6533b7d3fe1ef96bd1260abf
RESEARCH PRODUCT
Running Newton Constant, Improved Gravitational Actions, and Galaxy Rotation Curves
Holger WeyerMartin Reutersubject
PhysicsHigh Energy Physics - TheoryNuclear and High Energy PhysicsAstrophysics (astro-ph)Dark matterFOS: Physical sciencesGeneral Relativity and Quantum Cosmology (gr-qc)Cosmological constantNewtonian limitAstrophysicsGeneral Relativity and Quantum CosmologyGravitationsymbols.namesakeGeneral Relativity and Quantum CosmologyClassical mechanicsHigh Energy Physics - Theory (hep-th)Einstein field equationssymbolsSchwarzschild metricWeyl transformationGalaxy rotation curveMathematical physicsdescription
A renormalization group (RG) improvement of the Einstein-Hilbert action is performed which promotes Newton's constant and the cosmological constant to scalar functions on spacetime. They arise from solutions of an exact RG equation by means of a ``cutoff identification'' which associates RG scales to the points of spacetime. The resulting modified Einstein equations for spherically symmetric, static spacetimes are derived and analyzed in detail. The modifications of the Newtonian limit due to the RG evolution are obtained for the general case. As an application, the viability of a scenario is investigated where strong quantum effects in the infrared cause Newton's constant to grow at large (astrophysical) distances. For two specific RG trajectories exact vacuum spacetimes modifying the Schwarzschild metric are obtained by means of a solution-generating Weyl transformation. Their possible relevance to the problem of the observed approximately flat galaxy rotation curves is discussed. It is found that a power law running of Newton's constant with a small exponent of the order $10^{-6}$ would account for their non-Keplerian behavior without having to postulate the presence of any dark matter in the galactic halo.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2004-10-11 |