Cosmology in Conformal Dilatonic Gravity

by Meir Shimon

at Particles and Fields Seminar

Mon, 01 May 2017, 14:00
Physics building (#54) room 207

Abstract

Gravitation is described in the context of a dilatonic theory that is conformally related to general relativity All dimensionless ratios of fundamental dimensional quantities e g particle masses and the Planck mass as well as the relative strengths of the fundamental interactions are fixed constants An interplay between the positive energy density associated with relativistic matter and possibly with negative spatial curvature and the negative energy associated with dynamical dilaton phase results in a non singular flat cosmological model with no horizon and as a direct consequence of absence of phase transitions in the early universe with no production of topological defects The logarithmic time derivativeof the field modulus is degenerate with the Hubble function and all cosmological epochs of the standard model are unchanged except at the very early universe We demonstrate that both linear order perturbation theory and the spherical collapse model are equivalent to those in the standard model up to modifications caused by the phase of the complex scalar field and its perturbations Consequently our alternative theory automatically passes the main classical cosmological tests Quantum excitations of the phase of the scalar field generate a slightly red tilted spectrum of adiabatic and gaussian scalar perturbations on the largest scales However this framework does not provide a similar mechanism for producing primordial gravitational waves on these scales A spherically symmetric vacuum solution that approximately describes the exterior of gravitationally bound systems e g stars and galaxies by a modified Schwarzschild de Sitter metric augmented with an additional linear potential term could possibly explain galactic rotation curves and strong gravitational lensing with no recourse to dark matter

Created on 23-04-2017 by Bar Lev, Yevgeny (ybarlev)
Updaded on 23-04-2017 by Bar Lev, Yevgeny (ybarlev)