2008/03/31 by F. R. Klinkhamer
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Noncommutative and Quantum Gravity Theories #astro-ph #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevd.78.083533
published as Phys.Rev.D78:083533,2008 · 20 pages with revtex4; v7: published version in preprint style
openalex publication_date 2008/10/23 · arxiv created 2008/10/25 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The near-zero value of the cosmological constant \ensuremathΛ in an equilibrium context may be due to the existence of a self-tuning relativistic vacuum variable q. Here, a cosmological nonequilibrium context is considered with a corresponding time-dependent cosmological parameter \ensuremathΛ(t) or vacuum energy density \ensuremathρV(t). A specific model of a closed Friedmann-Robertson-Walker universe is presented, which is determined by equilibrium boundary conditions at one instant of time (t=teq) and a particular form of vacuum-energy dynamics (d\ensuremathρV/dt\ensuremath∝\ensuremathρM). This homogeneous and isotropic model has a standard big bang phase at early times (t\ensuremath≪teq) and reproduces the main characteristics of the present universe (t=t0<teq).