Nikolaos Tetradis

Ansatz for the metricds 2 = a 2 (τ) [ (1 + 2Φ(τ,⃗x)) dτ 2 − (1 − 2Φ(τ,⃗x)) d⃗x d⃗x ] ,with Φ ≪ 1.Scalar fieldφ(τ,⃗x) = ¯φ(τ) + δφ(τ,⃗x),with δφ/¯φ ≪ 1. In general, ¯φ = O(1) in units of M.Density fieldρ(τ,⃗x) = ¯ρ(τ) + δρ(τ,⃗x),with δρ/¯ρ < ∼ 1.Velocity field|δ⃗v| ≪ 1.N. Tetradis University of AthensThe inhomogeneity of the Universe and the cosmological model