Seven-dimensional gravity with topological terms

Quantum gravity in terms of topological observables

We recast the action principle of four dimensional General Relativity so that it becomes amenable for perturbation theory which doesn’t break general covariance. The coupling constant becomes dimensionless (GNewtonΛ) and extremely small 10 . We give an expression for the generating functional of perturbation theory. We show that the partition function of quantum General Relativity can be expres...

Black holes in three-dimensional topological gravity.

Six Dimensional Topological Gravity and the Cosmological Constant Problem

We formulate a topological theory in six dimensions with gauge group SO(3, 3) which reduces to gravity on a four dimensional defect if suitable boundary conditions are chosen. In such a framework we implement the reflection automorphism of SO(3, 3) as a Z2 symmetry which forbids the appearance of a gravitational cosmological constant. Some temptative speculations are presented also for the poss...

Moduli Spaces in the Four-Dimensional Topological Half-Flat Gravity

We classify the moduli spaces of the four-dimensional topological half-flat gravity models by using the canonical bundle. For a K3-surface or T 4 , they describe an equivalent class of a trio of the Einstein-Kähler forms (the hyperkähler forms). We calculate the dimensions of these moduli spaces by using the Atiyah-Singer Index theorem. We mention the partition function and the possibility of t...

A Topological Model for Two-dimensional Gravity Coupled to Matter

Starting from a topological gauge theory in two dimensions with symmetry groups ISO(2, 1), SO(2, 1) and SO(1, 2) we construct a model for gravity with non-trivial coupling to matter. We discuss the equations of motion which are connected to those of previous related models but incorporate matter content. We also discuss the resulting quantum theory and finally present explicit formulæ for topol...