2009/05/31 by Changjun Gao · 2 citations
Physics and Astronomy · #Advanced Differential Geometry Research #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1016/j.physletb.2009.12.063
published as Phys.Lett.B684:85-91,2010 · 8 pages,8 figures. Phys.Lett.B accepted. A K-essence kind modified gravity in ADM formalism is incorporated
arxiv created 2010/01/05 · openalex publication_date 2010/01/07 · arxiv updated 2010/04/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
Motivated by Hořava–Lifshitz gravity theory, we propose and investigate two kinds of modified gravity theories, the f(R) kind and the K-essence kind, in the Arnowitt–Deser–Misner (ADM) formalism. The f(R) kind includes one ultraviolet (UV) term and one infrared (IR) term together with the Einstein–Hilbert action. We find that these two terms naturally present the ultraviolet and infrared modifications to the Friedmann equation. The UV and IR modifications can avoid the past Big-Bang singularity and the future Big–Rip singularity, respectively. Furthermore, the IR modification can naturally account for the current acceleration of the Universe. The Lagrangian of K-essence kind modified gravity is made up of the three-dimensional Ricci scalar and an arbitrary function of the extrinsic curvature term. We find the cosmic acceleration can also be naturally interpreted without invoking any kind of dark energy. The static, spherically symmetry and vacuum solutions of both theories are Schwarzschild or Schwarzschild–de Sitter solution. Thus these modified gravity theories are viable for solar system tests.