Cosmology With Interacting Dark Energy

Abstract

The early cosmic inflation, when taken along with the recent observations that the universe is currently dominated by a low density vacuum energy, leads to at least two potential problems which modern cosmology must address. First, there is the old cosmological constant problem, with a new twist: the coincidence problem. Secondly, cosmology still lacks a model to predict the observed current cosmic acceleration and to determine whether or not there is a future exit out of this state (as previously in the inflationary case). This constitutes (what is called here) a dynamical problem. In this article a framework is proposed to address these two problems, based on treating the cosmic background vacuum (dark) energy as both dynamical and interacting. The universe behaves as a vacuum-driven cosmic engine which, in search of equilibrium, always back-reacts to vacuum-induced accelerations by increasing its inertia (internal energy) through vacuum energy dissipation. The process couples cosmic vacuum (dark) energy to matter to produce future-directed increasingly comparable amplitudes in these fields by setting up oscillations in the decaying vacuum energy density and corresponding sympathetic ones in the matter fields. By putting bounds on the relative magnitudes of these coupled oscillations the model offers a natural and conceptually simple channel to discuss the coincidence problem, while also suggesting a way to deal with the dynamical problem. A result with useful observational implications is an equation of state w(t) which specifically predicts a variable, quasi-periodic, acceleration for the current universe. This result can be directly tested by future observational techniques such as SNAP.

14 pages, latex, no figures, minor changes, version to appear in Mod. Phys. Lett. A

References in corpus (1)

• Evidence for a non-zero Lambda and a low matter density from a combined analysis of the 2dF Galaxy Redshift Survey and Cosmic Microwave Background Anisotropies

Cited by in corpus (8)

• Probing the imprint of interacting dark energy on very large scales
• Particle vs. future event horizon in interacting holographic dark energy model
• A non-singular black hole model as a possible end-product of gravitational collapse
• Dark-Energy Dynamics Required to Solve the Cosmic Coincidence
• Viscous extended holographic Ricci dark energy in the framework of standard Eckart theory
• Perturbations in the interacting vacuum
• Can gravitational collapse sustain singularity-free trapped surfaces?
• Is cosmic dynamics self-regulating?