Publications (31)
Volume of 4-polytopes from bivectors
Benjamin Bahr
In this article we prove a formula for the volume of 4-dimensional polytopes, in terms of their face bivectors, and the crossings within their boundary graph. This proves that the…
On knottings in the physical Hilbert space of LQG as given by the EPRL model
Benjamin Bahr
We consider the EPRL spin foam amplitude for arbitrary embedded two-complexes. Choosing a definition of the face- and edge amplitudes which lead to spin foam amplitudes invariant u…
Deformation of the EPRL spin foam model by a cosmological constant
Benjamin Bahr, Giovanni Rabuffo
In this article, we consider an ad-hoc deformation of the EPRL model for quantum gravity by a cosmological constant term. This sort of deformation has been first introduced by Han…
Operator Spin Foam Models
Benjamin Bahr, Frank Hellmann, Wojciech KamiÅski +2
The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as the mai…
Regge calculus from a new angle
Benjamin Bahr, Bianca Dittrich
In Regge calculus space time is usually approximated by a triangulation with flat simplices. We present a formulation using simplices with constant sectional curvature adjusted to…
Hypercuboidal renormalization in spin foam quantum gravity
Benjamin Bahr, Sebastian Steinhaus
In this article we apply background-independent renormalization group methods to spin foam quantum gravity. It is aimed at extending and elucidating the analysis of a companion let…