Tsuguhiko Asakawa

Noncommutative gauge theories from deformation quantization

Abstract We construct noncommutative gauge theories based on the notion of the Weyl bundle, which appears in Fedosovs construction of deformation quantization on an arbitrary symplectic manifold. These correspond to D-brane worldvolume theories in non-constant B-field and curved backgrounds in string theory. All such theories are embedded into a “universal” gauge theory of the Weyl bundle. This shows that the combination of a background field and a noncommutative field strength has universal meaning as a field strength of the Weyl bundle. We also show that the gauge equivalence relation is a part of such a “universal” gauge symmetry.

D-branes in generalized geometry and Dirac-Born-Infeld action

A bstractThe purpose of this paper is to formulate the Dirac-Born-Infeld (DBI) action in a framework of generalized geometry and clarify its symmetry. A D-brane is defined as a Dirac structure where scalar fields and gauge field are treated on an equal footing in a static gauge. We derive generalized Lie derivatives corresponding to the diffeomorphism and B- field gauge transformations and show that the DBI action is invariant under non-linearly realized symmetries for all types of diffeomorphisms and B-field gauge transformations. Consequently, we can interpret not only the scalar field but also the gauge field on the D-brane as the generalized Nambu-Goldstone boson.

Poisson-generalized geometry and

We study a new kind of Courant algebroid on Poisson manifolds, which is a variant of the generalized tangent bundle in the sense that the roles of tangent and the cotangent bundle are exchanged. Its symmetry is a semidirect product of

R

\beta

-flux

-diffeomorphisms and

D-brane on Poisson manifold and generalized geometry

\beta

ONE-LOOP TACHYON AMPLITUDE IN UNORIENTED OPEN-CLOSED STRING FIELD THEORY

-transformations. It is a starting point of an alternative version of the generalized geometry based on the cotangent bundle, such as Dirac structures and generalized Riemannian structures. In particular,

Gravity theory on Poisson manifold with R-flux

R

Noncommutative solitons of gravity

-fluxes are formulated as a twisting of this Courant algebroid by a local

Topological T-duality via Lie algebroids and

\beta