities are related to the Bernoulli numbers. We suggest that the definition of a homotopy Lie algebra should be enlarged to accommodate this important case. Finally, we consider the Courant bracket as an example of a derived bracket. We extend it to the "big bracket" of exterior forms and multi-vectors, and give closed formulas for the higher Courant brackets.Comment: 42 pages, LaTeX. v2: Added remarks in Section 5. v3: Added further explanation. v4: Minor adjustments. v5: Section 5 completely rewritten to include covariant construction. v6: Minor adjustments. v7: Added references and explanation to Section

    The symplectic origin of conformal and Minkowski superspaces

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    Supermanifolds provide a very natural ground to understand and handle supersymmetry from a geometric point of view; supersymmetry in d=3,4,6d=3,4,6 and 1010 dimensions is also deeply related to the normed division algebras. In this paper we want to show the link between the conformal group and certain types of symplectic transformations over division algebras. Inspired by this observation we then propose a new\,realization of the real form of the 4 dimensional conformal and Minkowski superspaces we obtain, respectively, as a Lagrangian supermanifold over the twistor superspace C41\mathbb{C}^{4|1} and a big cell inside it. The beauty of this approach is that it naturally generalizes to the 6 dimensional case (and possibly also to the 10 dimensional one) thus providing an elegant and uniform characterization of the conformal superspaces.Comment: 15 pages, references added, minor change

    Lattice simulations with eight flavors of domain wall fermions in SU(3) gauge theory

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    We study an SU(3) gauge theory with Nf=8 degenerate flavors of light fermions in the fundamental representation. Using the domain wall fermion formulation, we investigate the light hadron spectrum, chiral condensate and electroweak S parameter. We consider a range of light fermion masses on two lattice volumes at a single gauge coupling chosen so that IR scales approximately match those from our previous studies of the two- and six-flavor systems. Our results for the Nf=8 spectrum suggest spontaneous chiral symmetry breaking, though fits to the fermion mass dependence of spectral quantities do not strongly disfavor the hypothesis of mass-deformed infrared conformality. Compared to Nf=2 we observe a significant enhancement of the chiral condensate relative to the symmetry breaking scale F, similar to the situation for Nf=6. The reduction of the S parameter, related to parity doubling in the vector and axial-vector channels, is also comparable to our six-flavor results

    Effectiveness research of the new learning elements, initiated by the change to competency-based education model in Russia

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    Within the article the main principles for developing competency-based education, the principles for identifying competencies and the list of competencies that must be developed in a learner according to competency-based model, are analyzed. The new learning elements, initiated by the change to the competency-based education model in Russian Federation and by the new demands of Ministry of Education and Science of Russian Federation, have been included. The new learning elements have been analyzed for the compliance with the considered principles of developing competencies. The competencies, which are developed by each particular learning element, have been identified. The results of an experiment on developing competencies in two groups of students - taught with the use of new learning elements, and taught by traditional means, have been considered. (C) 2015 The Authors. Published by Elsevier Ltd

    Stable topological textures in a classical 2D Heisenberg model

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    We show that stable localized topological soliton textures (skyrmions) with π2\pi_2 topological charge ν1\nu \geq 1 exist in a classical 2D Heisenberg model of a ferromagnet with uniaxial anisotropy. For this model the soliton exist only if the number of bound magnons exceeds some threshold value NcrN_{\rm cr} depending on ν\nu and the effective anisotropy constant KeffK_{\rm eff}. We define soliton phase diagram as the dependence of threshold energies and bound magnons number on anisotropy constant. The phase boundary lines are monotonous for both ν=1\nu=1 and ν>2\nu >2, while the solitons with ν=2\nu=2 reveal peculiar nonmonotonous behavior, determining the transition regime from low to high topological charges. In particular, the soliton energy per topological charge (topological energy density) achieves a minimum neither for ν=1\nu=1 nor high charges, but rather for intermediate values ν=2\nu=2 or ν=3\nu=3.Comment: 8 pages, 4 figure

    The renormalization group and spontaneous compactification of a higher-dimensional scalar field theory in curved spacetime

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    The renormalization group (RG) is used to study the asymptotically free ϕ63\phi_6^3-theory in curved spacetime. Several forms of the RG equations for the effective potential are formulated. By solving these equations we obtain the one-loop effective potential as well as its explicit forms in the case of strong gravitational fields and strong scalar fields. Using zeta function techniques, the one-loop and corresponding RG improved vacuum energies are found for the Kaluza-Klein backgrounds R4×S1×S1R^4\times S^1\times S^1 and R4×S2R^4\times S^2. They are given in terms of exponentially convergent series, appropriate for numerical calculations. A study of these vacuum energies as a function of compactification lengths and other couplings shows that spontaneous compactification can be qualitatively different when the RG improved energy is used.Comment: LaTeX, 15 pages, 4 figure
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