2010/10/25 by Alan Lai, Lai, Alan
Mathematics · Physics and Astronomy · #FOS: Mathematics #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Mathematical Physics (math-ph) #Operator Algebras (math.OA) #gr-qc #hep-th #math-ph #math.MP #math.OA
paper · pdf · doi:10.48550/arxiv.1010.5226
27 pages, Latex2e
arxiv created 2010/10/25 · arxiv updated 2010/10/26
In attempts to combine non-commutative geometry and quantum gravity, Aastrup-Grimstrup-Nest construct a semi-finite spectral triple, modeling the space of G-connections for G=U(1) or SU(2). AGN show that the interaction between the algebra of holonomy loops and the Dirac-type operator D reproduces the Poisson structure of General Relativity in Ashtekar's loop variables. This article generalizes AGN's construction to any connected compact Lie group G. A construction of AGN's semi-finite spectral triple in terms of an inductive limit of spectral triples is formulated. The refined construction permits the semi-finite spectral triple to be even when G is even dimensional. The Dirac-type operator D in AGN's semi-finite spectral triple is a weighted sum of a basic Dirac operator on G. The weight assignment is a diverging sequence that governs the "volume" associated to each copy of G. The JLO cocycle of AGN's triple is examined in terms of the weight assignment. An explicit condition on the weight assignment perturbations is given, so that the associated JLO class remains invariant. Such a condition leads to a functoriality property of AGN's construction.