2008/11/30 by Ghanashyam Date, Sandipan Sengupta · 2 citations
Physics and Astronomy · #Action (physics) #Advanced Mathematical Theories and Applications #Black Holes and Theoretical Physics #Curvature #Effective action #Isotropy #Limit (mathematics) #Noncommutative and Quantum Gravity Theories #Quantum #Quantum gravity #Symmetry (geometry) #gr-qc #hep-th
paper · pdf · doi:10.1088/0264-9381/26/10/105002
published as Class.Quant.Grav.26:105002,2009 · 12 pages, revtex4. Final version. Apart from minor changes, the latter part of Section IV and section V have been revised. Conclusions unchanged. References updated
arxiv created 2009/03/30 · openalex publication_date 2009/04/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Quantum corrections of certain types and relevant in certain regimes can be summarised in terms of an effective action calculable, in principle, from the underlying theory. The demands of symmetries, local form of terms and dimensional considerations limit the form of the effective action to a great extent leaving only the numerical coefficients to distinguish different underlying theories. The effective action can be restricted to particular symmetry sectors to obtain the corresponding, \em reduced effective action. Alternatively, one can also quantize a classically (symmetry) reduced theory and obtain the corresponding effective action. These two effective actions can be compared. As an example, we compare the effective action(s) known in isotropic loop quantum cosmology with the Lovelock actions, as well as with more general actions, specialized to homogeneous isotropic space-times and find that the μ-scheme is singled out.