Although there is no known meaningful notion of the energy density of the gravitational field in general relativity, a few notions of quasi-local energy of gravity associated to extended but finite domains have been proposed. In this paper, the notions of quasi-local energy are studied in the framework of loop quantum gravity, in order to see whether these notions can be carried out at quantum ...

A quantum field theory formalism is reviewed that leads to a selfconsistent, finite quantum gravity, Yang-Mills and Higgs theory, which is unitary and gauge invariant to all orders of perturbation theory. The gauge hierarchy problem is solved due to the exponential damping of the Higgs self-energy loop graph for energies greater than a scale ΛH ≤ 1 TeV. The cosmological constant problem is solv...

Loop quantum gravity is a physical theory that aims at unifying general relativity and mechanics. It takes very seriously modifies it via quantisation. General describes in terms of geometry; therefore, quantising such must be equivalent to geometry what loop does. This sounds like mathematical task as well, thus, this paper we will present the mathematics gravity. We do from mathematician’s po...

We compare quantum hydrodynamics and quantum gravity. They share many common features, both have quadratic divergences, and both lead to the problem of the vacuum energy, which in the quantum gravity transforms to the cosmological constant problem. We show that in quantum liquids the vacuum energy density is not determined by the quantum zero-point energy of the phonon modes. The vacuum energy ...

In this paper we tackle the issue of causality in quantum gravity, in the context of 3d spin foam models. We identify the correct procedure for implementing the causality/orientation dependence restriction that reduces the path integral for BF theory to that of quantum gravity in first order form. We construct explicitly the resulting causal spin foam model. We then add matter degrees of freedo...

We survey indications from different branches of Physics that the fine scale structure of spacetime is not adequately described by a man-ifold. Based on the hints we accumulate, we propose a new structure, which we call a quantum topos. In the process of constructing a quantum topos for quantum gravity, we propose a new, operational approach to the problem of the obervables in quantum gravity, ...

This article gives an elementary account of the recently proposed theory spontaneous quantum gravity. It is argued that a viable gravity should be falsifiable, and hence it dynamically explain observed absence superpositions space-time geometries in its classical limit.