Inflation and Dark Energy from a Covariant Elastic Medium

Abstract

In this article, we propose a unified framework for cosmological expansion and inflation at the level of background dynamics, by modeling both the inflaton field and dark energy as a four-dimensional continuous medium, whose elastic deformation is described by a covariant vector field. Focusing on a homogeneous and isotropic background cosmology, we show that for a bulk modulus $K=1.64\times 10^{109}\text{N}\cdot {\text{m}}^{-2}$, the dark energy density decreases by a factor of $\sim 10^{122}$ while the scale factor expands $10^{28}$ times over $\sim 10^{-42}$ seconds during primordial inflation. For illustrative parameter values, our analysis suggests three potential new physical phenomena for future investigation, including longitudinal elastic modes, frequency redshifts in early-universe light, and improved fits to supernova curves. At the end of the paper, we discuss the challenges of applying the framework to inflationary perturbations, particularly the need for a consistent theory capable of producing a nearly scale-invariant power spectrum, as well as of addressing reheating, and identify these as key directions for future work.

New version, thoroughly revisited and improved. It has been published in Acta Physica Polonica B

Cited by in corpus (1)

• Analogy of space time as un elastic medium -- Can we establish a thermal expansion coefficient of space from the cosmological constant Lambda?