21,689 research outputs found
Quantum deformation of the Dirac bracket
The quantum deformation of the Poisson bracket is the Moyal bracket. We
construct quantum deformation of the Dirac bracket for systems which admit
global symplectic basis for constraint functions. Equivalently, it can be
considered as an extension of the Moyal bracket to second-class constraints
systems and to gauge-invariant systems which become second class when
gauge-fixing conditions are imposed.Comment: 18 pages, REVTe
Crossed module actions on continuous trace -algebras
We lift an action of a torus on the spectrum of a continuous
trace algebra to an action of a certain crossed module of Lie groups that is an
extension of . We compute equivariant Brauer and Picard groups
for this crossed module and describe the obstruction to the existence of an
action of in our framework.Comment: 27 pages, added background material about T-Duality, added
references, extended section about non-associative C*-algebra
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