4,081 research outputs found
Dimensional reduction over the quantum sphere and non-abelian q-vortices
No full textWe extend equivariant dimensional reduction techniques to the case of quantum spaces which are the product of a Kähler manifold M with the quantum two-sphere. We work out the reduction of bundles which are equivariant under the natural action of the quantum group SU q (2), and also of invariant gauge connections on these bundles. The reduction of Yang–Mills gauge theory on the product space leads to a q-deformation of the usual quiver gauge theories on M. We formulate generalized instanton equations on the quantum space and show that they correspond to q-deformations of the usual holomorphic quiver chain vortex equations on M. We study some topological stability conditions for the existence of solutions to these equations, and demonstrate that the corresponding vacuum moduli spaces are generally better behaved than their undeformed counterparts, but much more constrained by the q-deformation. We work out several explicit examples, including new examples of non-abelian vortices on Riemann surfaces, and q-deformations of instantons whose moduli spaces admit the standard hyper-Kähler quotient construction. <br/
Topological t-duality for twisted tori
No full textWe apply the C∗-algebraic formalism of topological T-duality due to Mathai and Rosenberg to a broad class of topological spaces that include the torus bundles appearing in string theory compactifications with duality twists, such as nilmanifolds, as well as many other examples. We develop a simple procedure in this setting for constructing the T-duals starting from a commutative C∗-algebra with an action of Rn. We treat the general class of almost abelian solvmanifolds in arbitrary dimension in detail, where we provide necessary and sufficient criteria for the existence of classical T-duals in terms of purely group theoretic data, and compute them explicitly as continuous-trace algebras with non-trivial Dixmier– Douady classes. We prove that any such solvmanifold has a topological T-dual given by a C∗-algebra bundle of noncommutative tori, which we also compute explicitly. The monodromy of the original torus bundle becomes a Morita equivalence among the fiber algebras, so that these C∗-algebras rigorously describe the T-folds from non-geometric string theory.</p
D-branes, KK-theory and duality on noncommutative spaces
No full textWe present a new categorical classification framework for D-brane charges on noncommutative manifolds using methods of bivariant K-theory. We describe several applications including an explicit formula for D-brane charge in cyclic homology, a refinement of open string T-duality, and a general criterion for cancellation of global worldsheet anomalies
Cheeger-Simons differential characters with compact support and Pontryagin duality
No full textBy adapting the Cheeger-Simons approach to differential cohomology, we establish a notion of differential cohomology with compact support. We show that it is functorial with respect to open embeddings and that it fits into a natural diagram of exact sequences which compare it to compactly supported singular cohomology and differential forms with compact support, in full analogy to ordinary differential cohomology. We prove an excision theorem for differential cohomology using a suitable relative version. Furthermore, we use our model to give an independent proof of Pontryagin duality for differential cohomology recovering a result of [Harvey, Lawson, Zweck -- Amer. J. Math. 125 (2003) 791]: On any oriented manifold, ordinary differential cohomology is isomorphic to the smooth Pontryagin dual of compactly supported differential cohomology. For manifolds of finite-type, a similar result is obtained interchanging ordinary with compactly supported differential cohomology
Modulation of immunity and viral-host interactions by alcohol
No full textThis manuscript represents the proceedings of a symposium at the 2001 RSA Meeting in Montreal, Canada. The organizers/chairs were Gyongyi Szabo and Geoffrey M. Thiele. The presentations were (1) Introduction, by Gyongyi Szabo; (2) Chemokine dysregulation after acute ethanol exposure, by Elizabeth J. Kovacs; (3) Chemokine production and innate immunity in the livers of simian immunodeficiency virus-infected Macaca mulatta following chronic alcohol administration, by Abraham P. Bautista; (4) Influence of ethanol consumption on the severity and progression of hepatitis associated with cytomegalovirus infection, by Laura Sosa and Thomas R. Jerrells; (5) Scavenger receptor involvement in the immune response to the metabolites of chronic ethanol ingestion, by Geoffrey M. Thiele; and (6) Mechanisms of impaired accessory cell functions due to alcohol exposure and hepatitis C infection, by Gyongyi Szabo
Matrix quantum mechanics and soliton regularization of noncommutative field theory
No full textWe construct an approximation to field theories on the noncommutative torus based on soliton projections and partial isometries which together form a matrix algebra of functions on the sum of two circles. The matrix quantum mechanics is applied to the perturbative dynamics of scalar field theory, to tachyon dynamics in string field theory, and to the Hamiltonian dynamics of noncommutative gauge theory in two dimensions. We also describe the adiabatic dynamics of solitons on the noncommutative torus and compare various classes of noncommutative solitons on the torus and the plane. © 2004 International Press.</p
Geometry of the gauge algebra in non-commutative yang-mills theory
No full textA detailed description of the infinite-dimensional Lie algebra of ⋆-gauge transformations in non-commutative Yang-Mills theory is presented. Various descriptions of this algebra are given in terms of inner automorphisms of the underlying deformed algebra of functions on spacetime, of deformed symplectic diffeomorphisms, of the infinite unitary Lie algebra u(∞), and of the C∗-algebra of compact operators on a quantum mechanical Hilbert space. The spacetime and string interpretations are also elucidated
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