Dark energy, dissipation and the coincidence problem

Dark energy and dissipation

Most of the models leading to a current state of cosmic accelerated expansion fail to address the coincidence problem, i.e., that the dark energy density and the energy density of the matter fluid are of the same order precisely today. We show that a way to drive late acceleration and simultaneously solve the aforesaid problem is assuming the matter fluid dissipative [1]. 1 General setting The ...

Tachyon Driven Solution to Cosmic Coincidence Problem

Here, non-minimally coupled tachyon to gravity is considered as a source of dark energy. It is demonstrated that with expansion of the universe, tachyon dark energy decays to dark matter providing a solution to " cosmic coincidence problem ". Moreover, it is found that the universe undergoes accelerated expansion simultaneously. PACS nos. 98.80 Cq, 95.35.+d.

The Cosmic Coincidence Problem in the Brane World

The so called ‘cosmic coincidence’ problem seems to suggest a coupling between dark energy and dark matter. A possibility could be given by dark matter particles with masses depending exponentially on the scalar field associated to dark energy. If the latter also has an exponential potential, attractor solutions exist with constant ΩDM and ΩDE and negative effective equation of state. Due to th...

Coincidence Problem in an Oscillating Universe

We analyze an oscillating universe model in brane world scenario. The oscillating universe cycles through a series of expansions and contractions and its energy density is dominated by dust matter at early-time expansion phase and by phantom dark energy at late-time expansion phase. We find that the period of the oscillating universe is not sensitive to the tension of the brane, but sensitive t...

The effect of magnetic field on 2-D problem of generalized thermoelasticity with energy dissipation