A new equation of state for dark energy

TL;DR

This paper proposes a novel, more complex equation of state for dark energy that relates pressure to multiple variables, leading to a linear scale factor evolution and a vacuum temperature decreasing over cosmic time.

Contribution

It introduces a new dark energy equation of state dependent on density, matter, and universe size, differing from the standard proportional model.

Findings

Cosmological scale factor is linear in time at late epochs.

Vacuum temperature is proportional to universe's acceleration and decreases over time.

The model predicts a universe expansion different from exponential growth.

Abstract

In the contemporary Cosmology, dark energy is modeled as a perfect fluid, having a very simple equation of state: pressure is proportional to dark energy density. As an alternative, I propose a more complex equation of state, with pressure being function of three variables: dark energy density, matter density and the size of the Universe. One consequence of the new equation is that, in the late-time Universe, cosmological scale factor is linear function of time; while the standard cosmology predicts an exponential function.The new equation of state allows attributing a temperature to the physical vacuum, a temperature proportional to the acceleration of the expansion of the Universe. The vacuum temperature decreases with the expansion of the Universe, approaching (but never reaching) the absolute zero.