2001/09/30 by S. A. Bludman, M. Roos · 51 citations
Physics and Astronomy · #Astrophysics #Black Holes and Theoretical Physics #Cosmological constant #Cosmology #Cosmology and Gravitation Theories #Dark energy #Equation of state #Galaxies: Formation, Evolution, Phenomena #Mathematical physics #Physics #Quantum mechanics #Quintessence #Theoretical physics #astro-ph
paper · pdf · doi:10.1103/physrevd.65.043503
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 65(4) (American Physical Society) · Typos corrected, as presented at Cosmo-01 Workshop, Rovaniemi, Finland and accepted for publication in Physical Review D. 9 pages, 4 figures
arxiv created 2001/11/15 · openalex publication_date 2002/01/11 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Within present constraints on the observed smooth energy and its equation of state parameter wQ=P/\ensuremathρQ, it is important to find out whether the smooth energy is static (cosmological constant) or dynamic (quintessence). The most dynamical quintessence fields observationally allowed are now still fast rolling and no longer satisfy the tracker approximation if the equation of state parameter varies moderately with cosmic scale a=1/1+z. We are optimistic about distinguishing between a cosmological constant and appreciably dynamic quintessence by measuring average values for the effective equation of state parameter wQ(a). However, reconstructing the quintessence potential from observations of any scale dependence wQ(a) appears problematic in the near future. For our flat universe, at present dominated by smooth energy in the form of either a cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction to be maximal at the observed smooth energy-matter ratio R0\ensuremath∼2. Identifying this collapsed fraction as a conditional probability for habitable galaxies, we infer that the prior distribution is flat in R0 or \ensuremathΩm0. Interpreting this prior as a distribution over theories, rather than as a distribution over unobservable subuniverses, leads us to heuristic predictions about the class of future quasistatic quintessence potentials.