arXiv subjects

Simone Gutt

Publications and source records attributed to Simone Gutt.

22 records · Page 2Linked to original sources

arXiv2003

Natural star products on symplectic manifolds and quantum moment maps

We define a natural class of star products: those which are given by a series of bidifferential operators which at order $k$ in the deformation parameter have at most $k$ derivatives in each argument. We show that any such star product on a symplectic manifold defines a unique symplectic connection. We parametrise such star products, study their invariance and give necessary and sufficient conditions for them to yield a quantum moment map. We show that Kravchenko's sufficient condition for a moment map for a Fedosov star product is also necessary.

math.SG↗

arXiv2002

Traces for star products on the dual of a Lie algebra

In this paper, we describe all traces for the BCH star-product on the dual of a Lie algebra. First we show by an elementary argument that the BCH as well as the Kontsevich star-product are strongly closed if and only if the Lie algebra is unimodular. In a next step we show that the traces of the BCH star-product are given by the $\ad$-invariant functionals. Particular examples are the integration over coadjoint orbits. We show that for a compact Lie group and a regular orbit one can even achieve that this integration becomes a positive trace functional. In this case we explicitly describe the corresponding GNS representation. Finally we discuss how invariant deformations on a group can be used to induce deformations of spaces where the group acts on.

math.QA↗

arXiv2001

Traces for star products on symplectic manifolds

We give a direct elementary proof of the existence of traces for arbitrary star products on a symplectic manifold. We follow the approach we used in \cite{refs:GuttRaw}, solving first the local problem. A normalisation introduced by Karabegov \cite{refs:Karabegov} makes the local solutions unique and allows them to be pieced together to solve the global problem.

math.QA↗

arXiv2000

Variations on deformation quantization

I have chosen, in this presentation of Deformation Quantization, to focus on 3 points: the uniqueness --up to equivalence-- of a universal star product (universal in the sense of Kontsevich) on the dual of a Lie algebra, the cohomology classes introduced by Deligne for equivalence classes of differential star products on a symplectic manifold and the construction of some convergent star products on Hermitian symmetric spaces. Those subjects will appear in a promenade through the history of existence and equivalence in deformation quantization.

math.DG↗