Action Of Quantum Gravity Research Articles

Does the Vilkovisky-De Witt effective action in quantum gravity depend on the configuration space metric?

The dependence on the configuration space metric of the Vilkovisky-De Witt effective action in quantum gravity is discussed. As an example d-dimensional Einstein gravity on the flat background R d or R k× T d−k is considered, where the one-loop Vilkovisky-De Witt effective action with the one-parameter dependent configuration space metric is calculated. The dependence on the configuration space metric of the Vilkovisky-De Witt EA in gravity on the space R 4× S 1 has been investigated for the first time by Huggins, Kunstatter, Leivo and Toms.

From coadjoint orbits to scale invariant WZNW type actions and 2D quantum gravity action

By using a geometrical procedure outlined by Balachandran we are able to show that the Wess-Zumino-Novikov-Witten action arises naturally from the coadjoint orbit of a purely central extended coadjoint vector of the Kac-Moody group. Consideration of other orbits leads to an action thhat motivates us to write a possibly new class of scale invariant models which are “interacting” WZNW models. We are able to construct several scale invariant theories that appear to be interacting WZNW models. We then apply these techniques to the Virasoro group and show explicitly that the coadjoint orbit corresponding to Diff S 1/S 1 leads precisely to Polyakov's 2D quantum gravity which uses the light-cone gauge. From here it is possible to consider any arbitrary coadjoint orbit and construct an action. In particular, we are able to write actions for the orbits Diff S 1/SL(2, R ) n invariant under L n , L 0, L − n of the Viraso algebra. We make several comments with regard to extending these models.

Two-loop effective action in quantum gravity

The two-loop effective action in Einstein quantum gravity on the background M N × T k (where M N is Minkowski space, T k is a k-dimensional torus) is calculated. The spontaneous compactification with account of quantum-gravitational corrections is discussed.

Vilkovisky effective action in quantum gravity with matter

Vilkovisky effective action in quantum gravity with matter

The generalized Schwinger-DeWitt technique and the unique effective action in quantum gravity

We consider the one-loop approximation to the recently proposed unique effective action in gauge theory. The Schwinger-DeWitt technique is generalized and applied to the computation of the unique gravitational counterterms. The issue of asymptotic freedom is reexamined.

Approximate Effective Action for Quantum Gravity

A new gauge-invariant effective action is proposed for quantum gravity, based on older results that go beyond finite-order perturbation theory. Expressed in coordinate space rather than momentum space it should find important applications in the theory of the early universe.