2011/08/31 by Giovanni Marozzi, G. Marozzi, Gian Paolo Vacca +1
Economics, Econometrics and Finance · Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Stochastic processes and financial applications #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1088/0264-9381/29/11/115007
published as Class. Quantum Grav. 29, 115007 (2012) · 16 pages, latex. Comments added, errors and typos corrected, main results unchanged. Version accepted for publication in Class. Quantum Grav
arxiv created 2012/04/27 · openalex publication_date 2012/05/14 · arxiv updated 2012/05/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
In an inflationary regime driven by a free massive inflaton, we consider a class of observers which sees an inhomogeneous and isotropic Universe and derive within a genuinely gauge invariant approach the backreaction effects due to long wavelength scalar fluctuations on the associated effective Hubble factor and the equation of state. We find that, for such so-called isotropic observers, contrary to what happens for the observables defined by free-falling observers, there is an effect to leading order in the slow-roll parameter in the direction of slowing down the measured rate of expansion and of having an effective equation of state less de Sitter like. From a general point of view, the isotropic observers result has to be considered complementary to other cases (observers) in helping to characterize the physical properties of the models under investigation.