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RESEARCH PRODUCT
Renormalization group improved gravitational actions: A Brans-Dicke approach
Holger WeyerMartin Reutersubject
High Energy Physics - TheoryPhysicsNuclear and High Energy PhysicsSpacetimeScalar (mathematics)FOS: Physical sciencesEnergy–momentum relationGeneral Relativity and Quantum Cosmology (gr-qc)Cosmological constantRenormalization groupGeneral Relativity and Quantum CosmologyGravitationGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theory (hep-th)Gravitational fieldQuantum mechanicsQuantum gravityMathematical physicsdescription
A new framework for exploiting information about the renormalization group (RG) behavior of gravity in a dynamical context is discussed. The Einstein-Hilbert action is RG-improved by replacing Newton's constant and the cosmological constant by scalar functions in the corresponding Lagrangian density. The position dependence of $G$ and $\Lambda$ is governed by a RG equation together with an appropriate identification of RG scales with points in spacetime. The dynamics of the fields $G$ and $\Lambda$ does not admit a Lagrangian description in general. Within the Lagrangian formalism for the gravitational field they have the status of externally prescribed ``background'' fields. The metric satisfies an effective Einstein equation similar to that of Brans-Dicke theory. Its consistency imposes severe constraints on allowed backgrounds. In the new RG-framework, $G$ and $\Lambda$ carry energy and momentum. It is tested in the setting of homogeneous-isotropic cosmology and is compared to alternative approaches where the fields $G$ and $\Lambda$ do not carry gravitating 4-momentum. The fixed point regime of the underlying RG flow is studied in detail.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2003-11-21 | Physical Review D |