Unified Dark Energy and Dark Matter from Dynamical Spacetime Cosmology

by Mr. David Benisty

Bgu

at Astrophysics and Cosmology Seminar

Wed, 30 Oct 2019, 11:10
Sacta-Rashi Building for Physics (54), room 207

Abstract

A model of unified dark matter and dark energy based on a dynamical space time theory is studied. By introducing a dynamical space time vector field $\chi_\mu$ involves as a Lagrange multiplier, conservation of an energy momentum tensor $T^{\mu\nu}_{(\chi)}$ emerges. The action allows for two different potentials, while one represents a dynamical dark energy. For constant potentials, the cosmological solution yields a non singular bouncing solutions that rapidly approaches to the $\Lambda$CDM model. The dynamical time vector field corresponds to the cosmic time as well. The theory fits with the late time expansion data of our universe. With higher dimensions a mechanism inflation compactification appears. The early universe capable of providing exponential growth for some dimensions and exponential contraction for others, giving therefore an explanation for the big size of the observed four dimensional Universe as well as the required smallness of the extra dimensions is obtained. By demanding that the dynamical space vector field be the gradient of a scalar the dynamical space time theory becomes a theory for diffusive interacting dark energy and dark matter, which asymptotically return to $\Lambda$CDM model as an asymptotic stable point. These formulations lead to scenarios which address our understanding about the origin of the universe.

Created on 23-10-2019 by Zitrin, Adi (zitrin)
Updaded on 23-10-2019 by Zitrin, Adi (zitrin)