Perturbative quantum gravity with the Immirzi parameter

Perturbative Noncommutative Quantum Gravity

We study perturbative noncommutative quantum gravity by expanding the gravitational field about a fixed classical background. A calculation of the one loop gravitational self-energy graph reveals that only the non-planar graviton loops are damped by oscillating internal momentum dependent factors. The noncommutative quantum gravity perturbation theory is not renormalizable beyond one loop for m...

Hamiltonian dynamics and Faddeev-Jackiw quantization of 3D gravity with a Barbero-Immirzi like parameter

It is well-know that 3-dimensional gravity is an interesting toy model. In fact, it is considered as good test theory for trying to understand the difficulties that emerge in the quantization of four dimensional gravity. It is worth to mention, that since the works developed by Achucarro, Towsend, Witten and other authors [1, 2], there is a huge effort for understanding at classical and quantum...

Non-perturbative Solutions for Lattice Quantum Gravity

We propose a new, discretized model for the study of 3+1-dimensional canonical quantum gravity, based on the classical SL(2,C)-connection formulation. The discretization takes place on a topological N3-lattice with periodic boundary conditions. All operators and wave functions are constructed from one-dimensional link variables, which are regarded as the fundamental building blocks of the theor...

Non-perturbative 3d Lorentzian Quantum Gravity

We have recently introduced a discrete model of Lorentzian quantum gravity, given as a regularized non-perturbative state sum over simplicial Lorentzian spacetimes, each possessing a unique Wick rotation to Euclidean signature. We investigate here the phase structure of the Wick-rotated path integral in three dimensions with the aid of computer simulations. After fine-tuning the cosmological co...

Non-Perturbative Two-Dimensional Quantum Gravity, Again