2002/02/21 by Plamen P. Fiziev, Fiziev, Plamen P.
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.48550/arxiv.gr-qc/0202074
34 pages, 5 figures, LaTeX file, added references, corrected typos
arxiv created 2002/07/02 · arxiv updated 2009/11/30
We present a class of simple scalar-tensor models of gravity with one scalar field (dilaton Φ) and only one unknown function (cosmological potential U(Φ)). These models might be considered as a stringy inspired ones with broken SUSY. They have the following basic properties: 1) Positive dilaton mass, mΦ, and positive cosmological constant Λ, define two extremely different scales. The models under consideration are consistent with the known experimental facts if mΦ> 10-3 eV and Λ=Λobs∼ 10-56 cm-2. 2) Einstein week equivalence principle is strictly satisfied and extended to scalar-tensor theories of gravity using a novel form of principle of "constancy of fundamental constants". 3) The dilaton plays simultaneously role of inflation field and quintessence field and yields a sequential hyper-inflation with graceful exit to asymptotic de Sitter space-time which is an attractor, and is approached as exp(-√3Λobs ct/2). The time duration of inflation is Δtinfl ∼ mΦ-1. 4) Ultra-high frequency (ωΦ∼ mΦ) dilatonic oscillations take place in asymptotic regime. 5) No fine tuning. (The Robertson-Walker solutions of general type have the above properties.) 6) A novel adjustment mechanism for cosmological constant problem seems to be possible: the huge value of cosmological constant in the stringy frame is re-scaled to its observed value by dilaton after transition to phenomenological frame.