708 research outputs found
On the AKSZ formulation of the Rozansky-Witten theory and beyond
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
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
Supermanifolds provide a very natural ground to understand and handle
supersymmetry from a geometric point of view; supersymmetry in and
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 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
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
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
We show that stable localized topological soliton textures (skyrmions) with
topological charge 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 depending on and the effective anisotropy constant .
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 and , while the solitons with
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
nor high charges, but rather for intermediate values or
.Comment: 8 pages, 4 figure
The renormalization group and spontaneous compactification of a higher-dimensional scalar field theory in curved spacetime
The renormalization group (RG) is used to study the asymptotically free
-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 and . 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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