1,294 research outputs found
Evolution of transport properties of BaFe2-xRuxAs2 in a wide range of isovalent Ru substitution
The effects of isovalent Ru substitution at the Fe sites of BaFe2-xRuxAs2 are
investigated by measuring resistivity and Hall coefficient on high-quality
single crystals in a wide range of doping (0 < x < 1.4). Ru substitution
weakens the antiferromagnetic (AFM) order, inducing superconductivity for
relatively high doping level of 0.4 < x < 0.9. Near the AFM phase boundary, the
transport properties show non-Fermi-liquid-like behaviors with a
linear-temperature dependence of resistivity and a strong temperature
dependence of Hall coefficient with a sign change. Upon higher doping, however,
both of them recover conventional Fermi-liquid behaviors. Strong doping
dependence of Hall coefficient together with a small magnetoresistance suggest
that the anomalous transport properties can be explained in terms of
anisotropic charge carrier scattering due to interband AFM fluctuations rather
than a conventional multi-band scenario.Comment: 7 pages, 6 figures, submitted to Phys. Rev.
Hochschild (co)homology of the second kind I
We define and study the Hochschild (co)homology of the second kind (known
also as the Borel-Moore Hochschild homology and the compactly supported
Hochschild cohomology) for curved DG-categories. An isomorphism between the
Hochschild (co)homology of the second kind of a CDG-category B and the same of
the DG-category C of right CDG-modules over B, projective and finitely
generated as graded B-modules, is constructed. Sufficient conditions for an
isomorphism of the two kinds of Hochschild (co)homology of a DG-category are
formulated in terms of the two kinds of derived categories of DG-modules over
it. In particular, a kind of "resolution of the diagonal" condition for the
diagonal CDG-bimodule B over a CDG-category B guarantees an isomorphism of the
two kinds of Hochschild (co)homology of the corresponding DG-category C.
Several classes of examples are discussed.Comment: LaTeX 2e, 67 pages. v.2: The case of matrix factorizations discussed
in detail in the new subsections 4.8 and 4.1
On the Hochschild-Kostant-Rosenberg map for graded manifolds
We show that the Hochschild-Kostant-Rosenberg map from the space of
multivector fields on a graded manifold N (endowed with a Berezinian volume) to
the cohomology of the algebra of multidifferential operators on N (as a
subalgebra of the Hochschild complex of the algebra of smooth functions on N)
is an isomorphism of Batalin-Vilkovisky algebras. These results generalize to
differential graded manifolds.Comment: 15 pages. Problematic Lemma 5.5 of v1 removed and Theorem 5.3b
corrected accordingly. Exposition reorganized. To appear in IMR
The blob complex
Given an n-manifold M and an n-category C, we define a chain complex (the
"blob complex") B_*(M;C). The blob complex can be thought of as a derived
category analogue of the Hilbert space of a TQFT, and as a generalization of
Hochschild homology to n-categories and n-manifolds. It enjoys a number of nice
formal properties, including a higher dimensional generalization of Deligne's
conjecture about the action of the little disks operad on Hochschild cochains.
Along the way, we give a definition of a weak n-category with strong duality
which is particularly well suited for work with TQFTs.Comment: 106 pages. Version 3 contains many improvements following suggestions
from the referee and others, and some additional materia
Graph complexes in deformation quantization
Kontsevich's formality theorem and the consequent star-product formula rely
on the construction of an -morphism between the DGLA of polyvector
fields and the DGLA of polydifferential operators. This construction uses a
version of graphical calculus. In this article we present the details of this
graphical calculus with emphasis on its algebraic features. It is a morphism of
differential graded Lie algebras between the Kontsevich DGLA of admissible
graphs and the Chevalley-Eilenberg DGLA of linear homomorphisms between
polyvector fields and polydifferential operators. Kontsevich's proof of the
formality morphism is reexamined in this light and an algebraic framework for
discussing the tree-level reduction of Kontsevich's star-product is described.Comment: 39 pages; 3 eps figures; uses Xy-pic. Final version. Details added,
mainly concerning the tree-level approximation. Typos corrected. An abridged
version will appear in Lett. Math. Phy
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