A Matter Bounce By Means of Ghost Condensation

TL;DR

This paper proposes a non-singular bouncing cosmology model using ghost condensation, allowing a stable matter bounce scenario compatible with current observations and providing an alternative to inflation for primordial fluctuation generation.

Contribution

It introduces a ghost condensate-based mechanism for a stable, non-singular matter bounce cosmology consistent with observational data.

Findings

Achieves a stable cosmological bounce with ghost condensation.

Long-wavelength fluctuations pass through the bounce unaffected.

Supports the matter bounce scenario as an alternative to inflation.

Abstract

Assuming the existence of a scalar field which undergoes "ghost condensation" and which has a suitably chosen potential, it is possible to obtain a non-singular bouncing cosmology in the presence of regular matter and radiation. The potential for the ghost condensate field can be chosen such that the cosmological bounce is stable against the presence of anisotropic stress. Cosmological fluctuations on long wavelengths relevant to current cosmological observations pass through the bounce unaffected by the new physics which yields the bounce. Thus, this model allows for the realization of the "matter bounce" scenario, an alternative to inflationary cosmology for the generation of the observed primordial fluctuations in which the inhomogeneities originate as quantum vacuum perturbations which exit the Hubble radius in the matter-dominated phase of contraction.