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marcus

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## Main Question or Discussion Point

This thread is in case discussion of the following paper is wished.

http://arxiv.org/abs/1102.0954

Frank Pfaeffle, Christoph A. Stephan

11 pages

(Submitted on 4 Feb 2011)

"We investigate the Holst action for closed Riemannian 4-manifolds with orthogonal connections. For connections whose torsion has zero Cartan type component we show that the Holst action can be recovered from the heat asymptotics for the natural Dirac operator acting on left-handed spinor fields."

(If anyone is coming in new to this, Holst action is the action used in Spinfoam LQG and Spectral Action Principle means they are talking Connes NC geometry realization of standard model matter. The title indicates they want to put Connes-style standard model matter together with LQG, which in fact is where they are going in the paper. They reference the standard LQG books Rovelli and Thiemann, and basic Connes and Chamseddine NCG papers about standard model matter. It seems to me that Pfaeffle and Stephan are trying to do something like what John Barrett was saying should be done in his January 2011 paper.)

In post #1410 of the QG bibliography I logged a paper by John Barrett, "Induced standard model and unification" which has now been given a new title:

http://arxiv.org/abs/1101.6078

John W. Barrett

13 pages

(Submitted on 31 Jan 2011)

"A proposal that the bosonic action of the standard model is induced from the fermionic action is investigated. It is suggested that this might occur naturally in state sum models."

http://arxiv.org/abs/1102.0954

**The Holst Action by the Spectral Action Principle**Frank Pfaeffle, Christoph A. Stephan

11 pages

(Submitted on 4 Feb 2011)

"We investigate the Holst action for closed Riemannian 4-manifolds with orthogonal connections. For connections whose torsion has zero Cartan type component we show that the Holst action can be recovered from the heat asymptotics for the natural Dirac operator acting on left-handed spinor fields."

(If anyone is coming in new to this, Holst action is the action used in Spinfoam LQG and Spectral Action Principle means they are talking Connes NC geometry realization of standard model matter. The title indicates they want to put Connes-style standard model matter together with LQG, which in fact is where they are going in the paper. They reference the standard LQG books Rovelli and Thiemann, and basic Connes and Chamseddine NCG papers about standard model matter. It seems to me that Pfaeffle and Stephan are trying to do something like what John Barrett was saying should be done in his January 2011 paper.)

In post #1410 of the QG bibliography I logged a paper by John Barrett, "Induced standard model and unification" which has now been given a new title:

http://arxiv.org/abs/1101.6078

**State sum models, induced gravity and the spectral action**John W. Barrett

13 pages

(Submitted on 31 Jan 2011)

"A proposal that the bosonic action of the standard model is induced from the fermionic action is investigated. It is suggested that this might occur naturally in state sum models."

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