546 research outputs found
Linear and multiplicative 2-forms
We study the relationship between multiplicative 2-forms on Lie groupoids and
linear 2-forms on Lie algebroids, which leads to a new approach to the
infinitesimal description of multiplicative 2-forms and to the integration of
twisted Dirac manifolds.Comment: to appear in Letters in Mathematical Physic
Classification of Invariant Star Products up to Equivariant Morita Equivalence on Symplectic Manifolds
In this paper we investigate equivariant Morita theory for algebras with
momentum maps and compute the equivariant Picard groupoid in terms of the
Picard groupoid explicitly. We consider three types of Morita theory:
ring-theoretic equivalence, *-equivalence and strong equivalence. Then we apply
these general considerations to star product algebras over symplectic manifolds
with a Lie algebra symmetry. We obtain the full classification up to
equivariant Morita equivalence.Comment: 28 pages. Minor update, fixed typos
Deformation Quantization of a Certain Type of Open Systems
We give an approach to open quantum systems based on formal deformation
quantization. It is shown that classical open systems of a certain type can be
systematically quantized into quantum open systems preserving the complete
positivity of the open time evolution. The usual example of linearly coupled
harmonic oscillators is discussed.Comment: Major update. Improved main statements. 21 page
Morita Equivalence, Picard Groupoids and Noncommutative Field Theories
In this article we review recent developments on Morita equivalence of star
products and their Picard groups. We point out the relations between
noncommutative field theories and deformed vector bundles which give the Morita
equivalence bimodules.Comment: Latex2e, 10 pages. Conference Proceeding for the Sendai Meeting 2002.
Some typos fixe
Integration of Dirac-Jacobi structures
We study precontact groupoids whose infinitesimal counterparts are
Dirac-Jacobi structures. These geometric objects generalize contact groupoids.
We also explain the relationship between precontact groupoids and homogeneous
presymplectic groupoids. Finally, we present some examples of precontact
groupoids.Comment: 10 pages. Brief changes in the introduction. References update
Gauged (2,2) Sigma Models and Generalized Kahler Geometry
We gauge the (2,2) supersymmetric non-linear sigma model whose target space
has bihermitian structure (g, B, J_{\pm}) with noncommuting complex structures.
The bihermitian geometry is realized by a sigma model which is written in terms
of (2,2) semi-chiral superfields. We discuss the moment map, from the
perspective of the gauged sigma model action and from the integrability
condition for a Hamiltonian vector field. We show that for a concrete example,
the SU(2) x U(1) WZNW model, as well as for the sigma models with almost
product structure, the moment map can be used together with the corresponding
Killing vector to form an element of T+T* which lies in the eigenbundle of the
generalized almost complex structure. Lastly, we discuss T-duality at the level
of a (2,2) sigma model involving semi-chiral superfields and present an
explicit example.Comment: 33 page
On Jacobi quasi-Nijenhuis algebroids and Courant-Jacobi algebroid morphisms
We propose a definition of Jacobi quasi-Nijenhuis algebroid and show that any
such Jacobi algebroid has an associated quasi-Jacobi bialgebroid. Therefore,
also an associated Courant-Jacobi algebroid is obtained. We introduce the
notions of quasi-Jacobi bialgebroid morphism and Courant-Jacobi algebroid
morphism providing also some examples of Courant-Jacobi algebroid morphisms.Comment: 14 pages, to appear in Journal of Geometry and Physic
From double Lie groupoids to local Lie 2-groupoids
We apply the bar construction to the nerve of a double Lie groupoid to obtain
a local Lie 2-groupoid. As an application, we recover Haefliger's fundamental
groupoid from the fundamental double groupoid of a Lie groupoid. In the case of
a symplectic double groupoid, we study the induced closed 2-form on the
associated local Lie 2-groupoid, which leads us to propose a definition of a
symplectic 2-groupoid.Comment: 23 pages, a few minor changes, including a correction to Lemma 6.
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