Isogrowth Cosmology (and How to Map the Universe)

TL;DR

This paper introduces the concept of isogrowth cosmologies, deriving relations that allow different expansion histories to share the same growth history, emphasizing the importance of diverse observations for understanding the universe.

Contribution

It provides a theoretical framework for mapping cosmologies with identical growth but different expansion histories, extending beyond standard models.

Findings

Derived expressions for isogrowth cosmologies.

Highlighted the need for multiple observational probes.

Showed how different expansion histories can produce similar growth patterns.

Abstract

While general relativity ties together the cosmic expansion history and growth history of large scale structure, beyond the standard model these can have independent behaviors. We derive expressions for cosmologies with identical growth histories but different expansion histories, or other deviations. This provides a relation for isogrowth cosmologies, but also highlights in general the need for observations to measure each of the growth, expansion, gravity, and dark matter property histories.