Author pages are created from data sourced from our academic publisher partnerships and public sources.
Share This Author
Broken) Gauge symmetries and constraints in Regge calculus
We will examine the issue of diffeomorphism symmetry in simplicial models of (quantum) gravity, in particular for Regge calculus. We find that for a solution with curvature there do not exist exact…
A new realization of quantum geometry
We construct in this article a new realization of quantum geometry, which is obtained by quantizing the recently-introduced flux formulation of loop quantum gravity. In this framework, the vacuum is…
Towards a cosmological subsector of spin foam quantum gravity
We examine the four dimensional path integral for Euclidean quantum gravity in the context of the EPRL-FK spin foam model. The state sum is restricted to certain symmetric configurations which…
Improved and Perfect Actions in Discrete Gravity
We consider the notion of improved and perfect actions within Regge calculus. These actions are constructed in such a way that they - although being defined on a triangulation - reproduce the…
On background-independent renormalization of spin foam models
- B. Bahr
- 7 March 2017
Investigation of the spinfoam path integral with quantum cuboid intertwiners
In this work, we investigate the 4d path integral for Euclidean quantum gravity on a hypercubic lattice, as given by the Spin Foam model by Engle, Pereira, Rovelli, Livine, Freidel and Krasnov…
Coarse-graining free theories with gauge symmetries: the linearized case
The method of perfect actions is discussed, which attempts to restore gauge symmetries by mirroring exactly continuum physics on a lattice via a coarse graining process through the discretization of linearized gravity.
Discretisations, Constraints and Diffeomorphisms in Quantum Gravity
The Consistent Discretizations approach is reviewed, which is an ap- plication of the master constraint program to construct the physical Hilbert space of the canonical theory, as well as the Perfect Actions approach, which aims at finding a path integral measure with the correct symmetry behavior under diffeomorphisms.
Numerical Evidence for a Phase Transition in 4D Spin-Foam Quantum Gravity.
It appears that the critical point between the phases is precisely where broken diffeomorphism symmetry is restored, which suggests that it might allow us to define a continuum limit of the quantum gravity theory.
Perfect discretization of reparametrization invariant path integrals
It is shown that a discretized path integral with reparametrization-invariance is necessarily also discretization independent and therefore uniquely determined by the corresponding continuum quantum mechanical propagator, akin to a Wilsonian RG flow.